Skip to navigation – Site map

HomeNuméros18Section 2. Science in Progress. N...Delusion, reality and intersubjec...

Section 2. Science in Progress. New Conceptual Frames for Empirical Psychopathology and for Psychiatry

Delusion, reality and intersubjectivity: A phenomenological and enactive analysis

Thomas Fuchs
p. 120-143


According to current representationalist concepts, delusion is considered the result of faulty information processing or incorrect inference about external reality. In contrast, the paper develops a concept of delusion as a disturbance of the enactive and intersubjective constitution of a shared reality. A foundation of this concept is provided by a theory of the objectivity of perception which is achieved on two levels: (1) On the first level, the sensorimotor interaction with the environment implies a mobility and multiplicity of perspectives that relativizes the momentary point of view. (2) On the second level, the social interaction with others implies a virtual shifting and contrast of perspectives which helps to overcome a merely subject-centered worldview through participatory sense-making.
On this basis, the alteration of experience in beginning psychosis is phenomenologically described as a subjectivization of perception, resulting in an overall experience of self-centrality and derealization. Delusion then converts the disturbance of perception into a reframing of the perceived world, namely an assumed persecution by mundane enemies. Through this, a new sense-making is established, yet in a way that is fundamentally decoupled from the shared world. The possibility of intersubjective understanding is thus sacrificed for the new coherence of the delusion. Further implications of the loss of the intersubjective co-constitution of reality are analyzed, in particular related to disturbances of communication.

Top of page

Editor’s notes

First published in “Philosophy, Psychiatry & Psychology”, March 2020.

Full text

  • 1  Emphasis added. - The term “Each single experience” is my own translation from the original “Jede (...)

Normal convictions are formed in a context of social living and common knowledge. Immediate experience of reality survives only if it can fit into the frame of what is socially valid or can be critically tested …. Each single experience can always be corrected but the total context of experience is something stable and can hardly be corrected at all. The source for incorrigibility therefore is not to be found in any single phenomenon by itself but in the human situation as a whole, which nobody would surrender lightly. If socially accepted reality totters, people become adrift. (Jaspers 1968, p. 104)1

1. Introduction

1As Jaspers indicates in this quotation on incorrigibility, delusions may not be regarded as mere disorders of thinking, reasoning or reality-testing. Rather, they can only be explained on the background of the totality of a patient’s situation which is characterized by a dissolution of “socially accepted reality”. In contrast, the currently predominant psychiatric paradigm is based on a conception of the patient as an enclosed individual with a more or less clearly defined brain dysfunction. On this view, delusions seem to be the product of faulty neuronal information processing, or of “broken brains”. After all, delusions misrepresent reality, so they must somehow be “in the head”, usually being defined as “false beliefs based on incorrect inference about external reality” (APA 2000, p. 765).

2On the other hand, this can hardly be the whole story, for even the current definitions of delusion contain a cultural clause: convictions that seem bizarre from a Western viewpoint may well be shared with others in a corresponding cultural background and then give no justification for a diagnosis of delusion (APA 2013, p. 103). This already shows that the essence of delusion cannot be just a wrong content or representation of reality. In this paper, I will argue that delusions should rather be considered as intersubjective phenomena. Instead of reifying them as localizable states in the head of the patient, a phenomenological and enactive approach regards delusions as disturbances of intersubjectivity, namely on two levels:

  1. Delusions manifest themselves primarily as failures of communication: While interacting with the patient, one realizes that it is not possible to arrive at a shared definition of the situation through the usual giving and taking of reasons or mutual perspective-taking.

  2. On a deeper level, delusions may be regarded as a failure to co-constitute reality, that means, they are characterized by a disturbance of transcendental intersubjectivity as the condition of possibility for mutual understanding. This has been variously interpreted in terms of a loss of background certainties, common sense, we-intentionality, or basic trust (Rhodes & Gipps, 2008; Stanghellini, 2004; Fuchs, 2015a, b), or in the concept of schizophrenic quasi-solipsism (Sass 1994).

3The second characterization applies in particular to the delusions found in schizophrenia, which Jaspers called “delusions proper” (Jaspers, 1968, p. 96) or “primary delusions” (p. 98), and which he contrasted with the “delusion-like ideas” of patients with paranoia (today delusional disorder), psychotic mania or depression. The latter he regarded to be in principle psychologically motivated and understandable: In paranoia, for example, it is mainly suspicion and anxiety that lead to delusion of persecution; in mania, grandiose delusions are an expression of the underlying mood, and so on. In contrast, primary delusions involve a “transformation of basic experience which we have great difficulty in grasping” (p. 95). In recent phenomenological psychopathology, this difference has been interpreted in Heideggerian terms, contrasting “ontic delusions” (i.e., mundane delusions, belonging to the experienced world, such as in paranoia) with “ontological delusions” (referring to altered structures of subjectivity as the transcendental basis for experience itself) (Sass, 1992, 2014; Sass and Byrom, 2015; Parnas, 2004). It is the latter kind of delusions that I will deal with in the following.

4In order to develop an intersubjective and “inter-enactive” concept of delusions, I will first give an account of (a) the constitution of reality through enactive perception, (b) its co-constitution through “inter-enaction”, that means, through the communicative negotiation of viewpoints and mutual perspective-taking on the one hand, and through implicit or transcendental intersubjectivity on the other hand. For this account, I will use both phenomenological and enactive concepts. The guiding question is how the objectivity of perception and the shared reality are (co-)constituted. This will serve as a foundation for analyzing the disturbance of reality constitution in schizophrenic delusion.

5The account I will offer here is thus closely linked with recent work on the enactive constitution of a shared world (Stewart et al., 2011; Durt et al., 2017) and the application of enactivism to psychopathology (Drayson, 2009; Colombetti, 2013). Traces of such an intersubjective view can be found in various 20th century authors (e.g. Janet, 1926; Glatzel, 1981, pp. 167ff.). It is also clearly present in more recent works by Louis Sass (1992, 1994, 2014), who applies concepts from William James, Heidegger, and Wittgenstein to analyze the subjectivistic and sometimes quasi-solipsistic nature of schizophrenic delusions as a fundamental withdrawal from the shared practical world. Drawing from these authors, my approach puts particular emphasis on the assumption that the sense of reality is inherently bound up with our sensorimotor interaction with the environment and our interactions with others, that means, on the enactive and interenactive constitution of the shared world.

2. The objectivity of perception

2.1 Embodied engagement in the world

6The standard account of delusions regards them as “mistaken beliefs” about objective facts in the world that are held with incorrectable certainty. The underlying assumption is that there is an external reality which is only given to us through representations in our mind. This applies to perceptions (which are only images produced by the brain and could therefore also be called “true hallucinations”) as well as to beliefs about external states of affairs. This fundamental assumption of an internal representational domain separated from an external reality is challenged by the enactive approach to cognition (Varela, Thompson & Rosch, 1991; Thompson, 2007). From an enactive point of view, reality is not something predetermined and external, but continuously brought forth by a living being’s sensorimotor interaction with its environment. In the case of humans, this includes the constitution of a shared reality through social interactions such as taking part in conversations, mutual understanding and co-operative action. Importantly, both kinds of interaction over time also create fundamental bodily and mental structures, habits and certainties, which serve as a background of each encounter with concrete situations and enable our immediate, pre-reflective and practical grasp of the world. Let us look at these processes more closely.

7According to the enactive approach, living beings do not passively receive information from their environment which they then translate into internal representations. Rather, they constitute or enact their world through a process of sense-making: By actively searching and probing the environment for relevant cues - moving their head and eyes, touching a surface, walking towards a goal, grasping a fruit, etc. - they make sense of their surroundings. In other words, they constitute their experienced world or Umwelt through their ongoing sensorimotor interaction and embodied coping with the environment (Varela et al., 1991; Thompson, 2005, 2007; O’Regan and Noë, 2001). Hence, to “perceive” (from Latin per-cipere = to grasp through) is only possible for a living being that is able to actively move and to grasp for something. Even in seemingly pure perception, a living organism is not in opposition to the world, but always already entangled with it. But if the world is constituted for us through our own embodied and interactive sense-making, how can this entanglement result in the objectivity of perception which, after all, apparently presents us the objects themselves? How does perception overcome mere subjectivity?

  • 2  There are a number of other characteristics of embodied perception which contribute to the “realis (...)
  • 3  Efference copies from the brain motor areas “report” imminent movements to the sensory system, thu (...)

8An essential presupposition for this objectivity is the constant shifting of perspectives through self-movement (such as moving around an object, grasping and turning it, etc.) which creates changes and contrasts depending on one’s own action.2 For this, the body’s movement has to be accounted for in perception, that is, it has to be self-referential or self-given. Thus, the movements of the eye are taken into account and compensated by the sensory system through “efference copy” mechanisms, for otherwise the perceived surroundings would start to sway with every eye movement.3 Self-referential movement, or as it may also be termed, “agentive kinesthesia,” combined with the active shifting of one’s point of view, is a crucial means of establishing an objective relation to the environment, namely through an interconnection of the organism’s spontaneity and receptivity which mutually relativize and specify each other (on this, see also Blankenburg, 1991).

  • 4  This may sometimes lead to illusions, for example when searching for mushrooms and mistaking a shi (...)

