Aristotle's De Anima
- Lived 384-322 BC. Son of a doctor; Plato's greatest
student; tutor to Alexander the Great; wrote dialogues and
lectures of which we have only the lectures; founded an
alternative to the Academy: the Lyceum; died 1 year after the
death of Alexander.
- Aristotle defines substance as the essence of a thing (note
the difference with how we will later use the term "substance":
when we get to Descartes, we will use "substance" to mean a
potentially independent being, a being that can exist alone).
- Aristotle modified Plato's doctrine of the Forms (Ideas,
- For Aristotle, Forms must be in matter (and cannot
in general exist if they are not in matter); and
- Forms can have first and second actuality
(entelecheia). The first actuality is to have the
potential to serve some teleofunction/purpose; the second
actuality is to actually serve that teleofunction/purpose.
- Aristotle's view of nature, or at least of biology, is in
part based on a view that some things have telos, or
purpose. We will use (in this course) the term
teleofunction for a purposeful capability had by some
organism or organ. E.g.: a teleofunction of the heart is to
- Form and teleofunction are essentially related: the
teleofunction of a thing is given by its Form; its Form is
identified by (and is essentially) its teleofunction.
De Anima, background
- Our interest in the book is primarily the notion of
psyche that Aristotle develops. We want to ask, what is
psyche? What kinds of behavior are explained by an explanation
- The book is not well-divided thematically. For our
interests, we can think of it as having the following discussions:
- Book I: Alternative theories about psyche.
- Book II, chapters 1 and 2: Aristotle's view of
- Book II, chapters 3: the psychic hierarchy.
- Book II, chapters 4: nutrition.
- Book II, chapters 5 through Book III chapter
2: sense perception.
- Book III, chapter 3: imagination.
- Book III, chapter 4-8: intellect.
- Book III, chapters 9-11: motivation
- Book III, chapters 12-13: summary, teleology.
De Anima, Book I
- Aristotle describes the topic: the principle of soul.
He uses some of the categories from his work on logic to
ask what kind of thing a soul might be.
- Aristotle opens the question of what kind of account
might be appropriate: a teleofunctional story, or a materialist
- Aristotle typically opens his works with a review and
criticism of leading views on the subject to be discussed.
Aristotle in Book I, Aristotle will describe the topic,
describe some views of others on the topic, and
criticize those views.
- The prior theories of soul are primarily aiming to explain
locomotion and sensation.
- We might divide the targets of Aristotle's criticisms into a
- Primitive substance reductivisms; e.g.,
- Heraclitus: soul is fire
- Diogenes: soul is air
- Critias: soul is blood
- Hippon: soul is semen
- Atomism. Aristotle treats the atomists unfairly,
sometimes as primitive substance reductivists, and
sometimes as simplistic harmony theorists.
- Mixed substance theories. These can be consistent
with theories that believe only like can know like, and
so to know many kinds we need to contain many kinds.
- Harmony theory. Aristotle treats some atomists
as having some form of this.
- Number theory. The soul is some kind of mathematical
- Aristotle rejects each of these theories.
- Many of the primitive substance reductivists
(and, Aristotle claims, some atomists) are
motivated by the idea that if the soul moves an organism
that soul must itself be in motion. Aristotle rejects
this (he even ridicules it).
- Aristotle does some excellent conceptual analysis:
the soul does not move, but rather the soul and matter
together (the man) moves.
- Harmony theory has difficulty explaining the
harmonies we see in, say, organs -- are these
organisms with soul? Whatever unifies organs is the
psyche -- but then it is not just harmony. (This is
an unfair criticism! Aristotle's theory is so close
to the harmony theory he may have been struggling to
distinguish himself from it.)
- To know requires a kind of grasping of the form
of a thing, not its matter; so we don't need like to
- Aristotle leaves open many questions, including whether
the soul has parts.
- There are three kinds of substances (beings): form, matter,
and form and matter together. Aristotle will argue that psyche
is the form of a living thing.
- Aristotle usually says, and says here, you cannot have
form without matter; it follows you cannot have a psyche
without a body. Elsewhere he seems to suggest you can have
mind -- which may be a part of the soul -- without the body.
- What distinguishes things with a soul is that they are alive.
Various living things have:
- Nutrition (the ability to take in food and grow)
- Sensation (which Aristotle does not distinguish
- Mind (Nous)
- This gives Aristotle a hierarchy.
- All living things have nutrition (so plants have
this most primitive soul)
- All animals have sensation (and sensations requires
at least touch)
- Some animals (perhaps only humans) have Mind (Nous)
- Psyche is the first actuality of a living thing (that is,
it has the potentialities of that thing -- a second actuality is to
exercise the capability).
- From B II c5 until BIII c2 Aristotle discusses sensation.
- Senses are potentials for experiences of external things.
Specifically, the are the potential to receive forms.
- Aristotle asks the questions of what something perceived
is there when not perceived. In modern terms: does the tree
falling in the woods make a sound? His answer is that it does
not make an actual, but rather a potential, sound.
- A few of the things he observes are notable:
- Vision needs light, which is the color of transparency.
Light does not travel.
- Hearing is of sound, which is the movement of the
- Touch is a mean between extremes, and so too much or
too little results in some kind of failure of sensation.
- There are only 5 senses, he argues.
Book III (c3 on)
Aristotle considers imagination, mind, and motivation.
- Mind (nous) is not perception/sensation. Dogs have
perception but not nous.
- Imagination is not sensation, nor is it opinion, but
it is rather opinion and perception combined in a way.
- Mind has two parts, a receptive and an active part.
The active part he seems to allow may be able to exist
apart from the body.
- Mind uses images. The active mind making a judgment
decides that an image corresponds to a thing or situation.
- Pathe (motivation) is guided by images or thought, but
necessary for action.
What should we as contemporary philosophers of mind take away from this?
- The notion of psyche is quite distinct from the modern notion
of mind, but it has extremely suggestive differences and similarities.
- The biological focus of Aristotle, and his concern with
teleology, is quite familiar to contemporary concerns.
Some foreshadowing hypotheses
The birth of the modern, scientific world view is the victory of
causal explanation over teleological explanation. However, we are (at
least as of yet) unable to explain biological entities or minds
without teleological explanation. Recognizing this, Descartes divides
the world into the teleological and the causal -- realms of mind and
of body, respectively. Most of the contemporary problems of mind is
concerned with making sense of mental phenomena in terms of our best
theory. I suggest that the reason this seems problematic, and the reason
we struggle with forms of explanation, is that it is yet unclear how
our best theory will explain normativity.
That said, I urge you not to indulge in the common fallacy of denying
the antecedent of a conditional. One cannot reason from these first
two claims to the third claim:
I pick this only as an example, and do not mean to claim that
Descartes was wrong. Rather, I am just pointing out that those who
claim Descartes was wrong should not be read as claiming also that we
have no purposes or values.
- If we have an immaterial soul that has certain normative
properties, then we have certain purposes and values.
- We do not have an immaterial soul that has certain
- We do not have certain purposes and values.
That is, the problem of explaining normativity is a real problem, but the
rejection of this or that specific explanation of normativity is not proof
that we cannot account for normativity with some other theory.