Aristotle’s Soul

Aristotle presents a conception of the soul that is fundamentally materialist. Unlike Plato, who understands the worth of a soul in terms of its ability to transcend the material and physical world, Aristotle understands the soul as at root inseparable from the material world. Despite his difference in conclusions and methodology from Plato, Aristotle seems to agree that the function and nature of the soul is an important philosophical theory worthy of analysis. In his work, De Anima, Aristotle examines the nature of the soul as a question of biology. It is not a work of metaphysics in the same sense Plato is doing metaphysics; instead, Aristotle understands the analysis of the soul as part of the analysis of a living thing. Aristotle outlines three several different potentialities of the soul, the three most important being: nutritive, perceptive, and understanding. This reinforces his fundamentally biological conception of the soul, as plants have only the potentiality of the nutritive soul, animals both the sensitive and nutritive souls, and human beings have all three potentialities.

This paper will first outline Aristotle’s conception of the soul and then raise two key criticisms. First, Aristotle’s account of perception seems to indicate that the soul becomes “like” the object it perceives. The extent and nature of that similarity is unclear and problematic. The second problem is not so easy to resolve. Throughout the entirety of De Anima, Aristotle appears resolute in arguing that the soul is inseparable from the body and the immortality, as it is commonly understood, is not a quality of the soul. Yet, on page 867, he discusses that there is a form of the intellect that it is immortal and everlasting. This paper will make the argument that this is fundamentally in conflict with the rest of his conception.

Aristotle begins De Anima with a discussion of his methodology. He argues that the first question is to determine the soul’s “genus and what it is”. In other words, does it have the qualities that Plato attributes to it when he writes that the soul is “deathless, intelligible, uniform, indissoluble, always the same as itself”? Aristotle seems to be criticizing Plato and other thinkers like him when he says that those who discuss the soul seem to “only examine the human soul”. He raises a great many questions about the essence of nature of the soul, but then seems to indicate that the question can not originate with the determination of the essence of the soul. Instead, it is necessary to first evaluate the different properties of the soul, since “a definition will clearly be dialectical and empty unless it results in knowledge, or at least ready conjecture, about the coincidental properties”. This is very different than Plato’s exploration in the Phaedo, where he simply examined the relationship between myth and philosophy and posited the soul as an opposition to the body, situating it as inherently different and determining its properties from an argument about what its essence might be. Aristotle, on the other hand, wants to look at the actions and qualities of the soul and from them deduce what the nature of it must be.

The first implication of this difference in method is immediately obvious. Aristotle begins by discussing the fact that the body is a prerequisite to the soul being affected or acting. Even understanding, or the functioning of the intellect, is dependent on the body insofar as it requires the ability to sense appearances. Aristotle agrees, in a sense, with the Phaedo insofar as the soul is very different than a body. But he does not seem to think that the soul is a Form in the same sense that Plato does. Aristotle defines the soul, somewhat opaquely, as “substance as the form of a natural body that is potentially alive. Now, substance is actuality; hence the soul will be the actuality of this specific sort of body”. In order to unpack what it is exactly that Aristotle thinks the soul is, however, it is important to understand the way Aristotle talks about actuality and potentiality. Aristotle offers an illustrative metaphor when he writes “we need not ask whether the soul and body are one, any more than we need to ask this about the wax and the seal”. We speak of the wax and the seal in different ways, but they are merely different valences on the same thing. The seal is the pattern of wax, it is the thing, whereas the wax itself is simply the matter of the thing. He further clarifies by discussing the eye. An eye is not an eye unless it can see; sight is the “soul” of an eye, without which it would simply be a replication or somehow artificially similar. This seems to create a sense in which the soul is the purpose or “idea” of a thing, insofar as it is what the arrangement of material aspects is put together to fulfill.

This is simply the most general account of the soul, however. He further clarifies by talking about the first potentiality of the soul, which is that which allows for nourishment. Plants and animals are alive in the sense that they can grow and that they stay alive as long as they can absorb nourishment. It is important to clarify that this is not a different type of soul than the types of souls that animals or humans have. Instead, these are the different potentialities that are possible based on the actualities of the relationship between the soul and the body. The soul and the body are not just in fact inseparable, they are in principle inseparable insofar as the qualities of the soul are only derived from it being in the proper sort of body. These different potentialities of the soul are mutually dependent in different ways. All living things are in possession of the nutritive element and the rest of the types of souls depend on it. Some things are locomotive and “most rarely, some have reasoning and understanding”. This is a deep distinction between Plato and Aristotle. Plato is specific about the soul being singular, uniform, and indivisible, whereas Aristotle seems to conceptualize understanding of different parts of the soul as foundational to understanding the soul at all.

