Key Arguments

• He starts his approach by contrasting ensouled and non‑ensouled: 'We say, then, to make a start ... that what has soul is distinguished from what lacks soul by living.'
• He then analyzes 'living' as a disjunctive set of capacities: 'things are said to be living in many ways, and we say that a thing is alive if any one of these alone is present, for example, understanding, perception, movement and rest with respect to place, further the movement involved in nourishment, and also both withering and growth.'
• He explains why 'all plants too seem to be alive' by pointing to their intrinsic nutritive principle: 'For they evidently have within themselves a capacity and starting-point of this sort, through which they come to grow and decay in contrary directions. For they do not grow upward without growing downward, but grow in both directions alike, indeed in all directions, if they are constantly nourished and continue to live for as long as they are capable of taking nourishment.'
• He notes a crucial asymmetry: 'This can be separated from the others, but in the case of mortal beings the others cannot be separated from it. This is evident in the case of plants, since they have no other capacity of soul.' Thus nutrition can exist on its own, but higher powers depend on it.
• He characterizes animality by perception: 'It is due to this starting-point, then, that life belongs to living things, whereas being an animal is due primarily to perception. For even what does not move or change its place, but which does have perception, is said to be an animal and not just a living thing.'
• He singles out touch as the basic animal sense: 'Now the primary sort of perception that belongs to all animals is touch. And just as the nutritive can be separated from touch and every perceptual capacity, in the same way touch can be separated from the other perceptual capacities.'
• He summarizes the distribution: 'The nutritive, we say, is that part of the soul in which even plants share, whereas all animals evidently have the perceptual capacity of touch.'

Source Quotes

But such a definition is an account of the conclusion, whereas the one that states that squaring is the finding of the mean states the cause of the thing. 160 We say, then, to make a start | 413 a 20 | to the inquiry, that what has soul is distinguished from what lacks soul by living. But things are said to be living in many ways, and we say that a thing is alive if any one of these alone is present, for example, understanding, perception, movement and rest with respect to place, further the movement involved in nourishment, and also both withering and growth.

160 We say, then, to make a start | 413 a 20 | to the inquiry, that what has soul is distinguished from what lacks soul by living. But things are said to be living in many ways, and we say that a thing is alive if any one of these alone is present, for example, understanding, perception, movement and rest with respect to place, further the movement involved in nourishment, and also both withering and growth. That is why all plants too | 413 a 25 | seem to be alive.

But things are said to be living in many ways, and we say that a thing is alive if any one of these alone is present, for example, understanding, perception, movement and rest with respect to place, further the movement involved in nourishment, and also both withering and growth. That is why all plants too | 413 a 25 | seem to be alive. For they evidently have within themselves a capacity and starting-point of this sort, through which they come to grow and decay in contrary directions. For they do not grow upward without growing downward, but grow in both directions alike, indeed in all directions, if they are constantly nourished and continue to live for as long as they are capable of taking | 413 a 30 | nourishment.

For they do not grow upward without growing downward, but grow in both directions alike, indeed in all directions, if they are constantly nourished and continue to live for as long as they are capable of taking | 413 a 30 | nourishment. This can be separated from the others, but in the case of mortal beings the others cannot be separated from it. This is evident in the case of plants, since they have no other capacity of soul. It is due to this starting-point, then, that life belongs to | 413 b 1 | living things, whereas being an animal is due primarily to perception.

This is evident in the case of plants, since they have no other capacity of soul. It is due to this starting-point, then, that life belongs to | 413 b 1 | living things, whereas being an animal is due primarily to perception. For even what does not move or change its place, but which does have perception, is said to be an animal and not just a living thing.

It is due to this starting-point, then, that life belongs to | 413 b 1 | living things, whereas being an animal is due primarily to perception. For even what does not move or change its place, but which does have perception, is said to be an animal and not just a living thing. Now the primary sort of perception that belongs to all animals is touch.

For even what does not move or change its place, but which does have perception, is said to be an animal and not just a living thing. Now the primary sort of perception that belongs to all animals is touch. And just as the nutritive can be separated | 413 b 5 | from touch and every perceptual capacity, in the same way touch can be separated from the other perceptual capacities.

And just as the nutritive can be separated | 413 b 5 | from touch and every perceptual capacity, in the same way touch can be separated from the other perceptual capacities. 161 The nutritive, we say, is that part of the soul in which even plants share, whereas all animals evidently have the perceptual capacity of touch. The cause due to which each of these circumstances obtains, we shall state later.

Key Concepts

• We say, then, to make a start | 413 a 20 | to the inquiry, that what has soul is distinguished from what lacks soul by living.
• things are said to be living in many ways, and we say that a thing is alive if any one of these alone is present, for example, understanding, perception, movement and rest with respect to place, further the movement involved in nourishment, and also both withering and growth.
• That is why all plants too | 413 a 25 | seem to be alive. For they evidently have within themselves a capacity and starting-point of this sort, through which they come to grow and decay in contrary directions.
• This can be separated from the others, but in the case of mortal beings the others cannot be separated from it. This is evident in the case of plants, since they have no other capacity of soul.
• It is due to this starting-point, then, that life belongs to | 413 b 1 | living things, whereas being an animal is due primarily to perception.
• For even what does not move or change its place, but which does have perception, is said to be an animal and not just a living thing.
• Now the primary sort of perception that belongs to all animals is touch.
• The nutritive, we say, is that part of the soul in which even plants share, whereas all animals evidently have the perceptual capacity of touch.

Context

Central part of II.2 (413a20–b12), where Aristotle classifies life-functions, explains why plants count as living, and introduces perception—especially touch—as the defining feature of animals.