Development Of The Human Soul

Appendix 16. (fn. 340).

The ancients, who were still without a formed philosophical language, expressed their thoughts about individuation (as about other difficult questions) in a rather confused way. They often confused individual with subsistent. Thus the Aristotelian affirmation that 'matter is the principle of individuation' meant, in their opinion, that matter made the individual subsist. But when they were discussing individuals lacking matter, they made an exception to their rule and said that in this case the form itself had to be subsistent. St. Thomas says: 'This kind of form, which is not acceptable in matter but is per se subsistent, is individuated by the very fact that it cannot be received in another' (S.T., I, q. 3, art 2. ad 3). Consequently they could not conceive how form could individuate and not be subsistent.

Again St. Thomas says, 'In these things which are not composed of matter and form and in which individuation is not present through individual matter, THE FORMS THEMSELVES MUST BE THE UNDERLYING SUBSISTENCES. Thus there is no difference in them between the underlying factor and nature' (S.T., I, q. 3, art. 3). The truth therefore is that 1. only form individuates; 2. form is either ideal or real. As ideal, it is known in the species which, although it individuates ideal being and is the principle of individuation (of a specific individual), does not multiply an ens, nor is it the principle of multiplication of individuals. As real, form is the principle of multiplication of individuals. Moreover, the forms of matter, which need matter in order to subsist, do not receive from matter their aptitude for individuating or for multiplying individuals. Finally, 3. they confused form with species or idea, just as they confused matter with subsistence. They said that pure form 'is the intellect in act' (St. Thomas, S.T., I, q. 66, art. 2), which is true however only of God, in whom the ideal form does not differ from the real form or subsistence, but not true of the angels, who are understood not through their subsistence but through an idea.