Tuominen’s book (based on her doctoral dissertation at the University of Helsinki) sets out to discuss an important and difficult problem: the way in which the ancient philosophers understood the starting points ( archai) for knowledge, i.e., that from which the acquisition of knowledge of the world proceeds. It was a common assumption among the non-skeptical philosophers in antiquity that such starting points exist and that we must have knowledge of them if we want to have knowledge of anything else. They offered various theories about their nature and about the process by which we come to know them, and Tuominen endeavors to provide a synoptic view of the most important among these theories.
The scope of her study is fairly comprehensive: it covers the period from Plato to Philoponus, and it discusses a number of epistemological and psychological doctrines which have all been subject of detailed scholarly studies. Despite such an ambitious program, the book is carefully structured around a few central issues and ideas. It is divided in two main parts, I: Platonic-Aristotelian Tradition (pp. 15-216) and II: Alternative Approaches (pp. 217-287), where Tuominen deals with some main trends in Hellenistic philosophy. Thus she detects two main traditions in ancient thinking about starting points for knowledge, which differ in some crucial respects. On the one hand, the Platonists and Aristotelians assume a kind of metaphysical realism. They believe that reality has an intrinsic order which is independent of us, and that it basically consists of intelligible elements (forms). Within such an order, things are ordered by ontological priority, and there are some things that are primary in the sense that they are explanatory of all other things in the structure, so that they provide the starting points for our knowledge of reality. On the other hand, the Hellenistic philosophers abandon such metaphysical assumptions and, consequently, put forward different criteria for knowledge, insisting, most importantly, that an adequate answer to the skeptical challenge is required if one is to claim knowledge of reality. (There are some further differences between the two traditions, which Tuominen discusses at pp. 220-222.)
In part I, Tuominen draws some further distinctions within Platonic-Aristotelian thinking about archai for knowledge. Her central idea is that we can discern two ways in which archai were discussed in that tradition. First, they were discussed from the point of view of the role they play in argumentation. This is the topic of the first chapter of part I (Theories of Argumentation, pp. 17-153). If we consider archai from the point of view of argumentation, we can distinguish three main subcategories. First, there are starting points from which we begin to inquire into things. Then, there are metaphysical starting points: explanatory truths which express the nature of things, towards which the inquiry is directed. Finally, there are some general logical principles that guide the inferences, but which are rarely explicitly formulated.
The distinction between the first two kinds of principles is based on the assumption that the order in which we come to know things is opposite to the order in which reality is structured. That is, we are first acquainted with facts that are in need of an explanation, and then engage in an inquiry to find some more basic facts that may serve as explanations. Such an assumption is recognizably Aristotelian: it is clearly stated in Aristotle’s distinction between things that are better known to us and those that are better known by nature. The former are expressed in conclusions of scientific proofs, whereas the latter are expressed in premises we are supposed to find in scientific inquiry. Thus, in Aristotelian science, we begin with conclusions of syllogisms, e.g. “The moon is eclipsed” (this is better known “to us”); then we want to find out why it is eclipsed, i.e. the explanation, and it is expressed in premises, e.g. “A celestial body which is shadowed by the earth is eclipsed; The moon is shadowed by the earth” (these are better known “by nature”). Thus, we are searching for premises, since we want to know the explanations. In her discussion of Aristotle’s theory of science (pp. 68-112), Tuominen shows how this idea is developed in his treatment of the notion of proof in the Posterior Analytics. The background for such a conception of starting points for knowledge is provided by Plato, esp. in his discussion of the methods of hypothesis and collection and division (pp. 22-35).
In Chapter 1 Tuominen also discusses some later developments, notably several Platonists (Galen, Alcinous and Plotinus) and commentators on Aristotle (Alexander of Aphrodisias, Themistius, Philoponus, Simplicius), with a view to showing how the distinction between starting points from which inquiry proceeds and those to which it aims is preserved in these traditions. Particularly worth mentioning is her analysis of the manner in which the commentators explain the seemingly contradictory accounts of the distinction between priority to us and priority by nature that can be found in Aristotle (cf. for instance Posterior Analytics I.2 and Physics I.1). None of them assume that there is a real contradiction here, but point to the various meanings of the term ‘universal’ in the relevant passages.
