1Philosophy of economics (defined as a subdiscipline of philosophy of science concerned with economics) seems to have recently turned from studying models and explanations to causal inference and the use of causal evidence for economic policymaking. This turn in the research interests of philosophers studying economics is visible in the works of, e.g., Alessio Moneta and Federica Russo (2014), Julian Reiss (2014; 2015), François Claveau and Luis Mireles-Flores (2014; 2016), Mireles-Flores (2016), Tobias Henschen (2018a; 2018b; 2020), Mariusz Maziarz and Robert Mróz (2020a; 2020b), and also mine book-length contribution (Maziarz 2020). Ricardo Crespo’s (2020) book The Nature and Method of Economic Sciences. Evidence, Causality, and Ends develops and extends this strain of literature. It is an excellent read that succeeds in bridging together in-depth discussions of both history of economic thought (including history of economic methodology) and contemporary philosophy of science. In my opinion, this alone suffices to recommend the book. Most current works, probably due to the growing specialization among economists, historians, and philosophers, either focus on historical debates or engage in recent discussions. Such broad and history-informed approaches are scarce nowadays.

2Crespo manages to present economics as a multidimensional, pluralistic science (or even sciences). This also distinguishes the book from existing literature that usually focuses on a handful of related research methods or on a school of economic thought. The Nature and Method of Economic Sciences. Evidence, Causality, and Ends can be considered as a stand-alone introduction to or a study of philosophy of economics. The book addresses the questions of what the economy and economics are and what approaches to research used by economists are. It also discusses the role of values in economics and the methodology of economic policymaking. While the broadness of the topics considered in the book is, in my opinion, its most significant advantage, it can also be regarded as a drawback. The reason is that each of the chapters covers a topic that is broad enough to justify a book-length treatment. Due to the broadness of the topics, the author strives to be concise and shortens his thoughts to a great extent, which may impede the reception of the arguments presented throughout the text by an unsophisticated reader.

3Furthermore, some chapters are vaguely related to the rest of the book. For example, the analysis of the methodology of policymaking (as opposed to the methodology of economics as an academic discipline) in chapter 10 is, in my view, the most exciting part of the book that shows that philosophy of economics is not only an academic discipline practiced as an intellectual entertainment, but it is highly relevant for both economics and economic policymaking. It deserves longer and more in-depth treatment. However, the question of how to succeed in economic policymaking is not, in my view, related to policymaker’s goals, as discussed in chapter 9. One could argue that the exact same skills and expertise are needed for successful policymaking to achieve common good as for policymaking aimed at common bad, whatever that would be. In what follows, I discuss each chapter's content in some detail and take issue with some of Crespo’s arguments.

4The introduction defines the book scope as being a proposal for economics to include different perspectives (2). In particular, Crespo distinguishes among the following five levels of economics: “statistical and historical descriptive level” (which describes and measures current situation and economic history), “a causal efficient explanatory level” (which seeks to deliver causal explanations), “a teleological explicative or understanding/interpretative level” (which explains economic behavior referring to agents’ goals), “a normative level” (which analyzes and sets goals for economic agents), and what used to be labeled the “art of Political Economy” (methodology of policymaking) (4). In contrast to the standard view on economics, Crespo defines the discipline by reference to the subject of research, as disciplines that study economic phenomena. The plural form of ‘disciplines’ is not accidental because Crespo finds economics an umbrella term, consisting of five fields. Crespo admits that his position is inspired by Sandra Mitchell’s (2009) integrative pluralism. As the author delineates throughout the book, these different economic sciences deal with the same material object (the economy) and study it from different perspectives.

5Chapter 2 addresses the question of what is the subject of economics, i.e., what ‘the economic’ refers to. Crespo reminds us of Uskali Mäki’s view that one of the most challenging problems of philosophy of economics is the question of what ‘the economy’ is (i.e., what is the nature/essence of economics). To address it, Crespo draws on Neville Keynes, Carl Menger, and Herbert Simon. For instance, Menger differentiated actions related to acquisition, possession, and the use of goods from doing so efficiently. In the broad sense, the discipline deals with ‘the economic’, while, in the narrow sense, it studies conditions for optimal and efficient (economic) decisions. Based on a wide historical analysis of the views of economists and philosophers, Crespo distinguishes among three meanings of the term ‘economy’.