9Importantly, this skilled sensorimotor interaction with the environment over time becomes part of the bodyʼs habitual knowledge and anticipations. With growing familiarity, the objects wished and searched for are already prefigured by the sensory system as perceptual schemas (Vorgestalten) which are projected into the environment, so to speak, to facilitate the identification of the objects.4 Moreover, what the environment enables and affords, and how it changes depending on our actions, is already anticipated in our perception. Thus, as Husserl (1950, pp. 91ff.) has shown, we perceive a house not just by looking at its visible side, but also by “appresenting” its invisible aspects, which we implicitly anticipate to behold once we move around the house. The actual aspect thus includes and reflects the totality of possible aspects making up the unity of the full object. Therefore, my experience of the reality of an object depends on a horizon of possible further experiences of this object - a horizon that is derived from my former dealings with it, but which is now implicitly given or “appresented”. Object permanence as acquired through sensorimotor interaction in early childhood (Piaget, 1955) is a crucial part of this: The objects will continue to exist also during my absence. This always present horizon enables my perception of the object itself instead of a merely momentary impression or image. Of course, my anticipating perception is constantly either confirmed or corrected by the ongoing interaction with the objects, that is, by further shifts of my perspective.

2.2 Intersubjective reality

10As we have seen, perception does not present images or appearances, but the full objects, for it is part of our embodied engagement in the world and not just passively being impressed. However, there is still another level of objectivity which is characteristic of human perception. For in perceiving the house, we experience it not only as an object of our possible engagement or skilled coping (moving towards it, opening the door, going upstairs, and so on), but also as independent of our present perception. The objects are not only there “for me,” in the immanence of my subjectivity, they are given as such. Berkeleyʼs “esse est percipi” certainly does not correspond to our experience of perception: Nobody would get the idea that the objects only emerged through his perception, and without it would vanish into nothingness. How is this independence possible?

11Husserl’s later answer to this question referred to the intersubjectivity of perception: The house that I see is also a possible object for others who could see it simultaneously from other sides. Thus, the object gains its actual objectivity, that is, its independence from my own perspective, through the implicit presence of a plurality of other perspectives. Husserls also speaks of an “apperceptive horizon of possible experiences, my own and those of others,” which turns the mere subjectivity of my experience into an “open intersubjectivity” (Husserl, 1973b, p. 107, p. 289; see also Zahavi, 1996, pp. 39ff.).Thus, there is again a horizon of perception, but one that is shared with others. The plurality of possible subjects corresponds to the plurality of aspects that the objects afford. Moreover, in perceiving the objects, I implicitly rely on their meaningfulness for others, that means, on the general structure of significances and affordances of our shared world. In perceiving, we always enact and inhabit a space that we share with others.

12More fundamentally, according to Husserl, objectivity depends on transcending my private sphere of subjectivity which primarily occurs in the encounter with the other (Husserl, 1973a, p. 110; 1973b, p. 277; on this, see also van Duppen, forthcoming). The other is always beyond my immanence, another sphere and center of perspectival consciousnes which remains inaccessible to me and thus constrains my own subjectivity. It is this alterity of the other which grounds my experience of objectivity, indeed my “perceptual faith” (Merleau-Ponty, 1968, p. 19) in a world that exists independent of my own perception. Because this intersubjectivity is implicit or transcendental (the “condition of possibility” of an objective reality to exist), the others need not be explicitly present - even Robinson Crusoe on his island saw it always “with othersʼ eyes”. In a fundamental sense, the objects and events in the world are always public, not private (Husserl, 1973c, p. 5); they belong to a shared world, even if they are only perceived by myself in the concrete case. This is also emphasized by Sartre, summing up Husserl’s view:

The Other is present in it [i.e., in the world] not only as a particular concrete and empirical appearance but as a permanent condition of its unity and of its richness. Whether I consider this table or this tree or this bare wall in solitude or with companions, the Other is always there as a layer of constitutive meanings which belong to the very object which I consider; in short, he is the veritable guarantee of the object’s objectivity.… Thus each object far from being constituted as for Kant, by a simple relation to the subject, appears in my concrete experience as polyvalent; it is given originally as possessing systems of reference to an indefinite plurality of consciousnesses; it is on the table, on the wall that the Other is revealed to me as that to which the object under consideration is perpetually referred - as well as on the occasion of the concrete appearances of Pierre or Paul. (Sartre, 1956, p. 233)

  • 5  Of course, Husserl’s concept of transcendental intersubjectivity may not simply be translated into (...)

13In enactive terms, this implicit or transcendental intersubjectivity may be interpreted as resulting from a history of “participatory sense-making” (De Jaegher & Di Paolo, 2007). From birth on, both the presence and the meaning of objects is continuously established through social interactions, particularly including situations of joint attention and joint practices of coping with the world. We learn to perceptually distinguish, to recognize and to handle objects be witnessing how others relate to them (Tomasello, 1999; Gallagher, 2008). Thus, reality is co-constituted or “interenacted” from the beginning. This intersubjective constitution has become a part of our habitual or implicit relation to the world, just like the sensorimotor interaction with the objects has become part of our embodied knowledge and perception (Fuchs 2016).5

14On this level of reality constitution, the equivalent to the self-referential movement and contrast of spatial viewpoints is social perspective-taking. Seeing the world with others’ eyes extends the bodily self-movement by adopting virtual perspectives and thus multiplies the possibilities of contrasting. Social situations with their multifarious meanings and ambiguities are in particular need of mutual exchange, communication and correction of viewpoints through taking the others’ perspective. Thus, the principle of the intersubjective constitution of reality is the relativization of one’s subjective point of view through social interaction with its alignment of perspectives. Although this alignment never comes to a definite conclusion, the possibility of further interaction opens up the horizon of achieving a mutual understanding that we anticipate in every encounter with others.

15The presupposition for these processes is obviously the human capacity of shared intentionality and perspective taking - that means, to transcend one’s own perspective and to grasp others’ intentions and viewpoints. This suspends the individual’s primary self-centrality and enables perspectival flexibility. Intersubjectivity in its full sense is thus based on the ability to oscillate between one’s egocentric perspective and an allocentric or decentered perspective. This crucial step of human cognitive development may also be summarized as reaching the “excentric position,” a term coined by German philosopher H. Plessner (1928) to denote a third or higher-level stance from which the integration of the ego- and allo-centric perspective is possible. It is also the position which enables a shared or “we-intentionality” of the members of a group, as being jointly directed towards a common object or action goal (Searle, 1995; Elsenbroich & Gilbert, 2014).

16This position is not only based on perspective-taking and decentering, but also includes an implicit, taken for granted background as the presupposition for a shared reality. It consists of the fundamental assumptions, “axioms of everyday life” (Straus, 1958) or bedrock certainties (Wittgenstein, 1969) that are shared by the members of a culture without necessarily being made explicit or verbalized. Common sense may be regarded as an expression of those basic certainties, but it also includes the shared habitualities, forms of interaction and “rules of the game” that are embodied rather than explicitly taught in the process of socialization. In the affective dimension, this background corresponds to a basic trust in the world and in others that develops from infancy through the interaction with the caregivers. The co-constitution of a shared reality, indeed our most fundamental “perceptual faith” in the experienced reality (Merleau-Ponty, 1968) crucially depends on this habitual and pre-reflective background which carries and supports all specific communication and negotiation of viewpoints within the lifeworld.

  • 6  Both levels and their corresponding forms of interaction with the environment may be distinguished (...)

17Let me summarize the above considerations: Perception transcends the centrality and boundedness of the subjective perspective by a decentering that occurs on two interrelated levels:6

  • On the first level, the sensorimotor interaction with the environment implies a mobility and multiplicity of perspectives that relativizes the momentary coupling of organism and environment.

  • On the second level, the social interaction with others implies a virtual shifting and contrast of perspectives which helps to overcome a merely subject-centered worldview through participatory sense-making.

18Thus, the single, momentary and subjective perception is put into perspective, receives depth and objectivity through a horizon of multiple other perspectives that is opened up and realized both through one’s sensorimotor and social interactions with the environment.

  • 7  This self-referentiality or self-givenness of action should not be confused with the self-referent (...)

19On both levels, the self-referentiality or self-givenness of the subject’s spontaneity and activity is crucial for gaining an objective view on the world, and that means, for the constitution of reality (Blankenburg, 1991).7 On the first level, a living being’s sensorimotor processes become transparent for reality inasmuch as it takes its own position and activity into account. This self-referentiality of movement enables the “mediated immediacy,” to use Hegel’s term, of the body’s relation to the environment. On the second level, the view of human beings on the shared world is clarified to the extent that they become aware of themselves in relation to others. For it is precisely the knowledge of myself in my relation to the environment which enables me to distinguish what is “for me” and what is “in itself,” and to grasp the objects as well as the others in their independence from my own subjectivity.

20Finally, on both levels an individual’s history of interactions is sedimented in his or her implicit memory, resulting in fundamental habitual structures:

  • On the first level, the body acquires the capacities of skillful coping and thus, a fundamental familiarity with the world. The horizon of possible perspectives and dealings with the objects is already anticipated or implied in each present perception.

  • On the second level, early socialization establishes the habitual structure of being-with-others, which manifests itself in an implicit or open intersubjectivity as well as in a basic trust in the common world. Through open intersubjectivity, human beings definitely transcend the subjectivity of their centric perspective and gain access to the shared, objective reality. For “objectivity” ultimately indicates that the objects are experienced as intersubjectively accessible, “as actually there for everyone” (Husserl, 1960, p. 91). This is why we implicitly perceive a given experiential object as transcending its momentary appearance. Human reality is therefore always co-constituted or interenacted through participatory sense-making, both implicitly and explicitly.

