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Philosophy, and analytic metaphysics in particular, is usually described as an armchair discipline, and exactly for such an armchair methodology it has been the target of ferocious criticisms. In this paper, I argue that the theoretical right to conduct metaphysics from the armchair can be defended understanding metaphysics as a form of Logic (broadly understood as including applied logics, philosophical logics and, especially, philosophy of logic). So characterized, the typical practice of metaphysics is not more problematic than the armchair methodology routinely employed in the study of Logic.

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1. Metaphysical magic

  • 2 That of the ‘armchair’ is actually a larger category than the a priori. See Williamson (2007) or No (...)

1Philosophy, and analytic metaphysics in particular, is often described as a discipline widely conducted a priori or, as it is sometimes put, from the armchair.2 It is exactly for such an armchair methodology that analytic metaphysics has been the target of ferocious criticisms. If metaphysics aimed merely at describing our naïve conceptual scheme, an a priori methodology could perhaps be defensible, but metaphysics is not always concerned merely with our folk way of categorizing reality. On the contrary, metaphysicians usually want to discover authentic truths about the universe. But how can metaphysicians do that by sitting in a chair? Being able to investigate the deep structure of reality without leaving the armchair seems like magic. Indeed, to escape this conclusion and the subsequent forced submission to natural sciences, philosophers have sometimes looked for a suitable sort of magic that could grant the trick, and rational intuition is often proposed as a possible candidate. The idea is that metaphysicians can avoid to dirt their hands with empirical inquiries because they can gather important data by resorting to intuitions of some sort.

  • 3 See, e.g., Ladyman and Ross (2009).
  • 4 See, e.g., Bealer (1998) or Bengson (2015).
  • 5 See Williamson (2007), Cappelen (2012), Deutsch (2015).

2The nature and the legitimacy of intuition, however, is the source of further and hot debates. Those willing to undermine metaphysics in favour of science criticize (or just try to ridicule)3 such a mysterious reliance on intuition, while defenders of metaphysics offered discrepant strategies: some of them put forward elaborated proposals to legitimate rational intuitions,4 while others claimed that philosophical reliance on intuitions is a mere meta-philosophical mythand the armchair approach can be vindicated in some other way.5 In this paper I intend to offer a characterization of the methodology of analytic metaphysics somehow in the middle. To bring forward my point, in a nutshell, I contend that the armchair methodology of metaphysics can be vindicated by stressing the analogies with logical inquiries: metaphysics should be considered as a form of Logic, broadly understood. At the same time, I put mostly aside the problem of the theoretical legitimacy of Logic and assume it. Thus, if the epistemic foundation of Logic requires a resort to intuition, so does metaphysics. If not, neither does metaphysics. The background assumption is that in the case of Logic a possible resort to intuition, besides not being forced, is much less problematic. Accordingly, metaphysics should be considered as informative and epistemically unproblematic as Logic.

3The paper is structured as follows. In the next section I note that the construction of sound arguments requires two things: an inferential ability and a previous grasp of some alleged truths. I then show that the former is a legitimate form of armchair inquiry also when understood as philosophy of logic, which is the topic of the third part. In the fourth section I pass to consider the problem of true premises, arguing that metaphysicians can obtain them by considering metaphysics as a form of Logic. In the fifth part I show that between metaphysical and logical notions there are enough similarities to justify the proposal, while in the sixth I argue that the strategy should be considered in a prescriptive way. I then conclude the paper summing up the main points.

2. Metaphysics and Logic

  • 6 Assuming, for the sake of debate, that thought experiments are not just arguments.

4Metaphysicians are interested in discovering truths about certain issues. Typically, they do not try to discover them by empirical inquiries, divine revelation or artistic inspiration. Instead, they look for sound arguments or exploit forms of rational inquiry such as thought experiments6. Let me focus on arguments first and postpone the resort to thought experiments and the like to section 4. When metaphysicians elaborate sound arguments, to falsify a certain claim they try to show that it has false consequences, while to verify it they show that it is implied by true premises. This way, the standard practice of metaphysicians keeps together two main ingredients: an inferential ability to construct valid arguments and a previous recollection of certain truths (or falsehoods). These two ingredients reflect the fact that, by definition, a sound argument requires two things: a logically valid argument and true premises. If an armchair methodology is to be defended, I must show that both aspects can be achieved without metaphysicians having to leave their seats. Since the claim that valid inferences are attainable from the armchair is rather unproblematic, the main crux of this paper looms upon the other aspect, namely the recovery of true premises. However, given the crucial role Logic plays in my proposal, it is worth spending some words about it. Let me then analyse such two aspects in turn, starting with valid arguments.