6Chapter 3 focuses on defining the discipline concerned with studying the economy. The chronological review of economists’ views on their discipline shows that the definitions and economics itself evolve in time. Economics used to be considered a broad field, but it is now interpreted more narrowly as connected to the instrumental utility maximization. This chapter (and especially pp. 43-46) is an excellent example of Crespo’s knowledgeability in the history of economic thought. For instance, the analysis of Carl Menger’s views on economics is so elaborated and conducted with care for details that Crespo explains the meaning of Verstehen taking into account the use of this term in the German philosophical tradition that is, according to the author, related to understanding in human sciences, describing human goals. The only problem I can see is that such analyses, despite being impressive and enlightening for history of economic thought and history of philosophy of economics, are possibly irrelevant for the current debates. The reason is that, since the late nineteenth century, both economics and the economy has changed enormously. The evolution of economists' research methods in the second half of the twentieth century is exceptional (see Hamermesh, 2013) and statistics and econometric modeling were developed no earlier than in the 1920s and 1930s. The economy has changed too, with globalization and digital economics being the prime examples. In my opinion, these changes pose the question of whether the views of economists voiced over a century ago can still be considered relevant for the contemporary debates.

7Chapter 4 focuses on the empirical side of economics and discusses how the economy is measured. I appreciate Crespo’s discussion of the role of values and methodological decisions in the production of economic data. A great example is the discussion of how the Human Development Index (HDI) was developed. This topic is fascinating, but also it has significant consequences for the role of econometric models and the philosophy of economics in general. Unfortunately inconsistent conclusions can emerge due to different but plausible methodological commitments of econometricians and this problem has hitherto received insufficient attention (see Moosa, 2019). I believe that this part of Crespo’s book can point the attention of methodologists to this topic and, in effect, help in improving the quality of evidence from econometric models. However, Crespo could have also discussed experimental methods to a greater extent since they can also be considered sources of economic data.

8Chapter 5 is the first of the three chapters focusing on economic theory. Therein, Crespo puts forward his argument that economists employ the Aristotelian view on causality. He opposes the reductionist reading of Hume’s ideas. Humean reductionism states that humans cannot observe causes and can only discover constant conjunctions of events and, adding time precedence, make inferences regarding causality. However, this view can be considered as an epistemic notion used to differentiate causal and non-causal relations. At the same time, Hume was a causal realist (see the new-Hume debate, e.g., Hardt, 2017). Crespo leans toward the capacities view on causality. The capacity approach identifies causality with indeterministic tendencies that produce effects. Crespo supports the argument with the discussion of Mill and Cartwright.

9Chapter 6 focuses on what Rodrik (2015) labels the logic of efficiency and what Crespo denotes as “positive economics, the science that studies economic phenomena from a restricted economic point of view, that is … a method of applying maximizing instrumental logic to economic phenomena” (109). Crespo views positive economics as having limited power to explain or predict and argues that models are context-dependent because of the omitted (noneconomic) factors that are excluded from models. The author exemplifies the argument with the comparison of inflationary expectations in Argentina to countries with stable economies. According to Crespo, the factors that are usually excluded from economic modeling make the difference between the two inflationary regimes.

10Furthermore, being a causal monist, Crespo opposes Reiss’ (2015) pluralistic view that econometricians, statisticians, and experimental economists accept different notions of causality. Crespo interprets these different types of evidence as supporting conclusions regarding a single concept of causality. Based on causal realism, Crespo endorses the view that good economic models accurately represent causes. While this normative guidance seems to be a widespread view among both economists and philosophers of economics, the author substantiates it philosophically with the views of John Poinsot (John of St. Thomas), an early seventeenth-century Portuguese Thomist theologian. Taking into account that there are many realist positions regarding causality in economics or science in general, the book, in my opinion, is missing an in-depth explanation for why this and not some other philosophical stance is employed. Still, Crespo does a great job of discussing lesser-known perspectives in philosophy of causality that may engage both philosophers and economists.

11Chapter 7 is an exciting attempt at reviving Aristotelian final causes that have been excluded from the domain of science for many centuries. According to Crespo, economic theory (interpreted in previous chapters as describing causes of the economic phenomena) should move beyond purely economic explanations. In this chapter, economists are advised to include the processes of choosing ends given existing means. These ends, in the Aristotelian framework, are final causes (135). Crespo claims that those economists that exclude the analysis of ends of economic behavior do not study real situations but model abstract cases. While I agree that some axiomatic, theoretical models can only be interpreted as representing a possible mechanism and the question regarding its actuality remains open (see Maziarz, 2020, 125-126), I do not think that including the purported goals of economic agents into economic models is going to change the situation. In my opinion, causal claims established with theoretical models, econometric analysis, or still other methods can be used for different goals. For example, regardless of whether a policymaker wants to reduce inflation or raise it, knowing a causal relation between monetary base and inflation (if true) is helpful. Still, I need to note that Crespo’s support for final causes in economics is very thought-provoking.

