Aristotle on the Soul

  1. Aristotle uses his familiar matter/form distinction to answer the question "What is soul?"
  2. In the case of substances, we can distinguish
    1. Matter (potentiality)
    2. Form (actuality)
    3. The compound of matter and form
  3. Aristotle is interested in compounds that are alive. These -- plants and animals -- are the things that have souls.
  4. Their souls are what make them living things.
  5. So the soul is the form of a living thing. (Not its shape, but its actuality, that in virtue of which it is the kind of living thing that it is.)
  6. Actuality (entelecheia): there are two kinds.
    1. First actuality ("as knowledge is").
    2. Second actuality ("as contemplation is").
  7. An analogy:
  8. First actuality is thus a capacity to engage in the activity which is the corresponding second actuality. So soul is a capacity -- but a capacity to do what?
  9. A living thing's soul is its capacity to engage in the activities that are characteristic of living things of its natural kind.
  10. What are those activities? Some are listed in DA II.1; others in DA II.2:
  11. So anything that nourishes itself, that grows, decays, moves about (on its own, not just when moved by something else), perceives, or thinks is alive. And the capacities of a thing in virtue of which it does these things constitute its soul.
  12. The soul is what is causally responsible for the animate behavior (the "life activities") of a living thing.
  13. The degrees of soul:
    1. There is a nested hierarchy of soul functions or activities (413a23).
      1. Growth, nutrition, (reproduction)
      2. Locomotion, perception
      3. Intellect (= thought)
    2. This gives us 3 corresponding degrees of soul:
      1. Nutritive soul (plants)
      2. Sensitive soul (all animals)
      3. Rational soul (human beings)
    3. These are nested in the sense that anything that has a higher degree of soul also has all of the lower degrees. All living things grow, nourish themselves, and reproduce. Animals not only do that, but move and perceive. Humans do all of the above and reason, as well.
    4. There are further subdivisions within the various levels, which we will ignore.
  14. The soul is not separable from the body. (Aristotle waffles on the intellect.) But the soul is not material.

    " . . . the soul does not exist without a body and yet is not itself a kind of body. For it is not a body, but something which belongs to a body, and for this reason exists in a body, and in a body of such-and-such a kind" (414a20ff).
  15. Aristotle's picture is not Cartesian:
    1. There is no inner/outer contrast. The soul is not an inner spectator, in direct contact only with its own perceptions and other psychic states, having to infer the existence of a body and an "external" world.

      There is thus no notion of the privacy of experience, the incorrigibility of the mental, etc., in Aristotle's picture.
    2. The soul is not an independently existing substance. It is linked to the body more directly: it is the form of the body, not a separate substance inside another substance (a body) of a different kind. It is a capacity, not the thing that has the capacity.

      It is thus not a separable soul. (It is, at most, pure thought, devoid of personality, that is separable from the body on Aristotle's account.)
    3. Soul has little to do with personal identity and individuality. There is no reason to think that one (human) soul is in any important respect different from any other (human) soul. The form of one human being is the same as the form of any other.

      There is, in this sense, only soul, and not souls. You and I have different souls because we are different people. But we are different human beings because we are different compounds of form and matter. That is, different bodies both animated by the same set of capacities, by the same (kind of) soul.

Go to previous lecture on Matter, Form, and Substance.

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