Friday, May 29, 2009

Substance

One of the fun games some ontologists like to play is to define substance. Here is one of my attempts. And now here comes another:

  1. x is a substance in the strong sense if and only if x is not dependent on anything
  2. x is a substance in the weak sense if and only if x is not non-causally dependent on anything.
Only God is a substance in the strong sense. It may seem that (2) does not describe a natural characteristic: it seems gerrymandered. I think that objection is compelling. It would help if one had a better account to put in of what non-causal dependence is like.

Notice that if the above definition is right, then an object that is dependent for its existence on its parts is not a substance even in the weak sense. One should be able to use this to argue for the Aristotelian axiom that no substance has parts that are substances.

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8 comments:

  1. Mike AlmeidaMay 29, 2009 at 12:20 PM

    Only God is a substance in the strong sense.It is hard to see, though, how abstract objects--maybe numbers, logically true propositions--depend for their existence on God. If God did not exist, there would be no logically true propositions? That's difficult to believe.

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  2. Alexander R PrussMay 29, 2009 at 4:18 PM

    If there are propositions, they are ideas in the mind of God.

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  3. DerrickMay 29, 2009 at 5:12 PM

    This comment has been removed by the author.

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  4. Mike AlmeidaMay 29, 2009 at 6:13 PM

    If there are propositions, they are ideas in the mind of God.Right, that's the standard answer, but I hadn't noticed (until I recently posted) that this commits you to the untenable position that there are no logically true propositions, if God does not exist. I don't want to fuss non-trivially true counterpossibles (though there are such, in my view), so the claim I am making is epistemic. But it seems epistemically mistaken, too. It is not an epistemic possiblity that (~p v p) is not true, but it is an epistemic possibility that God does not exist.

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  5. Alexander R PrussMay 29, 2009 at 6:22 PM

    It is epistemically possible that there are no propositions, and only sentences are bearers of truth. My understanding is that this is becoming the more common view among those who are working on truth, and the view that the truth of sentences is mediated by the truth of propositions is no longer the mainstream view.

    And it's not epistemically possible that there be no God, because the existence of God follows from self-evident truths. :-)

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  6. Mike AlmeidaMay 29, 2009 at 7:59 PM

    Alex,

    I didn't say that it's not epistemically possible that there are no propositions. Maybe it is, and maybe the truth-bearers are sentences (but I doubt it). I said that it's not epistemically possible that P v ~P is not true (whatever is the bearer of truth). But our main disagreement (and one that I'm sure can't be settled here) concerns the epistemic possibility that God does not exist. Since I take 'God' to be a directly referential term, it is perfectly possible that what you have in mind by God does not exist. The question is a posteriori, and hence it is epistemically possible that God (as you fix the reference of that term) does not exist.

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  7. Heath WhiteMay 30, 2009 at 11:52 AM

    What does 'anything' quantify over? I have this worry: let's say I am a rational animal. Then I am non-causally dependent on rationality and animality, since if these did not exist or were different then I would not exist or be different. So maybe you want to say, no we are not quantifying over properties but over substances. Then the definition offered is circular.

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  8. Alexander R PrussMay 30, 2009 at 1:05 PM

    Heath:

    That's a nice argument that if Platonism is true, then only the forms are substances.

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