5The resort to Logic in metaphysical arguments takes many forms. To cover all such usages I use the term ‘Logic’ (capital ‘L’), reserving the term ‘logic’ for specific logics. First of all, Logic is applied to give form and to construct specific arguments. It is through careful logical analysis and application of particular rules of inferences or axioms that arguments are obtained. Once an argument is developed, the issue of the validity of the inference can be posed in a fully explicit way, so that we have a second role for Logic in the form of mathematical logic. Specifying the logic is also crucial to determine the exact consequences of a claim, and, more generally, of a metaphysical view. The assessment and comparison of certain inferences and of their underlying logics, however, is not just a matter of simple mathematics. Balancing different logics requires venturing into philosophical considerations, so that we have a third sense in which Logic plays a role in metaphysical argumentation, namely in the form of philosophy of logic. Metaphysicians are interested in establishing which logic is the correct one for the issue at hand and how it should be interpreted. Of course, this classification of the logical aspects of metaphysical practice is a profound simplification and idealization, since we usually have a unique procedure going back and forth through the various levels in an inextricable manner. Accordingly, to produce and discuss valid arguments, contemporary metaphysicians rely on and keep together applications of logics, mathematical logic and philosophy of logic.

6It is clearly not hard to show that such aspects are unproblematic for a defence of an armchair methodology. The application of logic is grounded in our inferential abilities and should be taken to be the product of a skill as a priori as it can be. Analogously, mathematical logic, being part of mathematics, is an instance of the most typical a priori discipline. Indeed, I take these quick observations to report the default view and to be enough for my purposes. The only aspect whose armchair status might seem problematic is that of philosophy of logic, so that I devote the next section to it.

3. Philosophy of logic from the armchair

7Since philosophy of logic pertains to philosophy, one might reasonably suspect that here we meet the same epistemic concern afflicting metaphysics. After all, philosophy of logic is not logic, so that it is not a clearly legitimate a priori discipline. If so, one can ask where philosophers of logic take their evidences and the initial problem seems to emerge already at this point. I believe that in this case, however, several considerations can be put forward to weaken the force of the worry. Indeed, I should start by stressing that no great attack against philosophy of logic has ever be conducted or, at least, no criticism comparable to those put forward against metaphysics seems available. Philosophy of logic is seldom questioned as a legitimate area of study and is usually assumed to be a safe kind of armchair inquiry. Of course that this is the common view does not mean that the orthodox position is correct. Nonetheless, given that we lack positive criticisms, the actual burden of the proof is on opponent’s shoulders and we are justified in adopting the usual position. At the same time, given the importance of philosophy of logic for the proposal of this paper, I briefly argue in favour of the orthodox stance.

8First of all, problems of theoretical legitimacy are usually much less pressing for the philosophies of specific sciences. Such philosophies can perhaps be accused of being useless for the scientific researches conducted in the related fields, but this concern usually does not affect their theoretical legitimacy. Indeed, often scientists themselves venture into the adjacent philosophical area, perhaps inadvertently, to reflect on the nature of their own work. Analogously, it can also be argued that scientists need some amount of philosophical speculation to carry out their research programs, so that banning the possibility of critically investigating them would undermine the very legitimacy of the related science rather than delegitimate the corresponding philosophy. One of the reasons why philosophies of sciences are usually considered less theoretically troublesome has probably something to do with the fact that it is a specific science, whose legitimacy is mostly granted, what provides the topic of the philosophical speculation at stake. Thus, a philosophy of a certain science appears somehow to heir the theoretical legitimacy from the science it relates to. Accordingly, philosophy of logic derives some legitimacy from logic itself. Clearly, if these observations still do not answer the question of what is the source of evidence employed by philosophers of logic, it shows why the question is not much worrying. Here we also find an apparent discrepancy with respect to metaphysics. Given that metaphysics seems to be an autonomous discipline, and not a philosophy of a particular science, it cannot invoke the same kind of derivative legitimization we have for philosophy of logic, philosophy of physics and the like, unless it is reduced to some of them.