3. Subjectivization of perception in schizophrenia

21The significance of this analysis for various psychopathological phenomena seems quite obvious. For example, from an enactive point of view, hallucinations are only pseudo-perceptions which lack the sensorimotor cycles necessary for realistic perceiving on the first level. They may thus be regarded as products of the prefiguring activity of sensory or other brain systems which are projected into the field of awareness without resulting in sensorimotor interactions or perspectival change (this is why they are frequently experienced by the patients as “not really perceptions”). In other words, hallucinations are the result of a decoupling of brain activity and normal body-environment feedback. On the other hand, the second level of sense-making is concerned as well, inasmuch as the perceived (pseudo-)objects do not take part in the reality that is in principle accessible to others.

  • 8  In his seminal work Die beginnende Schizophrenie, the German psychiatrist Conrad (1958) termed thi (...)

22Turning to delusions, I will start my analysis by looking at the characteristic phenomena at the beginning of schizophrenic psychosis which amount to a radical subjectivization of perception. As is well known, in the predelusional atmosphere or “delusional mood” (Jaspers, 1968; Fuchs, 2005; Sass & Pienkos, 2013), the patients experience their surroundings as strangely unreal, as if they were seeing only artificial images instead of real objects. Objects look spurious, somehow manufactured or contrived; people seem to behave unnaturally, as if they were actors or impostors. It all feels like being in the center of an uncanny staging or pre-arranged scenes8:

Wherever you are looking, everything already appears unreal. The whole environment, everything becomes strange, and you get terribly frightened … Somehow everything is suddenly there for me, like being arranged for me. Everything around you suddenly refers to you. You are in the center of a plot like in front of backdrops. (Klosterkötter, 1988, p. 69; own transl.)

I’m constantly worrying about me. I would not say I’m persecuted, but everything feels oppressive. Take this table or these walls - they are strange. I guess everything looks phony! But it’s not only here, the walls in my living room also feel paper-like as if I was in a set. (Madeira et al., 2016)

  • 9  This experience is particularly accounted for by the neurobiological concept of the hypersalience (...)
  • 10  In these disorders, derealization is rather due to a loss of affective or bodily resonance, leadin (...)

23Such “Truman show” or “Matrix” symptoms, as they are frequently called by the patients themselves (Madeira et al., 2016), point to a radical change of the structure of perception, although no obvious disturbance of the sensory field may be detected. Instead, it is the intentional direction of the field that is reversed: Whereas the perceived objects formerly had their independent existence and kept their distance, they now start to refer to the patient, approaching him in an uncanny and oppressive way9. Everyday objects and situations lose their familiar meanings and seem to hint at something novel, yet still enigmatic and puzzling - perplexity, anxiety and increasing agitation is the patient’s usual reaction. The reason for all this is that perception no longer grasps the objects as such, but only presents their appearances (Fuchs, 2005). It has lost its intentional and decentering structure, and this is why the patient becomes the “center of the world”. The derealisation he experiences is thus quite different from a mere alienation of the surrounding world, as it may occur in neurotic or affective disorders.10 On the contrary, having lost their independent reality and neutrality, the objects are only there for the patient or seem arranged because of him. In other words, they lack their intersubjectively shared meanings and are no longer consensually given to everybody - which is, as Sass (1992, p. 283) also notes, one crucial mark of the real. Indeed they are no longer objects in the strict sense at all, but only pseudo-objects, appearances or images, set up for an unknown purpose.

24Not infrequently, this subjectivization of perception culminates in the impression that the existence of the objects or the world as a whole depends on the perceiver - as it were, a pathological form of Berkeleyʼs “esse est percipi (see also Sass, 1992, pp. 277f.):

Whenever I took my eyes of them [the hospital guards], they disappeared. In fact, everything at which I did not direct my entire attention seemed not to exist. (Landis, 1964, p. 90; quoted from Sass, l.c.)

At a party, everything seemed to originate from him or depend on him. (Parnas et al., 2005, p. 255)

If I perceive a door and then look away, then it’s almost as if the door ceases to exist. (Henriksen, 2011, p. 24)

  • 11  This does not mean that the child similarly perceives things as being dependent on him, for unlike (...)
  • 12  In “The paradoxes of delusion”, Sass also gives a number of case examples of withdrawal from senso (...)

25The last patient sometimes had the impression that she was the only person who really exists and that she was “responsible for the world moving on” a form of solipsistic self-centrality which frequently leads to a kind of “passive omnipotency,” as if the patients were able to determine the course of events or to move the world, yet without even knowing how (Conrad, 1958, p. 74; Fuchs, 2000, p. 143). The explanation is quite obvious: If perception has lost its objectivity, and this means, its implicit or open intersubjectivity, then the objects seem to move or even to exist only for me, or “by my grace”. Object permanence, acquired in early childhood and having become a transcendental condition of perceiving, is lost again.11 Moreover, as the German psychiatrist Matussek (1987) has shown in his analyses of delusional perception, patients are frequently captivated by minor details of the perceptual field and may fall into a veritable “rigidity of perception” (Wahrnehmungsstarre), unable to detach themselves from the object. This means that the cycles of sensorimotor interaction with the environment are impaired or arrested, thus contributing to the subjectivization of perception. Feelings of unreality usually deepen with increasing inaction and passivity (Sass, 1992, p. 297).12 This may culminate in the experience of being enclosed in one’s own perceptions, like in a subjective camera movie:

  • 13  Another example given by Sass already shows a delusional elaboration of this primary experience, d (...)

I saw everything I did like a film-camera. (Sass, 1992, p. 286)13

For me it was as if my eyes were cameras, and my brain would still be in my body, but somehow as if my head were enormous, the size of a universe, and I was in the far back and the cameras were at the very front. So extremely far away from the cameras. (de Haan & Fuchs, 2010, p. 329)

26Here the subject gets into a position outside the world; he literally becomes a homunculus within the head looking at his own perceptions like at projected images.

27In all these cases, we can see that perception does no longer transcend itself and reach the objects as such. Instead of perceiving the world, the subject experiences his experiences themselves; thus, he seems to be the “constituting center of the experiential universe” (Sass, 1992, p. 294) which revolves around him. The objectivity, i.e., the implicit intersubjective givenness of the world is lost, and the patients are enclosed in their own pseudo-perceptions like in a solipsistic inner world. The intersubjective constitution of objective reality is thus replaced by a radically subjectivist or idiosyncratic experience.

  • 14  Interestingly, schizophrenia patients have been found to show a poor deactivation of the Default M (...)

28An interesting analogy may also be seen in the structure of dream consciousness: here too, the subject is the ‘center of the world’. All things and events are displayed for him instead of being independent entities; they appear “out of the blue” and yet “just in time”, only to vanish into nothingness in the next moment. Moreover, the subject is delivered to the dream appearances in characteristic passivity - the practical sensorimotor interaction of body and environment is missing.14 At the same time, all situations show a self-referential significance (“tua res agitur”), even though this significance often remains enigmatic and mysterious. Though other persons usually play a major role in dreams, open intersubjectivity is lost: the dreamer has no excentric position from which he could relativize what happens by regarding it from another’s point of view. He is not able to distinguish what is ‘for me’ and what is‚ in itself, since he lacks the higher order knowledge of himself in relation to his environment.

4. Transition into delusion

29As a typical example for the transition of these disturbances into delusion, we can take the following case:

It seemed ever more unreal to me, like a foreign country …. Then it occurred to me that this was not longer my familiar environment … it might be no longer our house. Someone might set this up for me as a scenery. A scenery, or maybe it could be transmitted to me as a television play. … Then I touched the walls in order to check whether this was really a surface. (Klosterkötter, 1988, pp. 64f. own transl.)

30Again, the patient’s perception is subjectivized and thereby derealized: The natural attitude towards the world, the normally unquestioned “perceptual faith” is called in doubt. Since she is not aware of the disturbance of perception as such, it is the objects that seem to have changed, and she is testing their surface quality. In addition, however, the inversion of the intentional field already creates the impression of an external power being responsible for it. Getting more and more terrified, the patient was finally struck by the sudden evidence that a foreign secret service abused her for experimental purposes and projected fake images into her brain via rays (Klosterkötter, 1988). This insight felt like “scales falling from her eyes” and at least reduced the tension and terror she felt before, if only at the prize of a growing sense of persecution.

31The subjectivization of perception already prefigures the loss of intersubjectivity that we find in full-blown delusion. For it fundamentally shakes the basic trust in the shared, constant and reliable world - a shake whose terrifying effect may hardly be overestimated. On this background of an intolerable “ontological uncertainty,” the relieving and restabilizing effect of the delusion is based on the fact that it converts the transcendental disturbance of perception into an inner-worldly happening, namely an assumed persecution by mundane enemies or powers. In other words, the disturbance of perception is converted into a reframing of the perceived.

  • 15  Strictly speaking, it is only a pseudo-objectivity, because it is only constituted for the patient(...)
  • 16  Using Heidegger’s distinction of the „ontological“ (i.e. the fundamental existential level) and th (...)

32With this, however, a new objectivity is created: Precisely what had seemed uncanny, spurious and “made” before is now turned into the new reality of an actual, though concealed persecution and machination.15 Whereas before the perceived had lost its meaningful coherence, now everything is purposefully meant and arranged for the patient: Gazes observe her, secret cameras take shots of her, and the like. The inversion and self-centrality that resulted from perception losing its decentering returns in the omnipresent self-reference of alien powers that is typical for delusional ideation. Sense-making is thus reestablished (as the German Wahnsinn or “deluded sense” indicates), yet in a way that is fundamentally decoupled from the shared world16.

