“The nature of matter is that form cannot _persist_ in it, but it continually divests itself of one form and takes on another.” It is because of this property of matter that things come into being and cease to be, whereas form by its nature does not desire change, and ceases to be only “on account of its connection with matter.” Hence “_generic_ forms are all _constant_,” though they exist in _individuals which change_, which come and go; but _individual_ forms necessarily perish, since their existence is possible only in combination with finite matter.[94] “The soul of all flesh is its form,” and the body is the matter in which this form clothes itself. “When, therefore, the body, which is compounded of the elements, is dissolved, the soul perishes, because it exists only with the body” and has no permanent existence except _generically_, like other forms.[95] “The soul is one, but it has many different faculties,” and therefore philosophers speak of parts of the soul. “By this they do not mean that it is divisible as bodies are; they merely enumerate its different _faculties_.” The parts of the soul, in this sense, are five: the nutritive, the sensitive, the imaginative, the emotional, and the rational. The first four parts are common to man and to other animals, though “each kind of animal has a particular soul” special to itself, which functions in it in a particular way, so that, for instance, the emotion of a man is not like the emotion of an ass. But the essential superiority of the soul of man lies in its possession of the additional fifth part—the rational: this is “that power in man by which he thinks and acquires knowledge and distinguishes between wrong actions and right.”[96] Thus the soul of man differs from the souls of other living things only in the greater variety and higher quality of its functions. In essence it is, like “the soul of all flesh,” simply a form associated with matter, having no existence apart from the body. When the body is resolved into its elements the soul also perishes with all its parts, _including the rational_.