Aristotle speaks of the soul being the cause of the living body in three ways “as the source of motion, as what something is for, and as the substance of ensouled bodies”. It is the cause of substance in the sense that living things are alive, in nature, and the soul is the principle of that living-state. It is also the cause of what something as for, as the soul is the natural end of a living thing. Just as the earlier example of the eye demonstrates, there is a sense in which the soul is the purpose of a creature. The last way one can understand causation is the source of motion and insofar as locomotion is possible by a living things, the soul is the source. The first important aspect of the soul is the nutritive capacity, as all living things possess it. Even the discussion of this capacity distinguishes him deeply from Plato, as Plato was unconcerned with the material bodies that housed souls. Indeed, he understood the soul and the knowledge of the soul as fundamentally distinct from the knowledge of physical bodies. Aristotle, on the other hand, is discussing things as concrete as growth and digestion. Nourishment is a way of understanding the preservation of ensouled things, equipping the potentiality of the soul into an actuality. The soul in this sense causes life because it is the only means by which life is able to continue.

The second and critical aspect of the soul is the perceptive part of the soul. Perception occurs in being affected, so it is a type of change from the normal state. But the question remains about what sort of relationship leads to the proper type of being affected and is therefore interpreted as perception. The perceptive part exists in merely potential and it necessitates something about the world in order to actually perceive; hearing is the potential of my ears, but if it is utterly quiet, the hearing will never become actual. Each type of object has a type of sense that is capable of being perceived by “sight, for instance, is of color; hearing of sound; taste of flavor”. Perceiving is a way of being affected and “hence the agent causes the thing that is affected, which potentially has the quality that the agent has, to have that quality actually”. This is perhaps the first problem with the account thus far. In what sense does the perceiving object become like the perceived object. On face, this seems impossible. Is this to say my tongue becomes like a carrot if I taste the carrot? Or my eyes become in some sense the color blue from looking at it? Even if we take seriously the idea that a sense receives “the perceptible forms without the matter”, it still seems curious to say that the potentiality of the sense organ is continually in shift when it is confronted with different sense objects.

Additionally, how are we to distinguish this for of change from change between objects that is clearly not an instance of perception. For instance, if I put fire next to a piece of paper (which is a non-living thing), the paper would be affected and become like the fire. There is no sense in which the paper is sensing the fire, however. If it is the case that “nothing that is incapable of smelling anything can be affected by odor, then perhaps it is necessary to say that the paper is sensing the fire. Aristotle only seems to briefly address this concern when he writes, “Perhaps smelling is <not only being affected, but> also perceiving, while air that is affected <by odor>, by contrast, soon becomes an object of perception <not a perceiver>”. That is to say, it seems that here Aristotle is saying that one perceives not only be becoming affected by the object of perception, but in some sense being capable of recognizing that one is affected. This is interesting, because it makes a quality of sentience critical to Aristotle’s notion of perception; one can only perceive, if this is the case, if one is aware that one is perceiving.

The last aspect this paper will address is the understanding faculty. The intellect must be unmixed, and like Plato, Aristotle considers the soul to be the place of the forms. However, Aristotle seems to think that it is impossible to have any thoughts or understanding, even abstract thoughts, without perception. The soul is in this sense inseparable from the body. However, this leads us to the second concern that this work raises. Throughout the entire work, Aristotle has been arguing that the soul and body are inseparable, making any understanding of the immortality of the soul in a Platonic sense impossible. However, then he says that the intellect must necessarily be valuable than the things it perceives and this part of the intellect is “immortal and everlasting”. This part is hard to even decipher; it is entirely unclear what precisely he is saying. One possibility, to maintain the consistency with the rest of the work, is to take seriously the idea that once this part of the intellect is immortal and everlasting is impossible to be affected and is therefore, utterly beyond the knowledge of individual. If that is the case, however, how can they interact and how is it possible for the perishable intellect to be able to use the capacity of the productive intellect to understand. There seems to be no way to resolve this contradiction, at least in the text.

Aristotle in many ways moves past Plato’s understanding of the soul, to one that is more empirical, realistic, and based in material reality. He claims that all living things have different aspects of souls and that the soul is nothing without being in the body, like the wax and the seal. This understanding of the soul as potentiality makes this section about the immortal and everlasting productive intellect even more curious, however, because that seems to be a return to the Platonic conception and utterly inconsistent with the rest of the paper. Aristotle, until that point, had been very clear to differentiate himself from thinkers of the soul that had come prior, particularly in terms of the importance of materiality. Nonetheless, despite the confusion in that section, this work in general is a fascinating progression on the concept.