  • 7 I put aside minor issues about the possible empirical nature of logic, such as in Putnam (1968).

9Second, the epistemic status of the investigations conducted in philosophies of particular sciences is often tied to the nature of the related science. If a philosopher discusses some aspects of philosophy of mathematics, for instance the idea of potential infinity in set theory, then it seems that her investigation can rightfully be conducted from the armchair. This is because she would mostly appeal to a priori results in set theory or employ the same kind of theoretical resources (possibly including rational mathematical intuitions) appealed to by mathematicians. By contrast, if one studies philosophy of biology, then she would have to appeal to results obtained a posteriori, so that her entire speculation would rely, perhaps remotely, on empirical research. Given that mathematical logic is a paradigmatic case of an a priori discipline, we have that philosophy of logic sits better with the a priori inquiries than with the a posteriori ones.7

  • 8 Williamson (2004).
  • 9 See Nolan (2015).

10Taken together, the two points above give some preliminary reason in favour of the legitimacy of the a priori approach usually employed in philosophy of logic. However, one might still object that in philosophy of logic (and similarly in other special philosophies as well) philosophers typically appeal and discuss logical issues also under the light of considerations which might render philosophy of logic both a posteriori and problematic. Such generic considerations typically have either a linguistic nature or a very general and pre-theoretical character. Examples are considerations about the semantic and inferential behaviour of connectives and quantifiers, pre-theoretical claims about features of the relation of logical consequence or about general principles, such as excluded middle or semantic bivalence. None of these aspects, however, is particularly problematic for our concerns. On the one hand, if a resort to linguistic competence were enough to make a claim a posteriori, then every claim would be rendered a posteriori, making the distinction useless. At the same time, although claims based on semantic competence can be revisable, they can hardly be considered systematically unreliable. Thinking otherwise would push us towards a form of radical skepticism which would undermine our very capacity of judging.8 On the other hand, the general pre-theoretical claims have usually the form of apparent trivial information and commonplaces, so that they should not be considered problematic, unless strong reasons to think otherwise are presented (think of excluded middle or the transitivity of logical consequence). This situation is not even limited to logic, since any scientific enterprise moves from a base of similar pre-theoretical commonplaces. Moreover, although an a posteriori characterization of such commonplaces might be cogent in certain cases, they are not the result of any specific empirical inquiry. They are just considered trivial and shared by most adult human beings. For these reasons, if considering them a priori might be incorrect, an a posteriori characterization could be equally misleading. It is at this point that resorting to the notion of armchair investigation instead of that of a priority is handy. By it we stress the fact that an inquiry, although possibly not strictly a priori, is not the result of a specific active empirical inquiry.9 Keep in mind, however, that we can claim that such an appeal to pre-theoretical principles is theoretically safe also because it pertains to a discipline (Logic) whose legitimacy is unquestioned. These observations, thus, have more an illustration purpose than an apologetic one.

4. Metaphysics as Logic

11Metaphysicians do not only look for valid arguments, they also pursue sound ones. To have soundness, beside validity, however, it is necessary to have also true premises. Here is where other forms of theoretical resources kick in and we have the crux of our problem: how do metaphysicians obtain true premises without engaging in serious empirical investigations? To solve this issue I want to stress even further the analogy between metaphysics and Logic broadly understood. I suggest to align metaphysics with formal sciences, arguing that the logical side of the story does not only provide a good account of the inferential aspect of metaphysics but of metaphysics as such. Metaphysics as a whole is to be understood as the result of the intertwining of applications of logic, mathematical logic and philosophy of logic, just extended to cover other notions beside the usual logical ones. In particular, we should include so called philosophical logics. Accordingly, the effort of arriving at metaphysical theories parallels the effort necessary to devise logics. In other words, to establish and interpret the principles governing, for instance, a necessity operator or a predicate for potentiality, metaphysicians invoke the same kind of considerations logicians use to set out the principles governing quantifiers or to claim that excluded middle holds. In particular, metaphysicians would obtain true premises in the same way logicians (and philosophers of logic in particular) do. If this attempt were successful, the pay off would be clear. According to this interpretation, the armchair methodology of metaphysics would be as unproblematic as the armchair methodology usually employed in Logic, and the initial worry would evaporate or at least be substantially weakened. The two methodologies would collapse, and the defence of armchair metaphysics would coincide with the defence of the epistemic legitimacy of Logic. Since Logic is reliable, the attack against metaphysics would vanish.

