Key Arguments

• He observes that expressions like 'that by which we live' or 'that by which we perceive' are ambiguous, just as 'that by which we know scientifically' is: 'the [different sorts of] perception. For some animals have them all, others some, others only the one that is most necessary, namely, touch. But whereas something is said to be that by which we live or that by which we perceive in two ways, as is that by which we know scientifically (for in one way this is scientific knowledge, | 414 a 5 | in another it is the soul, since we say that we know scientifically by each of these)'.
• He brings in a parallel from health: 'and similarly we are healthy on the one hand by health and on the other by a part or even by the whole of the body,' indicating that there is both a formal condition (health) and a material bearer (the body).
• He characterizes scientific knowledge and health as formal, active conditions: 'and whereas of these scientific knowledge and health are shape and a sort of form or account, and as it were activity of the recipient, in the one case of what is receptive of scientific knowledge or receptive of health | 414 a 10 | (for the activity of those things that are capable of acting on something seems to occur in that which is affected and suitably disposed)'.
• He then applies this structure to soul: 'and since the soul is that by which we primarily live, perceive, and think, the result is that it will be an account and a form, and not matter and the underlying subject.' Thus soul is aligned with the formal/active side of the analogy, not with the bodily subject.

Source Quotes

For some animals have them all, others some, others only the one that is most necessary, namely, touch. But whereas something is said to be that by which we live or that by which we perceive in two ways, as is that by which we know scientifically (for in one way this is scientific knowledge, | 414 a 5 | in another it is the soul, since we say that we know scientifically by each of these), and similarly we are healthy on the one hand by health and on the other by a part or even by the whole of the body, and whereas of these scientific knowledge and health are shape and a sort of form or account, and as it were activity of the recipient, in the one case of what is receptive of scientific knowledge or receptive of health | 414 a 10 | (for the activity of those things that are capable of acting on something seems to occur in that which is affected and suitably disposed), and since the soul is that by which we primarily live, perceive, and think, the result is that it will be an account and a form, and not matter and the underlying subject. 168 For something is said to be a substance, as we mentioned, in three ways, as form, | 414 a 15 | as matter, and as what is composed of both.

Key Concepts

• But whereas something is said to be that by which we live or that by which we perceive in two ways, as is that by which we know scientifically (for in one way this is scientific knowledge, | 414 a 5 | in another it is the soul, since we say that we know scientifically by each of these),
• and similarly we are healthy on the one hand by health and on the other by a part or even by the whole of the body,
• and whereas of these scientific knowledge and health are shape and a sort of form or account, and as it were activity of the recipient, in the one case of what is receptive of scientific knowledge or receptive of health | 414 a 10 | (for the activity of those things that are capable of acting on something seems to occur in that which is affected and suitably disposed),
• and since the soul is that by which we primarily live, perceive, and think, the result is that it will be an account and a form, and not matter and the underlying subject.

Context

Transition section of II.2 (414a1–12), where Aristotle uses analogies with knowledge and health to clarify in what sense the soul is 'that by which' we live and to argue that soul is form and account rather than matter.