33We can summarize these fundamental changes in two steps, leading from (1) derealization to (2) delusion:

(1) Reality turns into appearance: Perception is subjectivized and presents only pseudo-objects.

(2) Appearance turns into new reality: Delusion converts this appearance into a new objectivity, implying that there is a reason for the changed environment (namely, the semblance is in fact created on purpose).

(1) Inversion of the perceptual field: The loss of decentering perception leads to solipstic self-centrality.

(2) → Inversion of intentionality: Delusion converts this self-centrality into self-referential intentions of hidden agents in the world. In other words, subjective or “transcendental” self-centrality is turned into mundane or social self-centrality.

  • 17  The concept of schizophrenia as a disturbance of basic, pre-reflective self-awareness or ‘ipseity’ (...)

34Not every schizophrenic delusion is based on the centralization of perceptual experience, however. Another, though related route to delusion derives from self-disturbances that affect the experience of one’s body, actions and stream of consciousness (Sass & Parnas, 2003; Parnas et al., 2005)17.Among these, I mention in particular experiences of passivity, namely the alienation of movements and thoughts: Bodily movements occur that are not initiated by the self, or thoughts emerge in the patient’s mind as if generated from outside. Patients may then experience themselves as robots or human machines, becoming the passive spectators of their body’s actions or their own thoughts (De Haan & Fuchs, 2010).

35From an enactive point of view, this may be explained by a loss of the self-referentiality or self-givenness of one’s own activity: Actions or thoughts appear in consciousness like alien fragments, only experienced in a deferred manner or ex post (on this, see Fuchs, 2013b; 2015c). The loss of self-agency results in an experience of disempowerment and passivity which again implies an inversion of intentionality and a self-centrality of the experiential field; instead of acting or thinking, the patient is being acted upon, or his thoughts are inserted. Delusions of control now turn these experiences into a mundane impact of external agents: The patient’s movements are steered by means of rays, thoughts are inserted through brain control, and the like. Such delusions usually involve a loss of boundaries between self and other, also termed Ich-Störungen or “ego-disorders” in German psychopathology. Frequently, patients use a physicalistic, technical or spatial vocabulary to describe these impacts, corresponding to the reification of their self-experience (for example, the well-known “influencing-machines”, Hirjak & Fuchs, 2010).

36Regardless whether being based on perceptual or more self-related disorders, with the formation and crystalization of the delusion a coherent and meaningful kind of reality is re-established. Delusion “makes sense,” however, in a fundamentally solipsistic way; for it turns the radical subjectivization and passivity of experience into a new, purposefully staged reality that is incompatible with the worldview of others. I will now further investigate this aspect.

5. The loss of open intersubjectivity

5.1 Breakdown of the “as if”

37The transition to the full-blown delusional conviction is marked by a typical change of attitude and language, namely a loss of the “as if”. At first the patients still maintain a critical distance to their experiences which is usually expressed in “as if” clauses: It only seems as if something extraordinary is going on (see also the above examples: “as if I was in a set,” and “as if the door ceases to exist”). This implies the preserved capacity to shift one’s perspective and take an external point of view from which what seems to be the case “cannot actually be true”. It indicates that the “excentric position” (Plessner, 1928) is still attainable. I quote another case vignette:

I could no longer think the way I wanted to … It was as if one could no longer think oneself, as if one were hindered from thinking. I had the impression that all that I thought were no longer my own ideas at all … as if I wouldn’t be the one who is thinking. I began to wonder whether I am still myself or an exchanged person. (Klosterkötter, 1988, p. 111; own transl., emphasis added)

38Again, the patient finally dropped the reservation of the “as if” and came to be convinced that a criminal organisation had implanted a chip in her brain to control her thoughts. The onset of delusions is thus marked by the breakdown of the “as if”. This implies not only a change in the degree of certainty but also the definitive loss of open intersubjectivity. For the possibility of calling one’s experience into doubt is still based on taking the perspective of the “generalized other” (Mead), that means, on an implicit intersubjectivity or common sense. The “as if” is the last connection to the shared world.

  • 18  Needless to say, this is not a step somehow „chosen“ by the patient; nor is it comparable with the (...)
  • 19  To a certain degree, this resembles the phenomena of asomatognosia, where a paralyzed limb is no l (...)

39However, the ambiguity of the “it seems as if” is too disturbing and tantalizing for the patient to be maintained for a longer time. Before long, the existential anxiety and the overwhelming urge for coherence of the perceptual field enforce a disambiguation, and the delusional conviction finally locks in place.18 The loss of the “as if” is therefore tantamount to a breakdown of the perspectival flexibility which would still enable the patient to take a general point of view and thus to gain a distance from the situation. It means a loss of the excentric position. Thus, the possibility of intersubjective understanding is sacrificed for the new coherence of delusional sense-making in an otherwise incomprehensible, deeply disturbing world. Once locked, this new and rigid coherence is further fortified through delusional elaboration: looking for additional evidence as well as systematically neglegting counter-evidence.19

40A manifestation of this rigidity is the exclusion of coincidence (Berner, 1978). The principle of coincidence normally allows us to neutralize a seemingly purposeful arrangement or simultaneity of events: “It seemed as if it was meant for me, but in fact it was only coincidence”. This presupposes shifting my primary, egocentric perspective on the situation to a neutral frame of reference in which I do not play a role. For the schizophrenia patient, however, the opposite is the case: It is precisely the normally irrelevant background elements that adopt a “telling,” sinister and threatening significance. They all manifest a concealed intentionality which aims at him. He can no longer neutralize these salient elements by attributing them to coincidence or to the “as if”, because the excentric position from which the principle of coincidence could even be taken into account is no longer attainable. One could also say that with the transition to delusion, the ‚as if‘ is given up as a formal reservation and instead shifts into the content of the delusion: What first seemed unreal, staged or artificial on the level of perception now becomes the actual staging, play-acting, and machination of the enemies - an intended ‘as if’.

5.2 Loss of the shared background

41If we now turn to the specific interaction with a deluded patient, we find a peculiar structure of non-understanding which is ultimately not due to a disagreement on particular statements or facts but to the fundamental assumptions on which the conversation itself is based. In normal verbal interactions, mutual understanding is achieved through reciprocal utterances, taking each other’s perspectives, misunderstanding and repair, clarifying meanings, and the like. In the process, we continuously shift between the ego- and the allocentric perspective. Deeper disagreement requires the give and take of reasons which may then lead to an increasingly consensual understanding or otherwise at least to an “agreement to disagree”. However, in the conversation with a deluded patient, all these processes remain strangely futile. When confronted with doubts or objections, the patient does not adequately respond. On the contrary, he will either assume a consensually perceived situation even though this is not at all the case from the other’s point of view (McCabe, Leudar & Antaki, 2004; Fuchs, 2015a); or he will justify his claims in a way that is not in the least sufficient for the interlocutor (“But how do you know they implanted a chip in your brain?” - “Well I just can feel it.”). He may even not attempt to make himself understood at all (“It’s pointless. I just know it, that’s all.”). In any case, the psychiatrist will experience what may be called a “gap of plausibilization”, that means, a blatant disproportion between the improbability of the patient’s statements and his attempts to justify them.

  • 20  This delusion may be found in the famous autobiographical report of Daniel Paul Schreber (1903/198 (...)

42If we then ask ourselves how it is possible that someone can maintain a belief as unusual as that (believing that a chip has been implanted in his brain, or that his biological sex has changed overnight, and the like), the question itself already shows that we have lost common ground. As Jaspers stated above, a delusion corresponds not to a single belief, but to a “total context of experience” which “can hardly be corrected at all. The source for incorrigibility therefore is not to be found in any single phenomenon by itself but in the human situation as a whole, which nobody would surrender lightly” (Jaspers, 1968, p. 104). However, this applies to our own situation as well, for it is always based on a bedrock of fundamental certainties (Wittgenstein, 1969) or background assumptions that we rely upon without explicitly awareness, but which we “would not surrender lightly”. This shared background is part of our everyday conduct of life, consisting of all the lived regularities, dispositions and assumptions that are neither propositions, representations nor rules. It is based on accumulated experience which has sedimented into our implicit knowledge and expectations, resulting, for example, in an everyday physics which tells us that humans just cannot fly out of windows in the air, or move far away trains by the power of their mind; or in an everyday biology which simply excludes that people’s sex could change overnight20, or that chips in their brains could be sending thoughts into their mind.

43We live and act on the background of these certainties not because we have ever concluded or made sure that they are true. They are just self-evident - part of our implicit intersubjectivity or common sense. To call them into doubt would be a pointless endeavor; indeed we would not - or even could not - rationally argue against it, but simply deem it “nonsense”. However, as Rhodes and Gipps (2008) have rightly argued, for the deluded patient, this background has fundamentally changed. With the radical subjectivization of his perception in delusional mood, the basic trust in the shared world has been shattered; common sense has lost its validity. As shown above, the emergence of delusion turns precisely this radical subjectivization and passivity of experience into a new objectivity, that means, into a new self-evidence. Now the patient cannot doubt these new certainties either - this would just not make sense for him. He literally lives in a different world: Moving far away trains is normal in a world where everything revolves around the self. Chips in brains are self-evident in a world of radical passivity. Changed biological sex is expectable in a world in which the self has lost its continuity. The new certainties are outside of any possibility of doubt or justification, no different from the certainties we rely upon in our world.

