Key Arguments

• He notes that plants have soul and are physically affected by tangibles: 'And also why it is that plants do not perceive, although they have a part of soul, and are affected by tangible objects (for in fact they are cooled and heated).'
• He gives the reason: 'For the cause of this is their not having a mean, nor a starting-point of a sort | 424 b 1 | that can receive the forms of perceptible objects;'. Here he invokes his doctrine that sense-organs are means between contraries and possess a special kind of 'starting-point' (archê) suited to receive forms without matter.
• He contrasts plants’ way of being affected with perceptual affection: 'on the contrary, they are affected [by the form] along with the matter. 287' That is, plants undergo ordinary material alterations (being heated, cooled) where form and matter are not separated, whereas perception requires reception of form alone.
• By juxtaposing plant-affection and sense-perception, he sharpens the distinction between mere physical change and genuine perception: both involve being affected by external qualities, but only in the latter is there a formal reception into a suitable mean.

Source Quotes

285 It is evident from this why it is that excesses in perceptible objects destroy the perceptual organs (for if the movement is too strong for the perceptual organ, | 424 a 30 | the ratio is dissolved—and this, as we saw, is the perceptual capacity—just as the consonance and pitch [of a lyre] are if the strings are struck too forcefully). 286 And also why it is that plants do not perceive, although they have a part of soul, and are affected by tangible objects (for in fact they are cooled and heated). For the cause of this is their not having a mean, nor a starting-point of a sort | 424 b 1 | that can receive the forms of perceptible objects; on the contrary, they are affected [by the form] along with the matter.

286 And also why it is that plants do not perceive, although they have a part of soul, and are affected by tangible objects (for in fact they are cooled and heated). For the cause of this is their not having a mean, nor a starting-point of a sort | 424 b 1 | that can receive the forms of perceptible objects; on the contrary, they are affected [by the form] along with the matter. 287 But someone might raise a puzzle as to whether what is incapable of smelling can be affected in any way by odor, or what is incapable of seeing by color, and similarly in the other cases.

286 And also why it is that plants do not perceive, although they have a part of soul, and are affected by tangible objects (for in fact they are cooled and heated). For the cause of this is their not having a mean, nor a starting-point of a sort | 424 b 1 | that can receive the forms of perceptible objects; on the contrary, they are affected [by the form] along with the matter. 287 But someone might raise a puzzle as to whether what is incapable of smelling can be affected in any way by odor, or what is incapable of seeing by color, and similarly in the other cases. If, though, | 424 b 5 | the smellable is odor, then, if it produces anything, it is smelling that odor produces.

Key Concepts

• And also why it is that plants do not perceive, although they have a part of soul, and are affected by tangible objects (for in fact they are cooled and heated).
• For the cause of this is their not having a mean, nor a starting-point of a sort | 424 b 1 | that can receive the forms of perceptible objects;
• on the contrary, they are affected [by the form] along with the matter. 287

Context

II.12 (424a30–b3), where Aristotle applies his general account of perception as reception of form without matter to explain why plants, despite having soul and undergoing physical changes, lack perception.