12One might object that also other, if not all, philosophical disciplines are engaged in ‘specifying the principles’ of some notion, so that there is a serious risk of over generalization: every branch of philosophy would be Logic. Analogously, the study of the logic of any philosophical notion would count as a kind of metaphysics. To correct the approach, however, it is enough to add a few remarks. First, there are many branches of contemporary philosophy that cannot be conducted exclusively from the armchair (philosophies of particular natural sciences, philosophy of mind etc.), so that not every philosophical study would amount to Logic. Secondly, we can specify in advance what notions count as metaphysical notions, so that only in certain cases the corresponding Logic would result in a metaphysical inquiry. To do that, we do not need a previous substantive grasp of metaphysics but only of its subject of investigation. In particular, we should note that metaphysics look for objective principles, namely principles that are correct from a third person point of view, so that investigations intended to capture a cognitive perspective are ruled out. Finally, while I just want to propose an interpretation of analytic metaphysics, I am well open to consider all armchair philosophy as a kind of Logic.

5. Analogies between Logic and metaphysics

13To complete this strategy, I must now argue that metaphysical and logical notions are similar enough to be considered of the same sort and to be treated in the same way. Such a strategy presupposes that we have a good account of what logical notions are and of their epistemology, so that we can extend it somehow to metaphysics. Both aspects, however, are subject to hot debates to which I cannot do justice here. I do not need to enter such disputes, however, since a weaker and easier strategy should be enough for my purposes. Instead of explaining what logical notions are and then show that metaphysical notions satisfy the same or a similar account, I just point to several analogies between metaphysics and Logic making the idea that they are analogous appealing. Although this cannot establish my thesis in a definitive way, it still renders the logical understanding of metaphysics an option worth exploring.

14First of all, metaphysical investigations often start from apparent inconsistencies or paradoxes that involve nothing but trivial assumptions and logical inferences. Think of the puzzle of the ship of Theseus or the Sorites paradox. Solving a paradox, however, is eminently a logical task. It requires a specification of the principles involved in the argument and a possible rejection or revision of some of them. We have then a first analogy: both metaphysics and Logic thrive on paradoxes.

15Another simple fact that pushes metaphysics towards the formal sciences instead of the natural ones is that metaphysicians are often interested in abstract entities, which can hardly be investigated by elaborating experiments to test a theory or to extract information directly. This clearly is not to say that empirical findings and datas cannot be metaphysically relevant, but it shows that the role of experience must be of a different sort from the one played in natural science. If abstract entities help see metaphysics at least as a formal science, other features exhibit a stricter similarity with Logic itself.

  • 10 See Morganti and Tahko (2017).
  • 11 I put questions of logical pluralism aside for the sake of simplicity.

16One of these similarities is generality. The categories metaphysics employs cover an extremely variegate kind of entities. We can, i.e., speak of the properties of cats but also of the properties of sets, of molecules, of sunsets, of laws, and so on. Given such a generality, it comes as no surprise that specific empirical findings are often useless and mere simplifications of scientific results are enough.10 The same kind of generality and the ensuing limited relevance of new empirical findings can be found also in Logic. For instance, we are supposed to exploit a conjunctive connective in arguments about cats, sets, molecules, sunsets, laws, and so on. Accordingly, it might be suggested that we are supposed to apply the same metaphysical notions (such as modality, property or parthood) in every area in the same way we are supposed to apply the same notion of conjunction.11

17The pervasive indifference to experience connected to generality is a trait common to both metaphysics and Logic that is worth emphasizing on its own. Rival metaphysical views are typically compatible with all empirical information that could be gathered even in highly idealized conditions. What source of experiment could we arrange to settle the puzzle of the ship of Theseus or the problem of universals? It is straightforward to see the analogies with Logic, since also Logic exhibits a similar kind of radical empirical indeterminacy. For instance, how can we empirically decide whether excluded middle is a logical law or whether logical consequence is transitive? For both metaphysics and Logic, experience and natural science seems relevant, at most, at a very general level and only exceptionally – and highly controversially – in particular cases.

