Friedrich A. Hayek’s writings on theoretical psychology, especially 1952’s The Sensory Order: An Inquiry into the Foundations of Theoretical Psychology (TSO), are key to understanding his contributions to several other fields. As Viktor Vanberg shows in an excellent editorial introduction, a significant contribution to the secondary literature in itself, Hayek’s postwar methodological work on the explanatory limitations of the sciences of complex phenomena (a class encompassing, inter alia, economics and the social sciences) and the closely related development of the implications of his theory of spontaneous orders cannot be properly understood without the context provided by his writings on theoretical psychology. Their publication as volume 14 of Hayek’s Collected Works is welcome.

Indeed, a case can be made that there is virtually no part of Hayek’s extensive canon that is not to some extent dependent on his theoretical psychology. (Full disclosure: I have in fact made much of this case in print; see Scheall Reference Scheall2015a, Reference Scheall2015b, Reference Scheall2016). This might be said for many reasons, but none other is needed than the fact that these writings contain the bulk of Hayek’s epistemology, and Hayek was, after all, in Walter Weimer’s words (1982, p. 263; quoted in Vanberg’s introduction, p. 26n105), “at all times an epistemologist, especially when doing technical economics, and even in his historical and popular writings.”

In this regard, it is important to keep in mind that Hayek’s interest in psychology emerged more or less contemporaneously with his interest in theoretical economics. His earliest writing to realize anything like academic standards (that survives) is not a contribution to economics, but an essay that sketches a physiological–psychological theory of the development of consciousness. This essay, published here in English for the first time, was written by a near total autodidact about psychology, albeit with some encouragement from Adolf Stöhr, the then-dying occupant of the same chair of philosophy of inductive sciences at the University of Vienna previously held by Ernst Mach and Ludwig Boltzmann, and to be taken over upon Stöhr’s death by Moritz Schlick. Hayek’s physiological account of consciousness and its naturalistic epistemological implications are very much in keeping with the Mach–Boltzmann–Stöhr–(early, pre-Wittgensteinian) Schlick line of intellectual descent. It is worth recalling also that, before Ludwig Wittgenstein came to monopolize his philosophical attention, one of Schlick’s intellectual lodestars was Hermann von Helmholtz, who also inspired Hayek. More to the point, despite the twenty-five-plus years that separate their writing, the naturalistic epistemological implications of the early essay are in substance identical with those of TSO.

Thus, it seems that Hayek came to the Austrian School of economics and his first dealings with Ludwig von Mises in the early 1920s with a conception, well-formed at least in its basics, of how organisms acquire knowledge of, and from, their environment. Moreover, this theory of knowledge, elaborated more professionally and in greater depth in TSO, remained fundamentally the same in the later book. The mere fact of the early sketch of consciousness of (circa) 1920 and its relation to the more fully developed theoretical psychology of 1952 puts paid to the thesis, which survives in the secondary literature despite only ever being clumsily made (Hutchison Reference Hutchison1981; Friedman Reference Friedman2013), that Hayek experienced some drastic mid-career epistemological or methodological change of heart (or of mind). These facts should similarly finish off the claim, again unfortunately long-lived in the literature despite also only ever being clumsily made (Hutchison Reference Hutchison1981; Boettke Reference Boettke2015; Zanotti and Cachanosky Reference Zanotti and Cachanosky2015; cf. Scheall Reference Scheall2017), that there is some affinity between Hayek’s modern empiricist epistemology and von Mises’s pre-modern “almost eighteenth-century rationalism” (Hayek 1978, p. 137; see Scheall Reference Scheall2015a, Reference Scheall2017). The collection of all of Hayek’s writings on theoretical psychology in one place and, especially, the publication of his very first academic writing on this (really, any) topic, previously available only in German and then only since 2006, marks a significant moment in Hayek scholarship.

One might complain that the present volume does not, in fact, collect all of Hayek’s writings on theoretical psychology in one place. In particular, 1969’s “The Primacy of the Abstract,” his last substantive contribution to the field and a clarification of some of his earlier psychological ideas, is, unfortunately, missing. This is ultimately a minor complaint. “Primacy” appears elsewhere in the Collected Works, in volume 15. One might quibble with the choice to place this piece in the latter volume, alongside Hayek’s essays on The Market and Other Orders, rather than where it might more naturally belong, in the present volume next to his other writings on theoretical psychology. In any case, the reader interested in a comprehensive view of Hayek’s contributions to the field is forewarned that a second visit to the library (or, ideally, bookseller!) will be necessary.