44From this follows that the patient’s delusional convictions are not rational conclusions or explanations. Delusions are not based on correct inferences from distorted primary experiences, as the so-called “empiricist” theory would have it (Maher, 1988; 1999). No abnormal experience whatsoever could make it rational to belief in thought insertion or brain chips, not because of the unusual content as such, but because the very notion of rationality implies the excentric point of view of the “generalized other,” and thus, in principle, intersubjective communicability. However, this general viewpoint is lost in delusion, and there is no private or solipsistic rationality instead. On the other hand, delusions are not based on irrational, faulty reasoning or wrong inferences either, as the “rationalist” approach assumes (e.g., “jumping to conclusions” on an insufficient evidence basis, Garety & Hemsley, 1994; Campbell, 2001). Such wrong conclusions are far too widespread to constitute the essence of delusion. Delusions are neither rational nor irrational; they are not theories, inferences or judgments about reality at all but self-evident revelations, which are only attained through a leap, and which first and foremost establish a new coherent reality.

  • 21  It is remarkable that this disconnection from the shared background is frequently restricted to th (...)
  • 22  This applies to full-blown delusions. It should be noted, however, that the patients are sometimes (...)

45This means, however, that the communication with a deluded patient, inasmuch as the delusion is concerned, has lost the background of implicit intersubjectivity and common sense on which mutual understanding is ultimately based.21 No rational argument whatsoever is valid any longer once the shared frame of reference is lost within which it could be claimed - it is just pointless. It is also for this reason that a psychiatrist usually does not need to falsify the patient’s statements in order to make a diagnosis. Their incongruence with our shared basic assumptions about the world suffices to recognize the delusional conviction as such - an incongruence that we realize with an unsettling, “vertiginous feeling” (Rhodes & Gipps, 2008, p. 299), but of which the patient himself is not even aware.22

46Since the objects and situations that delusional language refers to are not intersubjectively co-constituted but rather solipsistic (pseudo-)objects, one may even argue that we are dealing here with a kind of “private language”. For its meanings are no longer co-intended or shared but only valid within the idiosyncratic delusional framework. Correspondingly, Spitzer (1990) suggested that schizophrenic delusions should actually be considered as self-reports about private or inner states, and not as epistemic statements on factual matters in the public world (often the patients do not even claim intersubjective validity for their experiences). As is well known, Wittgenstein (1953/1968) considered a private language impossible, and one might indeed question whether the notion of language as an intersubjective realm of meaning is still applicable in this case. This would mean that delusions are indeed fundamentally “incomprehensible,” as Jaspers argued (1968, p. 98).

47Jaspers’ claim seems too strong, however: It would be overstated to say that the loss of co-intended meaning implies absolute incomprehensibility. After all, it is still possible to translate the patient’s utterances into our own language, provided that we take the transformation of the patient’s world into account, as I have tried to describe here. As Rhodes and Gipps have pointed out, in order to understand the patient’s delusional world, we have to “pursue the imaginative exercise of temporarily suspending those certainties that constitute the bedrock of our reason itself, certainties that are implicitly challenged by the delusional belief” (Rhodes & Gipps, 2008, p. 299). Blankenburg (1971) likened this task of the psychiatrist to the phenomenological epoche, that means, a methodic bracketing of our everday assumptions about the world.

5.3 Loss of the excentric position

  • 23  This has sometimes been termed “overmentalization”; see for example Montag et al. (2011). For a cr (...)

48Finally, we can also conceive the disturbance of communication in delusion as resulting from the partial loss of the excentric position that I have already described above as loss of the “as if”. For the alignment of different perspectives in the course of a conversation presupposes perspectival flexibility - transcending one’s own and taking the other’s perspective in order to grasp his intentions and making oneself understood. This flexibility is based on the excentric position. Granted, the patients are still able to imagine what others could think or intend (there is no basic defect of a “theory of mind”); they even take their presumed perspectives excessively, but in a way that all these perspectives seem to be directed back to the patients themselves.23 What they lack with regard to their delusion is the higher-order independent position from which they could relativize their experience of self-centrality (being alluded to, observed, persecuted by others, etc.). Taking the perspective of the real other is replaced by an illusionary self-referential perspective. The others are indeed only pseudo-subjects, figures or stereotypes for the delusional narrative rather than real counterparts whose perspective the patient could take.

49Another result of losing the excentric position is the phenomenon of transitivism described by Bleuler (1911/1950). Here, becoming “conscious of another consciousness” may threaten the patient with a loss of his or her self, as in the following cases:

When I look at somebody my own personality is in danger. I am undergoing a transformation and myself is beginning to disappear. (Chapman, 1966, p. 232)

The others’ gazes get penetrating, and it is as if there was a consciousness of my person emerging around me … they can read in me like in a book. Then I don’t know who I am any more. (Fuchs, 2000, p. 172)

50As I mentioned at the beginning, perspectival flexibility needs to be self-referential or self-given in order to present the perceived object or the other in independence from oneself. In transitivism, however, the patients are passively drawn into the other’s perspective and overwhelmed by their gazes or their mere presence (see Fuchs, 2015a). Having lost the independent position which mediates between ego- and allocentric perspective, they are caught in a short-circuit of perspectives, as it were, resulting in a melting of self and other. They are entangled in a self-referential and delusional view from the outside that dissolves their ego-boundaries. This short-circuit may also lead to the experience of thought-broadcasting: All the patientʼs thoughts are known to others; there is no difference between his mental life and that of others any more.

51Finally, a seemingly paradoxical result of losing the excentric position is the phenomenon of “double book-keeping,” also first identified by Bleuler (1911/1950, p. 378): Here, the everyday reality and the delusional reality are juxtaposed instead of one being sacrificed for the other. The patient now lives in two worlds at the same time, as it were: on the one hand the world of voices and delusions, and on the other hand the world as shared with others. For example, a patient may hear voices as clearly as the voice of the psychiatrist and believe them just as real, yet at the same time acknowledge that the psychiatrist does not hear them. A patient with grandiose delusion may be fully convinced that his coronation is imminent yet continue to do humble services on the ward, feeling little if any conflict between the two stances (Sass, 2014).

52In these cases, the integrating excentric position is lost too, but the delusional view does not replace the commonsensical perspective - they just coexist in different ontological domains without contiguity or overlap. However, this does not mean that the patient’s private reality would lose its delusional character and become a mere realm of his imagination or phantasy - on the contrary, its authority for the patient is even greater than that of consensual reality. Hence, the patients remain ambiguous, wavering between the demands of both domains. Thus Daniel Paul Schreber, in his famous “Memoirs of my nervous illness” (1903/1988), on the one hand develops his extended delusional system with utter conviction and zeal, while on the other hand denying that it claimed ordinary commonsensical realness: “I could even say with Jesus Christ: ‘My Kingdom is not of this world’; my so-called delusions are concerned solely with God and the beyond; they can therefore never in any way influence my behavior in any worldly matter” (Schreber, 1988, pp. 301f.). In his thorough analysis of the “Memoirs”, Sass notes: “Schreber’s claims seem, then, to involve two attitudes: one in which he accepts the essential innerness and privacy of his own claims, the other in which he assumes that they have some kind of objectivity and potential consensuality” (Sass, 1994, p. 55; see also Sass, 2014).

53One may conclude that in double bookkeeping, subjectivity and intersubjectivity have separated, yet the claim of the “generalized other” cannot be completely neglected. This confirms once more that delusions may not be understood without reference to the open intersubjectivity from which they have detached.

6. Summary and conclusion

54As I have shown in the first part, the constitution of reality is based on a polarity or a dialectical relation that we find on two levels:

  1. the dialectic between receptivity and spontaneity which mutually relativize each other, played out in the sensorimotor interaction of organism and environment.

  2. the dialectic between subjectivity and intersubjectivity, as played out in social interaction or participatory sense-making.

55On both levels, the self-referentiality or self-givenness of one’s own relation to the environment is a crucial presupposition for the decentering that is necessary to transcend pure subjectivity and to constitute an independent reality. In human perception, both levels are inseparably interlinked and, through a twofold decentering, they together enable the objectivity of perception. We live in a world of objects, because we are involved in its constitution through our sensorimotor engagement. And we live in a shared objective reality because we continuously “interenact” it through our joint activities and participatory sense-making. Moreover, both phylogenetically and ontogenetically, this enactive and intersubjective (co-)constitution of reality has become a transcendental structure of human perception itself: Even in the absence of others, my perception always implies their possible presence, as an implicit or open intersubjectivity.

  • 24  This “ontological unsecurity” (Laing, 1959) is manifested in the premorbid self-disorders frequent (...)

56Thus, there exists a close intertwinement of the enactive and the interenactive constitution of reality, which characterizes the transcendental structure of human perception. This structure is realized in the course of sensorimotor and social interactions in early childhood, and is also in place in schizophrenia patients before the first manifestation of the illness, even though in an unstable and fragile way.24 I have analyzed how in beginning psychosis the decentering structure of perception breaks down, leading to a subjectivization of the perceptual field, to an inversion of intentionality, and thus to a fundamental derealization that is the condition for delusion formation in the further course.

  • 25  Various etiological hypotheses have been proposed, of which only some shall be mentioned:
    A neurob (...)

57Which precise pathogenetic pathways lead to the loss of objectifying perception, is not clarified so far; to address this complex issue was not the aim of the paper.25 In any case, once this structure collapses in beginning psychosis, the objectivity of perceived reality is shaken or lost, resulting in an overall experience of self-centrality, even though the level of sensorimotor interaction with the environment is usually not conspicuously affected. All the more, the intersubjective co-constitution of meaning is now severely disturbed, and in delusion this co-constitution is finally sacrificed in favor of a new coherence of the perceptual and intentional field. As I have pointed out, the loss of the “as if” manifests this decisive step of a decoupling of subjectivity from open intersubjectivity. It is equivalent to a loss of the excentric position or perspectival flexibility (at least inasmuch as the domain of delusion is concerned) and to a fundamental alienation from the commonsensical background necessary for shared intentionality and communication within the lifeworld.

