Aristotle's Psychology: On the Soul and Parva Naturalia

thought are embraced. These taken together form an ascending series in which the higher form always includes and presupposes the forms below it.¹

The function of nutrition furnishes the basis of sensation; sensation furnishes the basis of conceptual thought. The lower functions exist teleologically for the higher. Man, consequently, is the apex of creation, because all forms of life terminate in him as the complete development of what is contained implicitly and imperfectly in the lower organisms. These forms of life or soul, as we have enumerated them, are the following:

1. The nutritive or vegetal life.
2. Perceptive power or the life of sensation.
3. Creative power or desire attended by the capacity of local movement, sometimes called by Aristotle the kinetic soul.²
4. The life of intellect or reason, called the logistic reasoning or dianoëtic discursive/intellectual soul.

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These, as I have pointed out, are various manifestations of a unitary life. The soul is not divided into separate faculties or parts. In every organism it is a unit. In this respect Aristotle differs widely from Plato. The division of the soul into kinds is only a convenient abstraction. The soul’s powers are not topographically separable as in the Platonic psychology. The difference in kind is merely a difference in mode of operation and expression, determined by the nature of the materials with which the