One Argument for Matter as the Principle of Individuation

1.Material substances that are of the same species are numerically multiple.

2.This multiplicity must have its source in one of the general principles of material substances.

3.Since species is formal, this formality must then be multiplied either according to itself or according to something else.

4.If it is multiplied according to itself, then we would have distinct formalities by which something is made a member of a species.

5.To have distinct formalities, though, is to have different species. Different forms cannot constitute identical objects.

6.Therefore form cannot be the cause of numerical division in species.

7.The formality, then, must be multiplied according to something else.

8.We are left with matter, or the subject into which the substantial form is received.

9.Therefore matter is the principle by which members of the same species are individuated.


  1. Since you are using Scotist language, what do you think the difference between a form and a formality is? Or do you just mean the "formiess" of form? Can matter individuate over time? Most scientists and non Thomist scholastics would say that matter is in a state of flux and so cannot individuate anything.

  2. Let me begin by saying that I greatly enjoy your blog.

    From my sorely limited understanding of Scotus, the simplest account of formality I can give is that a formality is that which is distinguished by a formal distinction. I was not employing any type of formal distinction, however, so I suppose I was using 'formality' in the latter sense.

    In answering your other questions, I would first have to know what most scientists mean by matter. If they mean potency or, more specifically, the subject of change, which I doubt, then I still do not have to deny that material substances are never in a completely static state. Is saying that matter is in flux any different from saying that it possesses an essential indeterminacy? If not, then I do not see how this opposes the argument put forward in the post.