58Interestingly, we can find an “interenactive” account of delusions avant la lettre already in Pierre Janet who pointed out that a belief essentially implies a certain readiness to act:

59A belief is ultimately a promise of action. To believe in the existence of the Arc of Triumph implies being able to show it to a someone, to drive him there, and to experience a disappointment, should it turn out not to be there. On the other hand, … [a delusional belief] belongs to the verbal acts that cannot be transferred into actions. (Janet, 1926, p. 95; quoted after Parnas, 2004, p. 156)

  • 26  In contrast to delusion-like ideas or “ontic delusions” in paranoia (see introduction above), prim (...)

60As Janet’s example aptly shows, the readiness to act which characterizes a normal belief is also inherently intersubjective. What we believe to be the case, even more what is part of our immediate “perceptual faith” in reality, must not only in principle be accessible to others; it should always be open for a shared practical engagement as well. However, since the delusional belief is based on a subjectivized and passive perception partly decoupled from the cycles of sensorimotor interaction, it does not imply adequate action readiness (at least not in a commonsensical way26). Even more, it does not enable an interenactive relation to a shared reality: What the patients experience (being implanted chips in their brains, hearing voices, and the like) cannot be “shown” to others. As Sass notes, schizophrenia patients rarely act as if their delusional convictions belonged to a practical and consensual world. They rather seem to belong to a special domain which is “sealed-off from real-world action” (Sass, 1992, p. 274f.). Therefore, they usually do not even assume that it is amenable to intersubjective examination or that it may as well happen to others. As we have seen, the two worlds frequently remain completely separated from each other through “double bookkeeping”. One might indeed argue that the so-called “delusional beliefs” are not beliefs in the epistemic sense at all, for they lack the basis of a shared intentional relation to the world.

61Although there are important differences, we may finally conclude that the fundamental alteration of experience at the roots of schizophrenic delusions resembles in many respects the state of dreaming: Here too, the shared world is replaced by a private world of figments and imaginations that are not recognized as such and lack the reservation of the “as if”. They also lack the open intersubjectivity of an experience that would in principle be accessible to everyone, thus transcending mere appearances. It is a world which Heraclit famously called the ídios kósmos of the dreamer, in contrast to the koinós kósmos of daytime:

The waking have one common world, but the sleeping turn aside, each into a world of his own. (Diels & Kranz, 1951, fragment B 89)

Top of page


American Psychiatric Association (APA) (2000). Diagnostic and statistical manual of mental disorders: DSM 4. (4th edition). Arlington VA: American Psychiatric Association;

American Psychiatric Association (APA) (2013). Diagnostic and statistical manual of mental disorders: DSM 5. (5th edition). Arlington VA: American Psychiatric Association;

Berner P. (1978). Psychopathologische Wahnforschung und psychiatrische Hypothesenbil-dung. Nervenarzt, 49, pp. 147-152;

Blakemore S. J., Smith J., Steel R., Johnstone E. C. & Frith C. D. (2000). The perception of self-produced sensory stimuli in patients with auditory hallucinations and passivity experiences: evidence for a breakdown in self-monitoring. Psychological Medicine, 30, pp.1131-1139;

Blankenburg W. (1971). Der Verlust der natürlichen Selbstverständlichkeit (The loss of natural self-evidence). Berlin: Springer;

Blankenburg W. (Ed.) (1991). Wahn und Perspektivität. Störungen im Realitätsbezug des Menschen und ihre Therapie. Stuttgart: Ferdinand Enke Verlag;

Bleuler E. (1911/1950). Dementia praecox or the group of schizophrenias (J. Zinkin, Trans.). New York: International University Press.;

Bliksted V. Fagerlund B., Weed E., Frith C. & Videbech P. (2014). Social cognition and neurocognitive deficits in first-episode schizophrenia. Schizophrenia Research, 153, pp. 9-17;

Bourque F., Van der Ven E. & Malla A. (2011). A meta-analysis of the risk for psychotic disorders among first-and second-generation immigrants. Psychological medicine, 41, pp. 897-910;

Campbell J. (2001). Rationality, meaning, and the analysis of delusion. Philosophy, Psychiatry, & Psychology, 8, pp. 89-100;

Cantor-Graae E. & Selten J. P. (2005). Schizophrenia and migration: A meta-analysis and review. American Journal of Psychiatry, 162, pp. 12-24;

Chapman J. (1966). The early symptoms of schizophrenia. British Journal of Psychiatry, 112, pp. 225-251;

Coate M. (1965). Beyond all reason. Philadelphia, New York: Lippincott;

Colombetti G. (2013). Psychopathology and the enactive mind. In B. Fulford et al. (Eds.) Oxford Handbook of the Philosophy of Psychiatry, pp. pp. 1083-1102. Oxford: Oxford University Press;

Conrad, K. (1958). Die beginnende Schizophrenie: Versuch einer Gestaltanalyse des Wahns. Stuttgart: Thieme;

De Haan S. & Fuchs T. (2010). The ghost in the machine: Disembodiment in schizophrenia. Two case studies. Psychopathology, 43, pp. 327-333;

De Jaegher H. & Di Paolo E. (2007). Participatory sense-making: an enactive approach to social cognition. Phenomenology and the Cognitive Sciences, 6, pp. 485-507;

Diels H., Kranz W. (1951) Die Fragmente der Vorsokratiker. Griechisch und Deutsch von Hermann Diels. Herausgegeben von Walther Kranz. Hildesheim: Weidmann;

Durt C., Tewes C. & Fuchs T. (Eds.) (2017). Embodiment, enaction, and culture. Investigating the constitution of the shared world. Cambridge/Mass.: MIT Press;

Elsenbroich C. & Gilbert N. (2014). We-intentionality. In C.Elsenbroich, N. Gilbert (Eds.) Modelling Norms, pp. 185-197. Dordrecht: Springer;

Fearon P., Kirkbride J. B., Morgan C., Dazzan P., Morgan K., Lloyd T., … Murray R. M (2006). Incidence of schizophrenia and other psychoses in ethnic minority groups: results from the MRC AESOP Study. Psychological Medicine, 36, pp. 1541-50;

Freud S. (1924/1961). The loss of reality in neurosis and psychosis. Trans. J. Stratchey. In The Standard Edition of the Complete Psychological Works of Sigmund Freud 19, pp. 181-187. London: Hogarth Press;

Frith C. D. (1992) The cognitive neuropsychology of schizophrenia. Hillsdale: Earlbaum;

Frith C. D. (2004) Schizophrenia and theory of mind. Psychological Medicine, 34, pp. 385-389;

Fuchs T. (2000). Psychopathologie von Leib und Raum. Phänomenologisch-empirische Untersuchungen zu depressiven und paranoiden Erkrankungen. Darmstadt: Steinkopff;

Fuchs T. (2005). Delusional mood and delusional perception - A phenomenological analysis. Psychopathology, 38, pp. 133-139;

Fuchs T. (2013a). The phenomenology and development of social perspectives. Phenomenology and the Cognitive Sciences, 12, pp. 655-683;

Fuchs T. (2013b). Temporality and psychopathology. Phenomenology and the Cognitive Sciences, 12, pp. 75-104;

Fuchs T. (2013c). Depression, intercorporality and interaffectivity. Journal of Consciousness Studies, 20, pp. 219-238;

Fuchs T. (2015a). Pathologies of intersubjectivity in autism and schizophrenia. Journal of Consciousness Studies, 22, pp. 191-214;

Fuchs T. (2015b). The intersubjectivity of delusions. World Psychiatry, 14, pp. 178-179;

Fuchs T. (2015c). From self-disorders to ego disorders. Psychopathology, 48, pp. 324-331;

Fuchs T. (2016). Embodied knowledge - embodied memory. In S. Rinofner-Kreidl, & H. Wiltsche (Eds.) Analytic and Continental Philosophy. Methods and Perspectives. Pro-ceedings of the 37th International Wittgenstein Symposium (pp. 215-229). Berlin: De Gruyter;

Gallagher S. (2004). Neurocognitive models of schizophrenia: A neurophenomenological critique. Psychopathology, 37, pp. 8-19;

Gallagher S. (2008). Intersubjectivity in perception. Continental Philosophy Review, 41, pp. 163-178;

Garety P. & Hemsley D. (1994). Delusions. Oxford: Oxford University Press;

Henriksen M. G. (2011). Understanding schizophrenia. Investigations in phenomenological psychopathology. PhD Thesis, Faculty of Health Sciences, University of Copenhagen;

Hirjak D. & Fuchs T. (2010). Delusions of technical alien control: A phenomenological description of three cases. Psychopathology, 43, pp. 96-103;

Holst E. v. & Mittelstaedt H. (1950). Das Reafferenzprinzip. Naturwissenschaften, 37, pp. 464-476;

Husserl E. (1950). Ideen zu einer reinen Phänomenologie und phänomenologischen Psychologie. Vol. I. Allgemeine Einführung in die reine Phänomenologie. Husserliana III. Den Haag: Martinus Nijhoff;

Husserl E. (1960). Cartesian Meditations. An Introduction to Phenomenology. Trans. D. Cairns. The Haag: Martinus Nijhoff;

