The Brute Within proceeds in three parts, the first two (amounting to half the book) on Plato and the third on Aristotle. Each part, as well as the book itself, has an Introduction in which Lorenz helpfully signals what he is up to; the author frequently (though sometimes repetitively) summarizes his argument as he goes along. There is no mistaking his central claims: that in both Plato and Aristotle there are three types of desires—reason, spirit and appetite—such that the last two may motivate conduct without any participation in reason at all. In human beings, reason may itself motivate conduct and also may share information with appetite and spirit to modify behavior.
It is a significant virtue of the book that Lorenz takes great care in offering his often novel readings of many interpretative cruxes in Plato and Aristotle, engaging in conversation with much recent Anglo-American analytic commentary (the doctoral research on the topic was done at Oxford). No one writing on ancient philosophical psychology will want to ignore the detailed, often painstaking, work available here. Indeed, the index locorum will be of assistance to any commentator on particular texts, with what must be a thousand references to lines as well as pages in the relevant works of Plato and Aristotle. In Part One, on reason and appetite in the Republic, Lorenz’s discussion has a spiral-like quality, signaling his differences with commentators, then working through those points in successive chapters. So, in Ch. 1, Parts of the Soul, Lorenz claims that Plato is not just distinguishing different motivations in human psychology (as some commentators hold) and not just pointing to conflict between them; rather, Plato sees motivational conflict as explicable only by positing that the soul has parts—three incomposite parts, in fact—constituting a unified person whose appetite and spirit do not participate in reason at all.
Ch. 2 considers the Argument for Tripartition, nicely pointing to passages where Plato has noted the universality of our desires for money, power and wisdom ( Apology) 29, Phaedo 82) , and arguing that this motivational triplet is the basis for the city’s three classes, not the other way round. That impulses to action arise from distinct parts is established by PO, the principle of opposition given at Republic 436b8-9. Plato treats desire and aversion as directed at the same object; since they are opposites, they cannot arise from one and the same thing. Lorenz deals with the unusual claim that simple thirst is simply for drink, not qualified drink, and agrees with those who see Plato as correcting the Socratic view that all desire is for the good. Plato’s argument starts with a case in which appetite wants to drink, and reason opposes it. Why? Lorenz speculates that reason must be involved here because spirit would be indifferent, not averse, to a desire to drink, whereas reason’s aversion would arise from a conviction that drinking is detrimental in some way. This, of course, requires the convictions that (a) there are only three parts to the soul and (b) spirit is the third. Lorenz has addressed neither of these claims, and only later does he mention briefly the argument for spirit (pp.70-71).
In Ch. 3 Lorenz returns to the notion of partition, confronting the difference between the noncomposite soul of the Phaedo and the composite soul of the Republic. Spirit and appetite require embodiment, so what is the true nature of soul, especially if compositeness makes dissolution possible? The Timaeus, he says, settles the issue: intellect is soul (not a part of soul), with the other two added on as temporary parts. Ch. 4 consolidates Lorenz’s “simple picture” of tripartite soul, over against more complicated rival views in which appetite engages in primitive means/ends reasoning. Lorenz argues that the complicated view goes against PO, denies one kind of reasoning to Platonic reason, and has no explicit textual warrant. Instead he points out that epithumia in Plato includes many kinds of desire, not just appetitive desire; PO works because reason and spirit have their own aversions and motives (thus explaining the oligarchic character of Rep. 8, who needs not have conflicting appetitive desires). Lorenz has to work harder to explain why appetitive soul is called money-loving: given that its primary desires are “most of all satisfied through money” ( Rep. 580e2-a1), shouldn’t it be able to participate in reasoning about means? No, says Lorenz; through social habituation appetite is attached to money itself “as a direct source of pleasure”. Perhaps, but Plato’s other instances of appetitive desire relate directly to embodiment and can be urgings or pleasure-cravings of bodily organs. Not so for philochrêmatia; further, at Rep. 2.357c Glaucon acknowledges that money-making is not desired for its own sake, but in the way that physical training and medical treatment are, i.e. as things onerous in themselves but chosen for their consequences.
