The metaphysics of extension

Extension is a basic and immediately known reality. Bodies are extended, space has extension, time has length. We are familiar with the mathematical account of it. What about the metaphysical account?

Metaphysics analyses extension in light of the identity of the whole and the perfect (or act). Thus, extension has infinite imperfection, so far as by its very nature it admits of unlimited division. In natural extension, this division is not always infinite (though it remains infinite in motion and becoming) But there is nevertheless a necessity of division in all extension, and so a necessity of imperfection.

This imperfection is first overcome by that which, though extended, has its whole being in every division or part, that is, by life. In what lives, to exist is to live, and every part of that which lives is alive. Thus we divide mere extension from life, for the metaphysician knows life by its overcoming or transcendence of extension.

But if life transcends mere extension, there is nothing surprising in the fullest life transcending extension altogether. This fullest life is merely perfect and whole by itself, not existing in extended parts. Such subsistence is life, or that which transcends life. This is the existence of intelligence.

But extension serves as an analogue for other sorts of division that we find among intelligences. Just as we must transcend any division into extended parts, so too we must transcend the division of one intelligence from another. We attain to an intelligence that must be utterly sui generis, that is, of itself and in no way one of an enumerated plurality. This is the intelligence of the angel.


  1. RP said,

    December 1, 2010 at 3:28 am

    I recall reading somewhere that Aquinas says the universe as a whole has a form. Seems to make sense otherwise the universe would just be a heap of some kind. But if it does have a form (substantial form) then the problem with parts of it having their own substantial form – in effect two substantial forms (which Aquinas does not allow). So questions: Can a substantial form of a whole be an accidental form of its parts? Is quantity (extension, space) as a proper accidental form of composites due to the form of the universe as a whole? Of course, prime matter questions; “educing of form” from the dispositions of matter; and many more.

  2. December 1, 2010 at 4:38 am

    The universe is not a heap, nor does it have a substantial form, but it is still a whole by its order. The details of the order of the cosmos (the physical part of the universe) have changed a great deal since St. Thomas’s day, but the ontological hierarchies of both the universe and cosmos remain the same.

    • RP said,

      December 2, 2010 at 1:39 am

      but it is still a whole by its order.

      What, in your opinion, accounts for this order?

      Who makes the argument that the universe has no substantial form and where can I read it?

  3. Edward said,

    December 1, 2010 at 6:30 am

    Why can’t we say that any form, not just life, transcends extension? It seems as if extension is itself indifferent to any type of term since it is always infinite in motion and becoming. It is, in other words, indifferent to the unity that substances possess.

  4. December 1, 2010 at 8:20 am

    If — as I think to be the case — extension is created in the act of perception (i.e., it is a secondary, not primary quality), then extension is transcended just be being perceived, as the artist transcends his or her creations. Or to put it another way, without life there is no extension, so it is misleading to say that life transcends extension.

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