  • 12 See Russell (1940).

18A fourth analogy derives from the strict relation with language. The nature of some significant metaphysical notions is so strictly entrenched with language that it is a reasonable view that of considering them as the manifestation of an entirely linguistic and not of a worldly phenomenon. A shining example is that of modality. Although the old orthodox position locating it in language instead of things is no longer dominant, it is not absurd. Analogously, one can reasonably wonder whether logical laws reflect universal principles grounded in reality or just embody the particular behaviour of certain linguistic expressions. The strict analogy between metaphysics and Logic strikes again.12

19The possible linguistic source of metaphysical phenomena leads to a further interesting feature. Metaphysicians often consider notions whose treatment has a prominent inferential aspect. What I mean is that to enlighten a metaphysical notion, an important part of the work is often that of specifying the principles that govern it or connecting it with other notions. In the best (and seldom realized) case this results in a definition, but in the most frequent scenario we just have general principles networking the notion under study with other concepts. A clear example is provided by mereology. A standard presentation of mereology starts with an illustration of core principles that are assumed to capture a core set of axioms characterizing the notion of parthood. Mereologists then proceed to discuss what other principles should be added to this minimal theory of parthood. Clearly, this approach is nothing but a process of yielding a logical or a formal theory.

20Sixth, both metaphysicians and logicians are both eminently interested in establishing the consequences of certain claims or what follows from what. Logicians make the very relation of logical entailment one of the key topic of their study. Analogously, metaphysicians are often interested in figuring out what is entailed by a certain view. For instance, they want to know what are the consequences of nominalism or whether it is compatible with modal realism. The emphasis on conditional claims and on the logical consequences of certain premises prompts another analogy between metaphysics and Logic.

21Finally, the apparent harmless nature of the pre-theoretical considerations exploited by logicians seems to be exhibited also by those used by metaphysicians. Exactly as it seems preposterous to question the principle of excluded middle or the transitivity of the relation of logical consequence before having developed serious arguments, it would be absurd to question the legitimacy of many metaphysical background assumptions without specific reasons. For instance, a traditional source of metaphysical speculation is provided by arguments such as: ‘the statue on my desk was made this morning; the lump of clay on my desk has existed for a long time; so the statue on my desk is distinct from the lump of clay on my desk; so distinct material objects sometimes spatially coincide’. This is a case where no explicit justification of the (possible) truth of the premises is put forward because it would be completely trivial. Even under this respect the practice of metaphysicians seems to parallel that of logicians.

