On The Soul   

different, as e.g. in the case of numbers and surfaces.

First, no doubt, it is necessary to determine in which of the

summa genera soul lies, what it is; is it 'a this-somewhat, 'a

substance, or is it a quale or a quantum, or some other of the

remaining kinds of predicates which we have distinguished? Further,

does soul belong to the class of potential existents, or is it not

rather an actuality? Our answer to this question is of the greatest

importance.

We must consider also whether soul is divisible or is without parts,

and whether it is everywhere homogeneous or not; and if not

homogeneous, whether its various forms are different specifically or

generically: up to the present time those who have discussed and

investigated soul seem to have confined themselves to the human

soul. We must be careful not to ignore the question whether soul can

be defined in a single unambiguous formula, as is the case with

animal, or whether we must not give a separate formula for each of it,

as we do for horse, dog, man, god (in the latter case the

'universal' animal-and so too every other 'common predicate'-being

treated either as nothing at all or as a later product). Further, if

what exists is not a plurality of souls, but a plurality of parts of

one soul, which ought we to investigate first, the whole soul or its

parts? (It is also a difficult problem to decide which of these

parts are in nature distinct from one another.) Again, which ought

we to investigate first, these parts or their functions, mind or

thinking, the faculty or the act of sensation, and so on? If the

investigation of the functions precedes that of the parts, the further

question suggests itself: ought we not before either to consider the

correlative objects, e.g. of sense or thought? It seems not only

useful for the discovery of the causes of the derived properties of

substances to be acquainted with the essential nature of those

substances (as in mathematics it is useful for the understanding of

the property of the equality of the interior angles of a triangle to