Part Two of the book, which is concerned more generally about belief and appearance in Plato, takes us to non-rational cognition. In Ch. 5, Imitation and the Soul, Lorenz deals with Rep. 10’s discussion of imitation and its appeal to the lower parts of the soul. In a detailed reading of two sentences in 602e he argues, against others, that conflicting beliefs about a thing’s appearance and its measurement do not belong to reason but rather to reason and to the parts below reason, which must accept sensory appearances in order to be motivated. Ch. 6, Belief and Reason, notes the denial of belief to appetite in the Timaeus; Plato has come to understand that belief requires a grasp of “intelligibles” that only reason can accomplish. The evidence for this is in the Theaetetus 184-7, to which Lorenz devotes over a dozen pages arguing that perception cannot attain truth; this activity requires “cognitive access to being” (p.78). So, says Lorenz, perception has no beliefs, not even perceptual beliefs. But without some sort of awareness, how can the lower parts of the soul apprehend and seek (for instance) what’s pleasant? Ch. 7 takes us Below Belief and Reason to answer. Plato realizes that while appetite and spirit cannot form beliefs, reason does issue information and commands to the lower parts. In explanation, Lorenz turns to the intriguing picture (in Timaeus 71a3-e2) of the function of the liver in receiving images and mirrored impressions from reason, to control appetite through fear or enticement. Lorenz is concerned that Plato needs, but does not provide, an explanation of how appetite is aware of these representations since, as shapes appearing on the liver, they seem to be external to consciousness (but note that it is not the brain, but reason, which sends these messages down; Plato’s metaphors are mixed here). For that the Philebus is helpful. At 32b9-36c2 Socrates explains pleasures of anticipation, common to all animals, as dependent on memory as stored sensory impressions; at 38e12-40c6 the analogy of the illustrated book, though introduced to account for one type of false pleasure, also explains how human appetite can anticipate pleasure through awareness that is sensory. This provides the key, then, for Lorenz: reason’s messages to appetite, and presumably to spirit, are not simply communicated beliefs, since these cannot be understood by the lower parts; they are sensory impressions which move these parts through pleasure or pain.
Part Three spends a good deal of time on Aristotle’s discussions of desire and action in non-rational animals. Ch. 8 dispenses with some preliminaries: phantasia for Aristotle gives rise to desire, and is itself generated by thought or perception. Since animals lack reason, the role of phantasia in motivating successful animal behavior must be non-rational, but it is not blind either; it often demonstrates interesting purposive cognitive awareness. So the function of phantasia is like thought; and in fact for humans it can, though need not, be rational.
In Ch. 9 the discussion of non-rational motivation is built on two claims arising from the ‘chain of movers’ in De Motu Animalium 8, 702a17-19: (i) forming a desire requires a suitable phantasia, and (ii) perception as well as phantasia is necessary for animal desire. Lorenz insists that Aristotle is dealing here and in De Anima 3.9-11 only with goal-directed locomotion, not desire generally. Further, purposive action is directed to an apparent good, which requires cognitive abilities such as envisaging a prospect not presently obtaining. Perception alone is insufficient: its content is restricted to what is present to the animal, and hence can not represent past or future states. While thought can form purposes for the future, in non-rational animals the work of envisaging prospects must fall to phantasia. This comes about because phantasia, like thought, has the power to present forms apprehended in and retained from past perceptions. Lorenz recognizes, however, that retaining a perception doesn’t itself create a motivating prospect, so he speculates that perception may not simply be of particulars, but rather “patterns or configurations of appropriate sensory characteristics” (p. 137).
Ch. 10 on desire without phantasia provides evidence that claim (i) above in Ch. 9 is restricted to non-rational locomotive desire. Lorenz deals with De Anima 2.3 where the ‘chain of movers’ seems to be broken by the claim that only perception is required for desire. Aristotle does acknowledge that some animals (such as the sponge) perceive, and have aversions, without locomotion; further, he thinks that animals like grubs have no phantasia. Lorenz explains that Aristotle links pleasure and pain directly with perception, especially touch, and pain gives rise immediately to aversion without requiring any envisaging of prospective situations. But at De Anima 3.10-11, 433b27-434a5, Aristotle clearly links the capacity for desire with the capacity for phantasia. Lorenz deals with the inconsistency, not by means of a developmental thesis as other commentators do, but by restricting the scope of the capacities in question to locomotive animals, which do require phantasia to form desires. (The example of grubs, however, remains problematic: they are indeed locomotive and purposively so.)