6. Stating the view

22Given the above analogies, I think that considering metaphysics a form of Logic is far from being a peregrine view. However, a couple of remarks to comment the above considerations are important. First of all, I do not consider the mentioned features exhaustive. Indeed, I believe that other similarities between Logic and metaphysics can be found. Secondly, I am not claiming that the similarities are always perfect. For instance, one can reasonably argue that if inferential principles and axioms could be enough to fix the meaning of logical expressions, some metaphysical notions are different. The axioms of minimal mereology, e.g., are not enough to distinguish a notion of parthood from a generic partial order. Beside the inferential part, we need to ground the expression somehow referentially. Still, I think that a case can be made that also in such cases the analogies are stronger with formal sciences than with natural sciences. Take for instance natural numbers. A first order formalization of arithmetic (such as Peano Arithmetic) is not able to pick out the standard model, so that we have a lot of possible interpretations compatible with those axioms. However, empirical methods do not seem apt to shed light on natural numbers and mathematicians just keep looking for axioms and relying on armchair investigations. Analogously, even if some referential practice is needed to fix the meaning of metaphysical notions such as ‘parthood’, its reference can hardly provide a direct object of research. We cannot discover the nature of parthood by analysing parts in the same way we do, for instance, with specific natural kinds such as water. Thirdly, I do not want to contend that the above similarities hold in the same way in every branch of metaphysics, but I still think that the analogies, imperfect and partial as they may be, put us on the right track for several reasons. After all, the hypothesis could be useful to make sense at least of certain aspects of metaphysical inquiries without having to vindicate it in its totality. Even if the proposal succeeded in making sense only of a limited kind of approach, we would have at least secured some amount of metaphysical speculation. Alternatively, a more radical viewed could be tempted. We could say that those investigations requiring more than a logical approach should not be considered as entirely metaphysical. Perhaps in certain areas we use the label ‘metaphysics’ where what we actually have is a mixture of metaphysics (as Logic), philosophy of a particular natural science and that very particular natural science (think, for instance, of the metaphysics of time). Finally, let me stress that even if metaphysics did not perfectly match Logic, we could still take the logical interpretation as a working hypothesis to be evaluated for its theoretical virtues. The above analogies then should be taken more as motivations than as conclusive claims. This approach would lead to a prescriptive version of the proposal. In other words, if the identification of metaphysics and Logic proved fruitful, we could read it in a prescriptive sense according to the maxim: identify metaphysical inquiries on X with the inquiries that can be identified with the study of the Logic of X (in a broad sense)! In this way, purely metaphysical approaches could perhaps have their domain limited, but their theoretical legitimacy would be retained. Stressing this prescriptive approach, we could read the maxim not just as dictating an interpretative view, but also an operative one: Do the metaphysics of X as you were studying the Logic of X! My idea is that the resulting discipline would still significantly overlap with traditional metaphysics, so that the prescription would not be completely revisionary.

  • 13 For example the logic devised in Vetter (2015).

23For the sake of clarity, let me rephrase the above proposal in different words. The analogies give enough ground to put forward the idea that metaphysics could be understood as a mere form of Logic. Indeed, given that the aspects related to the applications of logic and to the pure mathematical study of a theory are not eminently philosophical, one had better focus on the philosophical side of the story. Metaphysics would mostly be viewed as the philosophy of certain philosophical logics. Accordingly, we should see the metaphysics of parthood as the philosophy of formal mereology, the metaphysics of modality as the philosophy of modal logic, the metaphysics of fundamentality as the philosophy of the logic of grounding, the metaphysics of time as the philosophy of temporal logic, the metaphysics of dispositions as the philosophy of the logic of powers,13 and so on and so forth. To be precise, the idea is better stated as claiming that metaphysics can be regarded as a part of philosophy of logic, since the latter could include topics usually considered with little or no metaphysical interest.

  • 14 I am sympathetic with the idea that there are two main conceptions of metaphysics that should be ta (...)
  • 15 Ladyman (2012), e.g., while crudely criticizing classical analytic metaphysics makes an exception f (...)

24Are there significant aspects of metaphysical inquiry that escape such a conception of metaphysics as Logic? I do not think that the answer is easy, and, personally, I tend to give a negative answer. But that is not the point. If nothing is left out by this view then the better for my proposal. If something is left out, then we can either reject it as an illegitimate form of metaphysics or propose a different account integrating the view.14 I do not intend here to exclude the latter strategy, since I just want to stress the perks of accepting a possibly partial understanding of metaphysics as the philosophy of philosophical logic, or, more generally, as Logic. This solution would provide a satisfying, and basically easy reply to the epistemic challenge to metaphysics that would preserve its theoretical autonomy. Moreover, it would apparently be able to vindicate a significant amount of the actual practice of contemporary analytic metaphysicians. Of course, we still have to provide a more throughout account of the epistemology of Logic, enlightening its nature and defending the legitimacy of its armchair methodology. However, this is a different and possibly easier task. If the critics of metaphysics are not seriously worried by the theoretical legitimacy of Logic, they should not be worried by metaphysics as well.15

  • 16 For instance, Linsky (1971), Williamson (2013).
  • 17 For instance, Prior (1955), Mellor (1986).
  • 18 For instance, Fine (2012), Paganini (2017).
  • 19 For instance, Cotnoir (2013), Turner (2014).
  • 20 See Schnieder (2011), Fine (2012).
  • 21 Such as Torza (2015).
  • 22 Plantinga (1974).
  • 23 Given the importance of Lewis’ On the plurality of Worlds (1986) let me briefly comment on it. On t (...)