Thus, from the argumentative point of view, principles of knowledge are the first premises of explanations. However, the premises can serve as principles only if they accurately represent things in the world, i.e. “if we are capable of referring to external things in an appropriate way” (p. 155). Consequently, the principles of knowledge must also be considered from the point of view of the question how, in general, we come to know things in the world, or from the perspective of psychology, and this is the topic of the second chapter of part I (Intellectual Apprehension, pp. 155-216). According to Tuominen, “[t]he main epistemological upshot of the psychological theories is that there is a natural cognitive process taking place in all human beings through which we gain initial ‘knowledge’ of what kinds of things there are in the world. Such initial knowledge can be used to initiate inquiry into the nature of things in more detail” (p. 156). It turns out, then, that argumentative and psychological perspectives on starting points for knowledge are closely connected, even though they are usually developed independently.
In this chapter, Tuominen discusses some of the most important ancient theories of perception (pp. 162-175) and intellection (pp. 175-215). A special attention is paid to Aristotle’s account of the transition from perception to intellection in the final chapter of his Posterior Analytics (II.19) (pp. 181-184). In Chapter I, APo. II.19 has been discussed in the context of Aristotle’s ideas about premises of scientific proofs (pp. 103-110). Tuominen has some interesting things to say about this vexed and much discussed text. Thus she insists, quite correctly in my opinion, that APo. II.19 should not be understood as a description of scientific methodology, i.e., as an answer to the problem how we can find the premises in the scientific inquiry. Rather, it should be taken psychologically, as a description of the manner in which we acquire a universal content in our soul. This process is not inferential, but quite natural: “Aristotle’s approach is not normative; he is not concerned with the question of how generalisations can be justified” (p. 183).
Turning to some details of the text, Tuominen is also right in taking 99b36-100a3 as an account of how some animals acquire a rational capacity ( logos). It is not equally obvious, however, that it is this same capacity that is responsible for the apprehension of what she calls a genuine universal and that is later (100b8) identified with intellect ( nous), as she seems to assume (cf. p. 182). While the intellect is always correct, the same cannot be said of logos taken as a rational capacity in general. Thus, it seems that the text can be given a better sense if we take it that throughout the chapter Aristotle operates with a distinction between logos and nous and that, perhaps, he offers two separate accounts of how each of them is acquired (at 99b36-100a3 and 100a3-9 respectively).
As in Chapter I, Tuominen concludes with a survey of some developments in Platonism (Galen, Alcinous, Plotinus) and among Aristotle’s commentators (Alexander, Themistius, Philoponus).
The second part of the book discusses how the starting points for knowledge were treated in Hellenistic philosophy. Tuominen tackles some of the central issues in Hellenistic epistemology, including the debate over the notion of a criterion of truth, the problem of the transition from the evident to the non-evident, Pyrrhonian skepticism, and the dispute between medical empiricists and rationalists. Somewhat surprisingly, in her treatment of Pyrrhonism, she does not discuss Agrippa’s modes, which are highly relevant for her topic.
The book ends with a Conclusion, extensive Bibliography (which contains more works than are actually cited in the text), and indexes.
In sum, Tuominen has written a useful and informative account of some of the most important issues in ancient epistemology and psychology. While the reader may feel that the book would have benefited from editing that would shorten some longer portions of text (e.g. on Aristotle’s dialectic, pp. 38-59) or make it less comprehensive, it is clearly written and well-argued. This makes it accessible to students and specialists of ancient philosophy as well as to those interested in historical roots of some modern debates on knowledge and the nature of mind.
I have spotted some thirty typographical errors, but none that will cause trouble (but note that “Corcoran, J. (1983)” in Bibliography, p. 299, should read “Couissin, P. (1983)”).