[Authors and titles are listed at the end of the review.]
Twentieth-century philosophers drew on De Anima as an escape route from the paradoxes of materialism and mentalism that emerged within post-Cartesian philosophy of mind. Cohoe’s introduction suggests that by situating their readings of Aristotle within then-contemporary debates, philosophers tended to downplay the complexities of his views and isolate Aristotle’s psychology from his biological, physical, and logical works. In this century, philosophical accounts of mind have emphasized the continuity between cognition and other biological processes, while developments in metaphysics and the philosophy of science have demanded non-reductive and multi-level accounts of causation. As a result, much of the older scholarship on De Anima appears to do justice neither to Aristotle’s psychology as such nor to its relevance to contemporary questions about the nature of cognition. The thirteen chapters of this volume aim to remedy this situation by presenting a range of views on De Anima and by framing their discussions in terms of the whole Aristotelian corpus.
Reeve’s opening chapter concerns the domain of Aristotle’s psychological science. Reeve observes that, unlike some modern psychologists and philosophers, Aristotle takes the soul to be a principle of life. Consequently, according to Reeve, the subject matter of De Anima has “its feet in botany” but “its head” in theology, the science of unchanging, separable things (15). Drawing an analogy with the common principles of mathematics, which apply to things in more than one genus, Reeve argues that the soul is a trans-generic entity, the principle of life for creatures falling under distinct genera, and consequently that knowledge of it is a trans-generic science. Reeve goes on to outline Aristotle’s conception of science more generally, concluding that De Anima is an exercise of “honest” dialectic, which contributes starting points to other, genuine sciences. This is an interesting proposal; but common principles in mathematics apply to objects qua magnitude or qua number, that is, insofar as they are or have quantities. That objects in different genera have quantities does not imply that mathematics itself is a trans-generic science. Moreover, Reeve’s reading does not clarify why investigating the soul as the principle of living things should contribute especially to the knowledge of nature (DA 402a5-6).
Chapters 2-4 focus on Book I of De Anima. In Chapter 2, Carter clarifies that Aristotle’s discussion of his predecessors’ definitions of the soul in Book I does not aim to reconcile them with the beliefs of the wise or the many. Rather, in criticizing them, Aristotle shows that souls are not uniform in kind generally – e.g., the soul of a giraffe and of a tree are heterogenous – and thus sets the foundation for his own positive account in Book II (48-49). In Chapter 3, Scheiter takes up Aristotle’s enigmatic claim that nous is not separable in magnitude (DA 429a10-12). In Scheiter’s view, by raising objections to a Platonic conception of nous-as-magnitude in Book I, Aristotle undermines the idea that nous must have a bodily organ to be actualized (64). While this does not resolve the subsequent question of whether nous is separable from body, it entails that a coherent account of thinking will be different in kind from that of the individual senses. Shields’ Chapter 4 is a careful discussion, deeply informed by the ancient commentary tradition, of the connections between the theories of soul-as-harmony Aristotle criticizes and his own hylomorphic conception of the soul. For Shields, these theories are startingly similar: both understand the soul as a normative logos or ratio of a mixed body. The difference between them concerns Aristotle’s understanding of the soul as final cause: in his theory, as opposed to the harmony theories, the ratio is established for the sake of the soul’s activity. What emerges from this discussion, then, is the nuanced view that in formulating his own, hylomorphic, conception of life Aristotle at the same time imitates his rivals and attributes a “radical intrinsic teleological priority to the soul” (86). Collectively, these chapters make a vigorous case against the facile view that the first book of De Anima merely rehashes the views of Aristotle’s predecessors. Even as Aristotle brackets some key questions about its nature, he makes substantive claims and arguments that contribute to our understanding of the soul.