25I conclude this section by pointing first to some samples of metaphysical work that fit the proposed picture, and then by discussing a typical example that seems to provide an hard case for my approach. On the positive side, a good amount of metaphysical works on modality, or on the relation between modal logic and essentialism16 are easily regarded examples of my view. Temporal logic offers similar instances,17 and many works on vagueness18 and mereology19 fit the story, as recent works on grounding as well.20 Indeed, I should stress the clear analogies between this kind of studies and typical researchers in contemporary philosophy of logic.21 The rise of formal methods and the similarities with researches in philosophy of logic should not even strike the reader as unexpected news. My approach just takes this trend seriously and gestures towards a complete amalgamation of the two ingredients. As a seemingly recalcitrant case consider instead a classic book such as Plantinga’s The nature of Necessity.22 Plantinga’s discussion is conducted without reference to any specific logic and it is not even clear if it could be articulated in terms of a logical framework.23 Thus, an important piece of contemporary metaphysics seems to escape my proposal. To relent the worry raised by this and many other similar metaphysical works, I can invoke one of the main historical roles performed by philosophy, namely its contribution to the creation of specific sciences. By promoting theoretical reflections on particular topics, philosophical investigations can, and often do, precede the born of a corresponding science. This is important because it enlightens a crucial aspect: to some extent, philosophy of logic and of particular logics as well, can also be conducted independently from the details of a formal system. This can be the case, for instance, when general notions or basic foundational issues are discussed. If we can legitimately speak of philosophy of logic insofar as a certain debate focuses on logical notions, then the proposal is not immediately undermined or limited by the existence of important works in metaphysics that cannot be related to a specific logical framework. Thus, to overcome the objection it is enough to show that metaphysical notions are better understood as logical notions. A claim I already argued for.

7. Conclusion

26Metaphysics is frequently attacked for its armchair methodology. In a sense, the initial worry was motivated by the temptation to align metaphysics with natural science. A temptation that, according to my view, should be resisted. In this paper, I have argued that the theoretical right to conduct metaphysics from the armchair can be defended by understanding it as a form of Logic. Given that, in the case of Logic, an armchair approach is considered viable, the same would straightforwardly hold for metaphysics too. Thus, although I have left the problem of the epistemology of Logic open, the proposed identification represents an important progress. Indeed, metaphysicians should stop worrying that there might be something especially problematic about their enterprise, let alone burn their armchairs.

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Bealer, G., 1998, Intuition and the Autonomy of Philosophy, in Rethinking Intuition: The Psychology of Intuition and Its Role in Philosophical Inquiry, Lehnam (MD), Rowman & Littlefield: 201-240.

Bengson, J., 2015, The intellectual given, “Mind”, 124 (495): 707-760.

Cappelen, H., 2012, Philosophy Without Intuitions, Oxford, Oxford University Press.

Cotnoir, A., 2013, Composition as general identity, in K. Bennett, D.W. Zimmerman (eds), Oxford Studies in Metaphysics, Oxford, Oxford University Press: 294-322.

Deutsch, M., 2015, The Myth of the Intuitive: Experimental Philosophy and Philosophical Method, Cambridge (MA), The MIT Press.

Fine, K., 2012, Guide to Ground, in F. Correia, B. Schnieder (eds), Metaphysical Grounding, Cambridge, Cambridge University Press: 37-80.

Ladyman, D., 2012, Science, metaphysics and method, “Philosophical Studies”, 160 (1): 31-51.

Ladyman, J., Ross, D., 2009, Every Thing Must Go: Metaphysics Naturalized, Oxford, Oxford University Press.

Lewis, D.K., 1986, On the Plurality of Worlds, Oxford, Wiley-Blackwell.

