Matter and quiddity

One of the bedrocks of St. Thomas’s account of knowledge is his distinction between common and “signate” or “individual” matter:

Some have thought that the species of a natural thing is a form only, and that matter is not part of the species. If that were so, matter would not enter into the definition of natural things. Therefore it must be said otherwise, that matter is twofold, common, and “signate” or individual; common, such as flesh and bone; and individual, as this flesh and these bones. The intellect therefore abstracts the species of a natural thing from the individual sensible matter, but not from the common sensible matter; for example, it abstracts the species of man from “this flesh and these bones,” which do not belong to the species as such, but to the individual (Metaph. vii, Did. vi, 10), and need not be considered in the species: whereas the species of man cannot be abstracted by the intellect form “flesh and bones.”

The foundation of this distinction is that matter both enters into what something is, and distinguishes it from what it is. In considering the thing, the intellect considers matter in the first way and not in the second. Still, it is the same matter that is both! There is not a real distinction between common and signate matter But how can one and the same principle be both essential to a quiddity and yet distinct from it? The problem leads us to say that matter, by entering into quiddity, is properly that-by-which something fails to be a quiddity. When we say that the intellect knows the quiddity of material things we are saying that it knows something that cannot be fully verified or exemplified in the things it knows.

1 Comment

  1. September 9, 2008 at 4:11 pm

    Every human being must have a body or personality (signate matter), but it need not be this body or this personality (individual matter). When we consider one’s kind-essence, we must attribute to it a body in the abstract; when we consider one’s individual-essence, what that particular person is or rather who he is, we consider his body in the concrete.

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