Husserl E. (1973a). Zur Phänomenologie der Intersubjektivität. 1905-1920: Erster Teil. Den Haag: Martinus Nijhoff;

Husserl E. (1973b). Zur Phänomenologie der Intersubjektivität. 1921-1928: Zweiter Teil. Den Haag: Martinus Nijhoff;

Janet P. (1926). De l’angoisse à l’ecstase. Paris: Felix Alcan;

Jaspers K. (1968). General Psychopathology (7th edition) (J. Hoenig & M.W. Hamilton, Trans.). Chicago, IL: University of Chicago Press;

Jeannerod M., Farrer C., Franck N., Fourneret P., Posada A., Daprati E. & Georgieff N. (2003). Action recognition in normal and schizophrenic subjects. In Kircher, T., & David, A. (Eds.) The self in neuroscience and psychiatry, (pp. 380-406).Cambridge, UK: Cambridge University Press;

Kapur S. (2003). Psychosis as a state of aberrant salience: a framework linking biology, phenomenology, and pharmacology in schizophrenia. American Journal of Psychiatry, 160, pp. 13-23;

Klosterkötter J. (1988). Basissymptome und Endphänomene der Schizophrenie. Berlin Heidelberg New York: Springer;

Laing R. D. (1959). The Divided Self. An Existential Study in Sanity and Madness. London: Harmondsworth;

Landis C. (1964). Varieties of psychopathological experience. New York: Holt, Rinehart & Winston;

Madeira L., Bonoldi, I., Rocchetti, M., Brandizzi, M., Samson, C., Azis, M., … Fusar-Poli, P. (2016). Prevalence and implications of Truman symptoms in subjects at ultra high risk for psychosis. Psychiatry research, 238, pp. 270-276;

Maher B. A. (1988). Anomalous experience and delusional thinking: The logic of explanations. In Oltmanns, T. F. & Maher B. A. (Eds.) Delusional beliefs (pp. 15-33). Hoboken, NY: John Wiley & Sons;

Maher B. A. (1999). Anomalous experience in everyday life: Its significance for psychopathology. The Monist, 82, pp. 547-570;

Matussek P. (1987). Studies in delusional perception. In Cutting, J., & Shepherd, M. (Eds.) The clinical roots of the schizophrenia concept: Translations of seminal European contributions on schizophrenia (pp. 89-103). Cambridge, UK: Cambridge University Press;

McCabe R., Leudar I. & Antaki C. (2004). Do people with schizophrenia display theory of mind deficits in clinical interactions? Psychological Medicine, 34, pp. 401-412;

Merleau-Ponty M. (1968). The visible and the invisible. Evanston: Northwestern University Press;

Montag C., Dziobek I., Richter I. S., Neuhaus K., Lehmann A., Sylla R. & Gallinat J. (2011). Different aspects of theory of mind in paranoid schizophrenia: Evidence from a video-based assessment. Psychiatry research, 186, pp. 203-209;

O’Regan J. K. & Noë A. (2001). A sensorimotor account of vision and visual consciousness. Behavioural and Brain Sciences, 24, pp. 939-1011;

Parnas J. (2004). Belief and pathology of self-awareness. A phenomenological contribution to the classification of delusions. Journal of Consciousness Studies, 11, pp. 148-161;

Parnas J. & Henriksen M. G. (2014). Disordered self in the schizophrenia spectrum: a clinical and research perspective. Harvard Review of Psychiatry, 22, pp. 251-265;

Parnas J., Moeller P., Kircher T., Thalbitzer J., Jannson L., Handest P. & Zahavi D. (2005). EASE: Examination of Anomalous Self-Experience. Psychopathology, 38, pp. 236-258;

Parnas J. & Sass L. A. (2001). Solipsism, self, and schizophrenic delusions. Philosophy, Psychiatry & Psychology, 8, pp. 101-120;

Piaget J. (1955). The Child’s Construction of Reality. London: Routledge and Kegan Paul;

Pinkham A. E. (2014). Social cognition in schizophrenia. Journal of Clinical Psychiatry, 75, Suppl. 2, pp. 14-19;

Plessner H. (1928/1981). Die Stufen des Organischen und der Mensch. Gesammelte Schriften IV. Frankfurt am Main: Suhrkamp;

Pomarol-Clotet E., Salvador R., Sarro S., et al. (2008). Failure to deactivate in the prefrontal cortex in schizophrenia: dysfunction of the default mode network? Psychological Medicine, 38, 1185-93;

Pynn L. K. & DeSouza J. F. (2013). The function of efference copy signals: implications for symptoms of schizophrenia. Vision Research, 76, pp. 124-133;

Rhodes J. & Gipps R. G. T. (2008). Delusions, certainty, and the background. Philosophy, Psychiatry, & Psychology, 15, pp. 295-310;

Salice A. & Henriksen M. G. (2015). The Disrupted ‘We’: Schizophrenia and Collective Inten-tionality. Journal of Consciousness Studies, 22, pp. 145-171;

Sartre J. P. (1956). Being and Nothingness (Hazel E. Barnes, Trans.). New York: Philosophical Library;

Sass L. A. (1992). Madness and modernism: Insanity in the light of modern art, literature, and thought. New York: Basic Books;

Sass L. A. (1994). The paradoxes of delusion. Wittgenstein, Schreber, and the schizophrenic mind. Ithaka, London: Cornell;

Sass L. A. (2014). Delusion and double book-keeping. In T. Fuchs, & T. Breyer (Eds.) Karl Jaspers’ philosophy and psychopathology (pp. 125-147). New York: Springer;

Sass L. A. & Byrom G. (2015). Phenomenological and neurocognitive perspectives on delusions: a critical overview. World Psychiatry, 14, pp. 164-73;

Sass L. A. & Parnas, J. (2003). Schizophrenia, consciousness, and the self. Schizophrenia Bulletin, 29, pp. 427-444;

Sass, L. A. & Pienkos, E. (2013). Delusion: the phenomenological approach. In B. Fulford et al. (Eds.) Oxford Handbook of the Philosophy of Psychiatry (pp. 632-657). Oxford: Oxford University Press;

Schreber D. P. (1903/1988) Memoirs of my nervous illness. Transl. I. Macalpine, R. A. Hunter. Cambridge, MA: Harvard University Press;

Sechehaye M. (1994). Autobiography of a schizophrenic girl: The true story of “Renée” (F. Conroy, Trans.). New York: Meridian;

Searle J. (1995). The construction of social reality. New York: The Free Press;

Spitzer M. (1990). On defining delusions. Comprehensive Psychiatry, 31, pp. 377-397;

Stanghellini G. (2004). Disembodied spirits and deanimatied bodies: The psychopathology of common sense. Oxford: Oxford University Press;

Stephan K. E., Friston K. J. & Frith C. D. (2009). Dysconnection in schizophrenia: from abnormal synaptic plasticity to failures of self-monitoring. Schizophrenia Bulletin, 35, pp. 509-527;

Stewart J., Gapenne O. & Di Paolo E. (Eds.) (2011) Enaction: towards a new paradigm for cognitive science, pp. 361-385, Cambridge, MA: MIT Press;

Straus E. (1958). Aesthesiology and hallucinations. In R. May E. Angel & H. F. Ellenberger (Eds.) Existence: A new dimension in psychiatry and psychology (pp. 139-169). New York: Basic Books;

Thompson E. (2005). Sensorimotor subjectivity and the enactive approach to experience. Phenomenology and the Cognitive Sciences, 4, pp. 407-427;

Thompson E. (2007). Mind in life: Biology, phenomenology, and the sciences of mind. Cambridge, MA: Harvard University Press;

Tomasello M. (1999). The cultural origins of human cognition. Cambridge, MA: Harvard University Press;

Van Duppen Z. (2016). The phenomenology of hypo- and hyperreality in psychopathology. Phenomenology and the Cognitive Sciences, 15, pp. 423-441;

Van Duppen Z. (forthcoming). The intersubjective dimension of schizophrenia. Philosophy, Psychiatry, & Psychology;

Varela F. J., Thompson E. & Rosch E. (1991). The embodied mind: Cognitive science and human experience (6th ed.). Cambridge, MA: MIT Press;

White T. P., Joseph V., Francis S. T., Liddle P. F. (2010). Aberrant salience network (bilateral insula and anterior cingulate cortex) connectivity during information processing in schizophrenia. Schizophrenia Research, 123, pp. 105-115;

Wittgenstein L. (1953/1968). Philosophical investigations (3rd ed.) (G. E. M. Anscombe, Trans.). New York: Macmillan;

Wittgenstein L. (1969). On Certainty. Oxford: Basil;

Zahavi D. (1996). Husserlʼs intersubjective transformation of transcendental philosophy. Journal of the British Society for Phenomenology, 27, pp. 228-245.

Zammit S., Lewis G., Rasbash J., Dalman C., Gustafsson J. E. & Allebeck P. (2010). Individuals, schools, and neighborhood. A multilevel longitudinal study of variation in incidence of psychotic disorders. Archives of General Psychiatry, 67, pp. 914-922.

Top of page


1  Emphasis added. - The term “Each single experience” is my own translation from the original “Jede einzelne Erfahrung,” whereas Hoenig’s translation “Individual experience” is misleading, to say the least.

2  There are a number of other characteristics of embodied perception which contribute to the “realism” of experience, but are left out of account here. Among them are the establishment of shape and colour constancy, the intermodal integration of the different senses, the resistance of objects, and others. See also O’Regan and Noë (2001) and van Duppen (2016).