The following chapters turn to Book II, starting with Frey’s examination in Chapter 5 of the soul’s unity. Frey focuses on Aristotle’s claim, concerning his hierarchical conception of the soul, that the lower powers are “in” the higher powers, e.g., that the nutritive power is present in potentiality in the power of perception (DA 414b28-32). Drawing on examples from Aristotle’s mathematics, biology, and chemistry, Frey argues for a single-movement theory, according to which “the unitary soul is the principle of a single movement of a naturally continuous body” (102). In this view, the form of a mixture is analogous to an organism’s soul, since both serve as a principle and end of a singular, continuous movement (103). Thus, from the body’s embryonic development to its last breath, one’s soul possesses nutritive and perceptual powers in capacity, even before one has developed the organs necessary for actualizing those powers. I am not convinced. Why think that a hippopotamus embryo possesses characteristically hippo-nutritive and hippo-sensory powers in capacity that are not possessed by the materials that give rise to the embryo? Continuous movement cannot be the criterion here, since those materials are already mixtures that have natural motions arising from the hippopotamus life-process. To get to Frey’s view, one must assume that the embryo, but not the material that gives rise to it, is a naturally continuous body, though Aristotle never makes such a claim.
In Chapter 6, Gelber asks why, according to Aristotle, nutrition, growth, and generation are all activities of the same capacity, the threptikē psychē. (104). The answer, borrowed from recent scholarship, is that these processes are continuous in Aristotle’s biology (106). In explaining how these processes are continuous, Gelber analyzes Aristotle’s conception of seed as that out of which living things come to be. For Aristotle, in sexual reproduction, semen has motion in actuality, and acts as a tool upon the matter of the female’s seed, similarly to how a carpenter’s tools act upon wood. In blooded animals, the sperm exercises its motions in producing the heart, the source from which the embryonic animal makes itself grow. The principle of this organ, threptikē psychē, then acts as the generator of the animal’s parts, ordering the processes of development through its use of cold and heat as tools (119). The image one gets is that of an internal craftsman, employing cold and heat in producing the animal as its product. Gelber argues persuasively that while generation, growth, and nourishment come to be distinct functions in the fully developed organism, their physiological unity in the generation of animals explains why they are functions of the threptikē psychē.
The following chapters, 7-9, deal with some of the most controversial aspects of Aristotle’s theory of sensory perception. Corcilius (Chapter 7) argues that Aristotle’s understanding of perception as the reception of a perceptual form “without the matter” can only be taken as a definition when one understands the qualification that such reception takes place “according to the proportion” (DA 424a17-24). Johnstone (Chapter 8) proposes that Aristotle’s notorious distinction among three kinds of perceptible things – the special, common, and accidental – depends on his understanding that bodies have their sensory qualities not on account of their minute geometrical and kinetic features (à la Descartes) but in virtue of their underlying chemical constitutions (171). Ierodiakonou (Chapter 9), drawing on Aristotelian texts and the commentary tradition, suggests that there is an intrinsic connection between reflective awareness (your ability, from hearing a C-sharp, to be aware that you are hearing it) and perceptual attention (your ability to focus your attention on the flute’s C-sharp by ignoring the conversation at your table). These chapters are full of provocative suggestions and helpful references to the large and unruly literature on Aristotelian perceptual theory.
One point in Corcilius’ interpretation of Aristotle’s perceptual theory is problematic. Corcilius denies that Aristotle’s threefold taxonomy of special, common, and accidental perceptibles amounts to an ontological distinction and maintains that perception is an awareness of aisthēta, understood as ordinary, 3D objects. This is a salutary thesis insofar as it shows that Aristotle’s conception of perceptual change is a species of physical change described in the Physics. Yet perceptual change differs from ordinary change in respect of its mediation, which separates the cause from the awareness of the cause: for example, if “my leg feels the cool of an ice pack on it”, this “does not make me aware of the freezer that cooled the ice” (142). As Corcilius has it, you discriminate the perceptual stimulus of the ice pack insofar as you discern its coolness, in virtue of your proportion, and without reference to the source of the stimulus. But where is the proportion? To perceive its coolness, your leg must be warmer than the ice pack. In this change, your fleshly leg takes on the coolness without its becoming ice. So, the cooling of your leg seems to satisfy Corcilius’ criteria for perceptual change, insofar as you take on the form without the material. Yet this does not require any perceptual awareness of that change: you might fail to notice the cooling of your leg, despite the reception occurring “according to proportion”. If this result is to be avoided, there must be something more to perceptual discernment (krisis) than is explained here.