How does phantasia work? Ch. 11 answers that it, along with perception, is a “kind of thinking” that is purposive. To his earlier account of phantasia as necessarily involving envisaging prospects, then, Lorenz adds that an animal must have phantasiai suitable for their needs and pleasures. Their sensory impressions must be ordered so as to form associations for proper living, but without thought being involved at all. How do dispositions to associate perceptions get formed? Lorenz takes us to De Memoria. A memory involves not just the presence of a phantasia representing a prior past perception, but also an awareness that one had had that perception previously. There’s an intriguing discussion of how remembering intelligibles fits with this theory. There is no organic mechanism for preserving thoughts, hence what one remembers are sensory representations associated with particular intelligibles, which when remembered trigger the thought again (but of course with an awareness that one had had that particular thought). Animals do not have access to intelligibles; but they do have dispositional memory: one sensory affection can trigger the re-activation of a related one because of their associations.
Ch. 12 brings us to Practical Thought to answer the objection that Aristotle should be willing to attribute reason to animals (as does Hume) to explain their purposive behavior. Practical reason requires deliberation about a recognized goal and a grasp of relevant means, including an assessment of other possible goal-relevant actions. Now, Aristotle’s account of animal behavior includes their goal-awareness but not the capacity to grasp why this or that is a means to an end. Hence Aristotle’s denial of reason, deliberation and decision to animals is coherent. Lorenz notes that Aristotle needs to be able to account for the non-deliberative recognition of goals involved in practical reason; but Lorenz himself needs to account for animal goal-recognition since, on his reading, it has no part at all in reason. Animal behavior is not irrational, but, whereas Lorenz claims that though purposive it is not rational, there remains the option that though not fully rational it is derivately so because purposive.
In Ch. 13 Lorenz acknowledges Aristotle’s distinction in the Nicomachean Ethics between strictly rational soul and the “lower part of reason” in which appetite and spirit participate in a kind of rationality. The appetite of the self-controlled person of NE 1.13 is able to obey reason, not through persuasion (which requires beliefs) but through admonition and reprimand (parsed as pleasure or pain, since appetite cannot reason). The account of acrasia in NE 7 is used to explain the difference between spirit and appetite: spirit can come to share in the “evaluative outlook” of reason and follow its commands through a “kind of reasoning”, whereas since appetite is “hardwired”, reason can steer it only through pleasure or pain. Nevertheless, Lorenz maintains that for Aristotle spirit and appetite have no capacity for practical reasoning. In fact they can render reason temporarily impotent while still motivating non-rational purposive action. But, in the well-developed person reason will play an important role in shaping even the ways in which situations are perceived so that the goals of spirit and appetite will accord with reason’s ends.
In his Conclusion, Lorenz brings together his two philosophers: both recognize three types of desire in the soul, but Aristotle rejects Plato’s tripartition. He keeps soul incomposite because he does not take desires to be conflicting motions in the soul, but rather in embodied persons. Aristotle also tacitly corrects Plato’s mistake in the Philebus that desire always requires memory because one cannot in depletion want replenishment without remembering it: on the contrary we can desire what we already have (note, however, that Plato elsewhere does recognize this form of desire, at Symp. 200c-d). Both philosophers share the threefold view that human beings can have motivations that depend in no way upon reason but only upon sense perceptions and memories of those perceptions; that human beings also have the rational capacity to engage in reasoning about ends and means and other relations; and that reason may communicate with appetite and spirit non-rationally in order to shape and control them.
The conclusion is silent about the wider context and implications of this fine study. As noted, much of the argument deals with specific bits of text, not simply with trees rather than forest, but with particular cross-sections of trees. Lorenz does provide a few paragraphs on Empiricism and Rationalism, in which he maintains that Plato and Aristotle combine both in a unified theory of motivation. I take it, however, that the point of distinguishing appetitive and spirited desires is to enable human beings to live in accord with reason, so one wishes for more on the moral psychology of these authors, especially Plato. (His prolific animal imagery, for example, deserves more than a nod in any discussion of the brute within, as does the mitigation of responsibility that seems to be implied in that imagery.) Again, and especially in the case of Aristotle, one wants more explication of terms like “cognition” or expressions like “envisaging a prospect”, which have a great deal of work to do in the argument. But it is the mark of a successful work in philosophy that it spurs more reflection, and we should be thankful that The Brute Within creates a (cognitive) appetite for further spirited thought.