3  Efference copies from the brain motor areas “report” imminent movements to the sensory system, thus preparing it for the change in the perceptual field resulting from the body’s action (cf. Holst & Mittelstaedt, 1950). Interestingly, if one moves one’s eyeball externally (e.g., by softly pressing it with the finger from the side, with the other eye closed), the perceived environment in fact starts to sway. In this case, the eye movement is not self-referential.

4  This may sometimes lead to illusions, for example when searching for mushrooms and mistaking a shiny leave for a mushroom, or when expecting to meet an acquaintance and mistaking another person in the distance for him.

5  Of course, Husserl’s concept of transcendental intersubjectivity may not simply be translated into a developmental account of learning about the world from others. If I refer to the genetic aspect of intersubjectivity, this is not to say that the transcendental level can be reduced to a history of accumulated learning. However, since human beings are obviously not born as transcendental subjects, this level has somehow to be reached in the course of early development and social interaction, though this does not have to be a gradual progression or accumulation (see also Fuchs, 2013a; van Duppen, forthcoming).

6  Both levels and their corresponding forms of interaction with the environment may be distinguished conceptually, but their development in early childhood of course proceeds in close intertwinement.

7  This self-referentiality or self-givenness of action should not be confused with the self-referentiality or self-centrality that is characteristic of paranoid and delusional states (see below). The former is related to the organism itself, the latter to the perceived environment.

8  In his seminal work Die beginnende Schizophrenie, the German psychiatrist Conrad (1958) termed this first stage of delusional development the “trema,” a Greek term for the “stage fright” that actors may feel before the play starts.

9  This experience is particularly accounted for by the neurobiological concept of the hypersalience syndrome (Kapur, 2003). It may also be illustrated by Sechehayeʼs quotation of her patient Renée: “This existence accounted for my great fear. In the unreal scene, in the murky quiet of my perception, suddenly ‘the thing’ sprang up. The stone jar, decorated with blue flowers, was there facing me, defying me with its presence, with its existence. To conquer my fear I looked away. My eyes met a chair, then a table; they were alive, too, asserting their presence. I attempted to escape their hold by calling out their names. I said, ‘chair, jug, table, it is a chair’” (Sechehaye, 1994, p. 56).

10  In these disorders, derealization is rather due to a loss of affective or bodily resonance, leading to a lack of attractive or impressive qualities of the environment. Objects then lose their allure and rather look hollow, empty or dead instead of ominous, uncanny or strangely significant (on this, see Fuchs, 2013c).

11  This does not mean that the child similarly perceives things as being dependent on him, for unlike the schizophrenia patient, he lacks a reflexive awareness of his own perceiving. In general, as Sass has also emphasized, the subjectivized perception in schizophrenia must be distinguished from infantile egocentrism (Sass, 1992, 277).

12  In “The paradoxes of delusion”, Sass also gives a number of case examples of withdrawal from sensorimotor activity as being connected with psychotic experiences (Sass, 1994, 34ff.) and writes: „The more one stares at things, the more they may seem to have a coefficient of subjectivity, the more they may come to seem ‚things seen‘“, that means, mere appearances. On the other hand, „the act of moving a physical object also confirms one’s own experience of activity and efficacy, thus precluding a sense of passivization as well as subjectivization“ (l.c., 35f.).

13  Another example given by Sass already shows a delusional elaboration of this primary experience, dropping the „as-if“ account: „I was myself a camera. The views of people that I obtained through my own eyes were being recorded elsewhere to make some kind of three-dimensional film“ (Coate, 1965, 101; quoted from Sass, l.c.).

14  Interestingly, schizophrenia patients have been found to show a poor deactivation of the Default Mode Network in the brain (which is normally active in introverted, self-referential states such as day-dreaming) even when they are attending to external stimuli (Pomarol-Clotet et al. 2008; White et al., 2010). This suggests that a dreamlike or subjectivized state can be sustained in these patients even during world-directed activity.

15  Strictly speaking, it is only a pseudo-objectivity, because it is only constituted for the patient, thus lacking implicit intersubjectivity.

16  Using Heidegger’s distinction of the „ontological“ (i.e. the fundamental existential level) and the „ontic“ (the inner-worldly happenings), Sass rightly describes this process as the transformation of „a fundamentally ontological experience […] into one that is at least quasi-ontic in nature“ (Sass, 1992, 294). However, it seems that he takes this transformation to be only the result of using the (insufficient) everyday language and context to describe the ontological change; the patient lacks the philosophical insight, so-to-speak, to stay on the ontological level of description, resulting in a “confusion of ontic with ontological” (l.c., 293). By contrast, I regard the transition into the “ontic” delusion as the crucial means by which a coherent inner-worldly experience is re-established. In other words, a new, rigid framework locks in, which resists any possible questioning or returning to the ontological level. In this stabilization consists the function of delusion, and it explains its rigidity.

17  The concept of schizophrenia as a disturbance of basic, pre-reflective self-awareness or ‘ipseity’ developed by Parnas and Sass cannot be dealt with here. Recently, van Duppen (forthcoming) has proposed the concept of „open subjectivity“ as a common core for both the subjective and intersubjective dimension of schizophrenic disturbances. This fills an important gap in the phenomenological account of schizophrenia as a disorder of both self and intersubjectivity.

18  Needless to say, this is not a step somehow „chosen“ by the patient; nor is it comparable with the ignoring or repression of unpleasant aspects of reality in neurotic disorder. Freud’s explanation of psychosis as “wishful replacement of reality” (Freud, 1924) seems incompatible with the terror that many schizophrenia patients experience in their delusions and hallucinations (this does not preclude that a psychodynamic approach might have some limited value in explaing certain contents of hallucinations and delusions). One might rather think of attributing the turn into delusion to an inherent tendency of consciousness towards coherence, or, in terms of dynamical systems theory, think of an “unusual attractor” of the neuronal system which, once snapped in, may not be left again.

19  To a certain degree, this resembles the phenomena of asomatognosia, where a paralyzed limb is no longer recognized as one’s own, or hemilateral neglect, where a whole side of space is no longer perceived or even taken into account as a result of damage to the contralateral brain hemisphere. In such neurological cases, the coherence of the experienced world is maintained at the prize of “sacrificing” part of one’s body or part of the world which are then no longer accessible to consciousness.

20  This delusion may be found in the famous autobiographical report of Daniel Paul Schreber (1903/1988; see below).

21  It is remarkable that this disconnection from the shared background is frequently restricted to the delusional content, while other domains of communication and understanding may remain intact. The delusion crystallizes around a core theme which establishes meaning and coherence with regard to the fundamental perceptual and self-disturbances. Once this delusional schema is fixed (“plugging the leak,” as it were), other areas of life may remain unaffected.

22  This applies to full-blown delusions. It should be noted, however, that the patients are sometimes still aware of the improbability of their experiences for others. This may result in a “double bookkeeping” (see below).

23  This has sometimes been termed “overmentalization”; see for example Montag et al. (2011). For a critique of Frith’s (1992, 2004) concept of a lack of “theory of mind” as an overall explanatory framework for schizophrenia, see Gallagher (2004). This does not exclude problems of social cognition and perspective-taking with regard to real others in schizophrenia; see for example, Bliksted, Fagerlund, Weed, Frith & Videbech, 2014; Pinkham 2014.

24  This “ontological unsecurity” (Laing, 1959) is manifested in the premorbid self-disorders frequently dating back into the patientsʼ childhood (see Parnas & Henriksen, 2014 for a review). Whether this instability may be related to disorders of early brain maturation and connectivity (Stephan, Friston & Frith, 2009) remains to be further investigated..

25  Various etiological hypotheses have been proposed, of which only some shall be mentioned:
A neurobiological disturbance of enactive perception on the sensorimotor level could play a major role, for example, a failure of efference copy mechanisms (Pynn & DeSouza, 2013).
The hypersalience of perceptual impressions may be caused by a dopaminergic hyperfunction in the brain (Kapur, 2003).
The lack of self-givenness of perception may be due to the basic disorders of self-awareness or “ipseity” that Parnas and Sass have claimed as a fundamental disturbance of schizophrenia (Parnas & Sass, 2001; Sass & Parnas, 2003; on this connection, see also Fuchs, 2015c).
Another important condition could be a loss of basic trust and familiarity with the shared life world, as suggested by the increased incidence of schizophrenia in migrant and otherwise marginalized populations (Fearon et al., 2006; Cantor-Graae & Selten, 2005; Zammit et al., 2010; Bourque, Van der Ven & Malla, 2011). Under these conditions, the interenactive constitution of reality may be undermined.

26  In contrast to delusion-like ideas or “ontic delusions” in paranoia (see introduction above), primary or ontological delusions in schizophrenia hardly lend themselves to practical engagement and appropriate action. On the contrary, the majority of patients remain surprisingly passive despite severe suffering and experienced persecution.

Top of page


Bibliographical reference

Thomas Fuchs, “Delusion, reality and intersubjectivity: A phenomenological and enactive analysis”Phenomenology and Mind, 18 | 2020, 120-143.

Electronic reference

Thomas Fuchs, “Delusion, reality and intersubjectivity: A phenomenological and enactive analysis”Phenomenology and Mind [Online], 18 | 2020, Online since 01 May 2022, connection on 30 March 2023. URL:

Top of page

About the author

Thomas Fuchs

University of Heidelberg –

By this author

Top of page



Creative Commons - Attribution 4.0 International - CC BY 4.0

Top of page
Search OpenEdition Search

You will be redirected to OpenEdition Search