Chapters 10-13 turn to De Anima III. Twomey (Chapter10) takes on the difficult literature on phantasia to argue, quite convincingly, that Aristotle understands error to emerge from phantasia rather than from perception as such. Kelsey (Chapter 11) asks what is it that makes intelligible things (ta noēta) intelligible, and thereby engages some of Aristotle’s most perplexing statements: that ta noēta are immaterial essences and are identical with thinking in activity. These claims are not easy to understand, yet Kelsey offers a lucid treatment, arguing that, in a sense, in thinking the essence of a thing, one thinks one’s activity in understanding it (224). Cohoe (Chapter 12) makes a direct attack on perhaps the most contested topic of De Anima, arguing that nous is separable not only de dicto, but also de re, from the body of a living animal. This chapter is programmatic, analyzing Aristotle’s arguments on the separability of nous in several texts, including the crucial chapters III.4 and III.5 of De Anima. Yet despite its survey of the evidence, Cohoe ignores the most promising arguments against the de re separability of nous, those of E. R. Jiménez, Aristotle’s Concept of Mind (Cambridge University Press, 2017) (see Chapter 3). By sticking to friendly sources, this chapter misses an opportunity to face those who read the relevant passages quite differently.
The last chapter is the only one concerning self-motion, which is, with perceiving, a distinguishing characteristic of living things (DA 403b25-27). This is unfortunate, since one needs a critical guide especially in these convoluted final pages of De Anima. Moss (Chapter 13) compares Aristotle’s opposition of phantasia to nous in decision-making to Dual Process Theory’s Type 1 and Type 2 cognition. Moss adduces impressive textual evidence to support this analogy and makes some interesting observations on the practical implications of Aristotle’s psychology. Yet the main doctrine of Dual Process Theory, that people tend to make different decisions when they react quickly and automatically than they do when they reflect on their beliefs and desires, is hardly illuminating. Moreover, Dual Process Theory is an idealized model of cognition, meant to conform cases of “irrationality” to “rational actor” theory in social science. Aristotle’s aim is quite different: his philosophical biology describes the characteristic activities of human beings in their essence. His goal is to shed light on the principle by which we move ourselves and perceive the world, and thus on what it is to be alive.
This volume is mostly successful in achieving its stated goal. The book offers a number of well-researched and philosophically interesting engagements with Aristotle’s text. However, Aristotle’s work is concerned with how animals cognize and with how they move themselves. By focusing almost exclusively on the former question, this volume may give rise to the misconception that De Anima is more aligned with our current conception of psychology than it really is. Nevertheless, Aristotle’s On the Soul: A Critical Guide represents an important step towards showing that Aristotle’s ideas are relevant to twenty-first century investigations of the mind.
Authors and Titles
Introduction, Caleb M. Cohoe
- Hylomorphic Explanation and the Scientific Status of De Anima, C.D.C. Reeve
- Aristotle on Earlier Definitions of Soul and Their Explanatory Power: DA I.2-5, Jason W. Carter
- Why Nous Cannot Be a Magnitude: De Anima I.3, Krisanna Scheiter
- Souls among Forms: Harmonies and Aristotle’s Hylomorphism, Christopher Shields
- Aristotle on the Soul’s Unity Christopher Frey
- Aristotle on Seed, Jessica Gelber
- The Gate to Reality: Aristotle’s Basic Account of Perception, Klaus Corcilius
- Aristotle on the Objects of Perception, Mark A. Johnstone
- Perceptual Attention and Reflective Awareness in the Aristotelian Tradition, Katerina Ierodiakonou
- Phantasia and Error, Rosemary Twomey
- Intelligibility, Insight, and Intelligence, Sean Kelsey
- The Separability of Nous, Caleb M. Cohoe
- Thought and Imagination: Aristotle’s Dual Process Psychology of Action, Jessica Moss