Linsky, L. (ed.), 1971, Reference and Modality, London, Oxford University Press.

Mellor, D.H., 1986, Tense’s tenseless truth conditions, “Analysis”, 46, 4: 167.

Mellor, D.H., 2017, Moderately naturalistic metaphysics, “Synthese”, 194, 7: 2557-2580.

Morganti, M., Tahko, T.Nolan, D., 2015, The a posteriori armchair, “Australasian Journal of Philosophy”, 93, 2: 211-231.

Paganini, E., 2017, Vague objects within classical logic and standard mereology, and without indeterminate identity, “Journal of Philosophical Logic”, 46, 4: 457-465.

Plantinga, A., 1974, The Nature of Necessity, Oxford, Clarendon Press.

Prior, A.N., 1955, Time and Modality, Westport, Greenwood Press.

Putnam, H., 1968, Is Logic Empirical?, “Boston Studies in the Philosophy of Science”, 5.

Russell, B., 1940, The Philosophy of Logical Atomism, La Salle, Open Court.

Schnieder, B., 2011, A logic for ‘because’, “Review of Symbolic Logic”, 4, 3: 445-465.

Torza, A. (ed.), 2015, Quantifiers, Quantifiers, and Quantifiers. Themes in Logic, Metaphysics, and Language, Heidelberg, Springer, Synthese Library, vol. 373.

Turner, J., 2014, Donald Baxter’s composition as identity, in D. Baxter, A. Cotnoir (eds), Composition as Identity, Oxford, Oxford University Press.

Vetter, B., 2015, Potentiality: From Dispositions to Modality, Oxford, Oxford University Press.

Williamson, T.2004, Philosophical ‘intuitions’ and scepticism about judgement, “Dialectica”, 58, 1: 109-153.

Williamson, T.2007, The Philosophy of Philosophy, Oxford, Wiley-Blackwell.

Williamson, T.2013, Modal Logic as Metaphysics, Oxford, Oxford University Press.

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2 That of the ‘armchair’ is actually a larger category than the a priori. See Williamson (2007) or Nolan (2015).

3 See, e.g., Ladyman and Ross (2009).

4 See, e.g., Bealer (1998) or Bengson (2015).

5 See Williamson (2007), Cappelen (2012), Deutsch (2015).

6 Assuming, for the sake of debate, that thought experiments are not just arguments.

7 I put aside minor issues about the possible empirical nature of logic, such as in Putnam (1968).

8 Williamson (2004).

9 See Nolan (2015).

10 See Morganti and Tahko (2017).

11 I put questions of logical pluralism aside for the sake of simplicity.

12 See Russell (1940).

13 For example the logic devised in Vetter (2015).

14 I am sympathetic with the idea that there are two main conceptions of metaphysics that should be taken apart: metaphysics as philosophy of (philosophical) logic and naturalized metaphysics (to be interpreted as philosophy of natural sciences).

15 Ladyman (2012), e.g., while crudely criticizing classical analytic metaphysics makes an exception for those researches connected with philosophical logic.

16 For instance, Linsky (1971), Williamson (2013).

17 For instance, Prior (1955), Mellor (1986).

18 For instance, Fine (2012), Paganini (2017).

19 For instance, Cotnoir (2013), Turner (2014).

20 See Schnieder (2011), Fine (2012).

21 Such as Torza (2015).

22 Plantinga (1974).

23 Given the importance of Lewis’ On the plurality of Worlds (1986) let me briefly comment on it. On the one hand the considerations offered for Plantinga’s book can be straightforwardly extended to cover also Lewis’. On the other hand, it is much less clear that Lewis’ discussion does not (at least also) pertain to philosophy of modal logic, as witnessed e.g., by his discussion in section 1.2.

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Andrea Strollo, « Metaphysics as Logic », Rivista di estetica, 69 | 2018, 7-20.

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Andrea Strollo, « Metaphysics as Logic », Rivista di estetica [Online], 69 | 2018, online dal 01 mars 2019, consultato il 30 octobre 2020. URL : ; DOI :

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Andrea Strollo

Department of Philosophy, Nanjing University, Nanjing (China), andrea_strollo[at]

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