The same mediated structure of causation applies to hearing and smell (and in a different way to touch and taste): the sensible object moves an intermediate medium (air for sound, a nameless affection common to air and water for odor), which then moves the corresponding sense organ; placing the sounding or odorous object directly on the organ yields no perception.

By Aristotle, from On the Soul

Key Arguments

  • He explicitly generalizes his account of vision: 'The same account applies to both sound and odor. | 419 a 25 | For none of these produces perception when it touches the perceptual organ.'
  • He repeats the mediated-causation structure: 'Instead, due to odor and sound, what is intermediate is moved, and, due to this, each of the perceptual organs.'
  • He notes the empirical point that direct contact does not yield perception in these modalities: 'And when we place what makes a sound or has an odor on the perceptual organ, it produces no perception whatsoever.'
  • He adds that something similar holds even for touch and taste, though it is less obvious and will be explained later: '(The same applies to touch and taste, | 419 a 30 | though it does not appear to. The cause of this will be clear later. 242)'
  • He identifies the specific media: 'The medium for sounds is air and for smell something nameless.'
  • He characterizes the olfactory medium as an affection common to air and water, with an analogy to the transparent for color: 'For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor.'
  • He points to zoological evidence: 'For even aquatic animals | 419 a 35 | appear to have a perception of odor.'

Source Quotes

For it is due to this that the transparent becomes transparent. The same account applies to both sound and odor. | 419 a 25 | For none of these produces perception when it touches the perceptual organ. Instead, due to odor and sound, what is intermediate is moved, and, due to this, each of the perceptual organs.
The same account applies to both sound and odor. | 419 a 25 | For none of these produces perception when it touches the perceptual organ. Instead, due to odor and sound, what is intermediate is moved, and, due to this, each of the perceptual organs. And when we place what makes a sound or has an odor on the perceptual organ, it produces no perception whatsoever.
Instead, due to odor and sound, what is intermediate is moved, and, due to this, each of the perceptual organs. And when we place what makes a sound or has an odor on the perceptual organ, it produces no perception whatsoever. (The same applies to touch and taste, | 419 a 30 | though it does not appear to.
And when we place what makes a sound or has an odor on the perceptual organ, it produces no perception whatsoever. (The same applies to touch and taste, | 419 a 30 | though it does not appear to. The cause of this will be clear later. 242) The medium for sounds is air and for smell something nameless. For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor.
The cause of this will be clear later. 242) The medium for sounds is air and for smell something nameless. For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor.
242) The medium for sounds is air and for smell something nameless. For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor. For even aquatic animals | 419 a 35 | appear to have a perception of odor.
For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor. For even aquatic animals | 419 a 35 | appear to have a perception of odor. But the human {35} beings, and footed animals | 419 b 1 | that breathe, cannot smell without breathing.

Key Concepts

  • The same account applies to both sound and odor. | 419 a 25 | For none of these produces perception when it touches the perceptual organ.
  • Instead, due to odor and sound, what is intermediate is moved, and, due to this, each of the perceptual organs.
  • And when we place what makes a sound or has an odor on the perceptual organ, it produces no perception whatsoever.
  • (The same applies to touch and taste, | 419 a 30 | though it does not appear to. The cause of this will be clear later. 242)
  • The medium for sounds is air and for smell something nameless.
  • For there is an affection common to air and water, and as the transparent is to color so this affection, which belongs to both of these, is to what has odor.
  • For even aquatic animals | 419 a 35 | appear to have a perception of odor.

Context

Later part of II.7 (419a23–35), where Aristotle extends his mediational model of perception from sight to hearing, smell, and prospectively touch and taste, and specifies the relevant media.