12Chapter 8 takes issue with the value-free thesis and supports the role of ethical values in economics. Crespo distinguishes between ethical normativity and technical normativity and argues that economics is concerned with the latter. The author observes that the distinction between facts and values stems from Hume’s division on matters of fact and relations between ideas (‘oughts’ and ‘ises’ in Hilary Putnam’s words). I enjoyed Crespo’s reconstruction of the debate on the influence and role of values in economics very much. The author reconstructs this debate by distinguishing the following three types of arguments. First, some scholars deny the fact-value distinction and argue that the two are entangled in scientific practice. Second, sociologists studying social processes observe that values unavoidably shape research results. Finally, the author reminds us of his own (Crespo, 2019) argument for including non-epistemic values in the human sciences. According to Crespo, the question of the role values play in ‘economic reasoning’ remains unanswered. From my perspective, the discussion of how nonepistemic values enter positive economics is incredibly engaging. The author exemplifies this with a detailed discussion of the construction of Human Development Index and required choices determined by researchers’ values.

13Chapter 9 argues that the role of normative economics is to determine how economics can improve the ‘common good’ of people. The author discusses Aristotle’s view on common good as eudaimonia for everyone, which is only achievable in the polis and proceeds with the discussion of common good in the twentieth-century philosophy, particularly the views of John Rawls and liberalism. Crespo also discusses the Aristotelian view on human nature and its implication for what ‘common good’ is. Inspired by Aristotelian virtue ethics, Crespo uses the notion of ‘common good’, a term different from the now-popular ‘well-being’ because he believes the term used by Aristotle is more relevant for the goals of economic policymaking. Crespo considers the economics of happiness and concludes that it should employ the Aristotelian notion of eudaimonia. His argument is based on the analysis of Sen’s capability approach and liberal paternalism. He concludes that normative economics should focus on the common good and, according to Crespo, will benefit from incorporating Aristotelian ethics.

14Chapter 10 focuses on the art of economics or, to put it differently, the methodology of economic policymaking, i.e., the question of how to achieve ends. Crespo revisits Mill’s view that the art of policy-related decisions focuses on and analyzes what is humanly attainable and asks, citing Colander (1994, 36) if the methodology of the art of economic policymaking is different from the methodology of positive economics. Crespo thinks that the methodology of economic policymaking differs from positive economics. He discusses Mill’s and Neville Keynes’s view that those who apply science directly to action are doomed to failure and agrees with Duflo’s opinion that economic policymaking is based on educated guesses instead of being a direct application of science.

15Chapter 10 seems to lack a more in-depth analysis of the conditions and circumstances that influence the success of interventions. Crespo exemplifies the discussion with his and his colleagues’ experience as managers of an investment fund and points out that their success has depended on several skills (mathematical, economic, the ability to predict people’s response to news, and extensive empirical knowledge). However, another plausible explanation for the success of fund managers exists. Namely, even long runs of successful decisions can be ascribed to chance alone if we observe survivors only. Economic policymaking in the strict sense (understood as monetary or fiscal policy, or institutional reforms) can be analyzed differently, refraining from accepting that economic policymakers have skills sufficient for successful interventions. Similarly to Jacob Stegenga’s (2018) argument against the efficacy of medical interventions based on the fact that many diseases improve over time, one could admit that economies survive and develop despite (and not thanks to) policymaking. This view could be supported with the following observations from economic history. First, at least in some cases, economies had developed (despite many crises) when the laissez-faire regime was obeyed by policymakers. Second, macroeconomics has changed substantially during its relatively short history that includes several reversals in policy recommendations. However, we have observed that, at the same time, economies of most countries have continuously developed what may indicate that macroeconomic policy is irrelevant. I believe that Crespo could be sympathetic to my pessimistic or even nihilist take on economic policymaking considering his opinion that policymaking, which denotes managing the whole economy and not just an investment fund, is even more challenging (196).

16Chapter 11 summarizes the main findings from previous chapters. The book gives the impression that it has been motivated by the misfortunate economic history of Argentina. Still, Crespo was able to deliver a monograph that is very engaging not only for policymakers around the globe, but also for philosophers and academic economists, including PhD students. I believe that the most significant contribution of the book is the analysis of economics as a field including different sciences that study economy from different angles. This disciplinary pluralism could be used as a good argument supporting causal pluralism as the notion of causality adequate to economics but the monograph leaves this topic for future studies.