The higher soul-capacities presuppose and contain the lower as potential, just as more complex geometrical figures contain simpler ones: the nutritive part is present potentially in the perceptual part, and in turn perception (especially touch) is a necessary condition for any other sense, while the nutritive and perceptual capacities can exist without the higher ones.

By Aristotle, from On the Soul

Key Arguments

  • He states the general structural principle: 'For the situation as regards the soul is quite similar to the one where the figures are concerned. For what is prior is always potentially present in what is next in order, both in the case of the figures and in the case of the animate things—for | 414 b 30 | example, the triangle in the quadrilateral, and the nutritive part in the perceptual one.'
  • He articulates a dependence relation between nutritive and perceptual powers: 'For without the nutritive part | 415 a 1 | there is no perceptual one, though the nutritive is separated from the perceptual one in the case of plants.'
  • He gives an analogous dependence among the senses: 'Again, without touch none of the other sorts of perception is present, but touch is present without the others.'
  • He supports this with empirical variety: 'For many animals have neither sight nor hearing | 415 a 5 | nor perception of odors.'
  • He later notes that among mortal beings, rational calculation presupposes all the lower capacities: 'For among the ones capable of passing away, those that have rational calculation also have all the rest, whereas of those that have each of the others, not all have rational calculation.'
  • This layered structure shows that higher capacities are built upon and include lower ones, while lower ones can exist independently.

Source Quotes

That is why it is ridiculous to inquire after a common account both | 414 b 25 | in these cases and in others, when it is an account that will not be special to any being, and will not accord with its proper indivisible species (eidos), to the neglect of the one that is of this sort. 178 For the situation as regards the soul is quite similar to the one where the figures are concerned. For what is prior is always potentially present in what is next in order, both in the case of the figures and in the case of the animate things—for | 414 b 30 | example, the triangle in the quadrilateral, and the nutritive part in the perceptual one.
178 For the situation as regards the soul is quite similar to the one where the figures are concerned. For what is prior is always potentially present in what is next in order, both in the case of the figures and in the case of the animate things—for | 414 b 30 | example, the triangle in the quadrilateral, and the nutritive part in the perceptual one. So we must inquire as regards each given case what the soul of each given one is—for example, what that of a plant is and that of a human or a beast.
And what the cause is due to which they have this order must be investigated. For without the nutritive part | 415 a 1 | there is no perceptual one, though the nutritive is separated from the perceptual one in the case of plants. Again, without touch none of the other sorts of perception is present, but touch is present without the others.
For without the nutritive part | 415 a 1 | there is no perceptual one, though the nutritive is separated from the perceptual one in the case of plants. Again, without touch none of the other sorts of perception is present, but touch is present without the others. 179 For many animals have neither sight nor hearing | 415 a 5 | nor perception of odors.
Again, without touch none of the other sorts of perception is present, but touch is present without the others. 179 For many animals have neither sight nor hearing | 415 a 5 | nor perception of odors. And of the ones that can perceive, some have the part capable of causing movement with respect to place, whereas others do not.
180 Finally, and most rarely, they have rational calculation and thought. 181 For among the ones capable of passing away, those that have rational calculation also have all the rest, whereas of those that have each of the others, not all have rational calculation, on the contrary, some | 415 a 10 | do not even have imagination, whereas others live by this alone. 182 And concerning the theoretical understanding a distinct account is required.

Key Concepts

  • For the situation as regards the soul is quite similar to the one where the figures are concerned.
  • For what is prior is always potentially present in what is next in order, both in the case of the figures and in the case of the animate things—for | 414 b 30 | example, the triangle in the quadrilateral, and the nutritive part in the perceptual one.
  • For without the nutritive part | 415 a 1 | there is no perceptual one, though the nutritive is separated from the perceptual one in the case of plants.
  • Again, without touch none of the other sorts of perception is present, but touch is present without the others.
  • For many animals have neither sight nor hearing | 415 a 5 | nor perception of odors.
  • For among the ones capable of passing away, those that have rational calculation also have all the rest, whereas of those that have each of the others, not all have rational calculation

Context

Mid-to-late II.3 (414b30–415a7, 415a9–10), where Aristotle draws the triangle–quadrilateral analogy to articulate the hierarchical inclusion of lower in higher soul-faculties and spells out the dependency relations between nutritive, perceptual, tactile, and rational capacities.