ABSTRACT
The object of psychology is ‘to discover the nature and essence of soul, and its attributes.” The method of dealing with the attributes is demonstration; is there, Aristotle asks, a corresponding method of discovering the essence? He suggests division as a possible method, and in effect adopts it. The first step is to determine to which of the main divisions of being - the categories - soul belongs, and again whether it is a potentiality or an actuality. But at this point a difficulty arises. Suppose that there are different parts of soul, and various species or perhaps even genera arising from the presence of these parts in various combinations; it may then be that there is no one definition of soul. It may be that the primary facts are the different kinds of soul, and that there is no one thing answering to the name ‘soul’ in general, or only a slight nucleus of common nature in the various SOU~S.~
Aristotle’s answer is in effect that the kinds of soul are neither so much alike that any single definition of soul will give a sufficient idea of its varieties, ranging from its humble manifestations in plants and zoophytes to the heights it reaches in man or in God, nor yet so different that we cannot recognise a common nature in all its varieties. Geometrical figures may be arranged in an order beginning with the triangle and proceeding to more and more complex forms, each of which contains potentially all that precede. So too the forms of soul form a series with a definite order, such that each kind of soul presupposes all that come before it in this order, without being implied by them. The minimal soul is the nutritive; for this exists in all living or ‘besouled’ beings - in plants and animals alike. Next comes the sensitive soul, which exists in all animals. Within the sensitive soul
the same scheme reappears, for touch is a minimal form of sensation pre-supposed by all the others, present whenever they are and sometimes when they are not.3 And it is perhaps not too fanciful to say that for Aristotle touch, taste, smell, hearing, sight form a series in which the distinctive nature of sensation, that of ‘receiving the form without the matter’ of its objects, is increasingly manifested.4