Vanberg’s introduction does a wonderful job of clarifying Hayek’s sketch of a causal explanation of willful action and in elucidating the relationship between Hayek’s work on the “knowledge problem” in two contexts: that of the individual organism and that of societies of such organisms. Vanberg also helps to illuminate the relationship between Hayek’s evolutionary epistemology and the similar work of his friends Karl Popper and Konrad Lorenz. Indeed, Vanberg’s essay is a contribution to our understanding of Hayek’s place in mid-twentieth-century thought, within economics and social sciences, and without.

This being said, I have two criticisms of Vanberg’s introduction, one formal and the other substantive, that detract from my praise of what is otherwise an exceptional editorial performance. I hesitate to even offer the formal criticism, as it is an undoubtedly fussy complaint for me to make. However, it is ultimately so distracting as to push Vanberg’s introduction to the limits of readability. The introduction is easily twice the length that it needs to be to establish Vanberg’s substantive theses. This would be immaterial were it not for the fact that the superfluous length is taken up entirely with footnotes that continually impede the reader’s progress, without adding much additional substance, and make it nearly impossible to follow the line of argument at points. The reader can do the math: the introduction consists of ninety-eight pages with 345 (!) footnotes. To make matters worse, the vast majority of these footnotes are, quite frankly, unnecessary. Apparently, Vanberg never met a block quotation he did not like. Rather than merely providing a citation to the locations in some work where a relevant idea can be found, Vanberg tends to provide a full quotation, or two, if not three! So, here is a piece of advice that I would never give under normal circumstances: skip the footnotes in the introduction entirely. Read the text of the introduction. It is easy to follow when you are not being bounced three or four times per page to some long block quotation that often only repeats in different words what is in the text. If necessary, come back to the footnotes later, if further clarification is needed.

The substantive complaint is that Vanberg’s introduction does little to advance our understanding of either the context within which Hayek developed his psychological ideas or the exact nature of the contribution that he took himself to have made to psychological science. It is perhaps true that most readers of the volume will be primarily interested in the relationship between Hayek’s psychology and his work in the social sciences, and, thus, that Vanberg’s focus on this relationship is entirely justified. Nonetheless, this leaves several interesting questions unanswered and, it might be argued that, in a volume dedicated specifically to theoretical psychology, these, and not questions about the relationship between Hayek’s psychology and social science, are the ones most in need of answers.

What was the state of German-language psychological science when Hayek first developed his ideas on the nature of consciousness in the early 1920s? At the time, at least at the University of Vienna, psychology remained under the auspices of the philosophy department. What does this mean for the fact that both of Hayek’s most significant psychological works, the 1920 essay and TSO, conclude with discussions of the philosophical implications of his psychological analysis? Whose work did Hayek intend to address with his early theory of consciousness? Upon whom did he mean to build? Which tools, which elements, of previous psychologists did Hayek adopt in constructing his theoretical synthesis? Vanberg repeats the timeworn suggestion, often made (including by Hayek) but never satisfactorily explicated, that Hayek’s theory of consciousness was inspired by his reading of Ernst Mach’s sensory psychology. This is a true, but partial and, ultimately, unsatisfying answer. On Hayek’s (p. 382) own testimony, the greatest of his psychological forerunners was Helmholtz. Yet, to my knowledge, no one has ever asked what Hayek might have taken over from Helmholtz or, for that matter, from his student Max Planck, who himself had a student, a physicist-cum-philosopher, named (wait for it) Moritz Schlick, whose early philosophy (read psychological philosophy) was the first Hayek claimed to understand.^{Footnote 1}

Given the remarkable similarity between the early theory of consciousness and TSO, it might also be asked: What happened (or did not happen) to psychological science in the years separating these two works such that the answer Hayek gave in 1920 remained, he believed, fully viable almost thirty years later? A glance at the footnotes and name index to TSO suggests that, when Hayek returned to his psychology in the 1940s, he relied almost entirely on the work of one man, Edwin G. Boring, for his updated knowledge of the discipline, especially Boring’s then-canonical Sensation and Perception in the History of Experimental Psychology (1942). It seems that Hayek looked to Boring’s book for references to recent literature relevant to the central themes of his theoretical psychology. A close study of Boring’s book would thus appear essential to understanding Hayek’s conception of himself as a theoretical psychologist. In Boring’s (1953, pp. 182–183) mostly favorable review of TSO, he wrote:

The project described in the italicized passage would have fit nicely in an introduction to Hayek’s theoretical psychology. As Boring indicates, Hayek himself did not do this work in TSO, and neither has it been done elsewhere in the secondary literature. Unfortunately, Vanberg’s otherwise excellent introduction does little to advance our understanding of Hayek qua psychologist. This work remains to be done.

Of course, this is less a criticism of Vanberg’s introduction as received than an expression of disappointment that another was not delivered in its place. Anyone who does not share my admittedly idiosyncratic predilections for particular aspects of Hayek’s oeuvre and the related secondary literature will surely find more to criticize in the present review than in Vanberg’s introduction.