In A Treatise of Human Nature, Hume says, "To form a clear idea of any thing, is an undeniable argument for its possibility, and is alone a refutation of any pretended demonstration against it." I think the modern way to put this is to say that conceivability is a guide to metaphysical possibility.

In Dialogues Concerning Natural Religion D9.6-7, Hume rejected that idea of necessary existence as meaningless. That seems to fit with his view that all knowledge comes from relations of ideas or matters of fact. But why shouldn't he also reject the idea of contingent existence as meaningless? It doesn't seem to be a relation of idea or matter of fact.

Am I missing something?

2 Answers 2


Contingent existence seems to have been a "matter of fact" for Hume. He supposed all "relations of ideas" to be knowable with certainty. Therefore contingent existence, to the extent that it is not known with certainty, must be a matter of fact.

It appears, therefore, that of these seven philosophical relations, there remain only four, which depending solely upon ideas, can be the objects of knowledge and certainty. These four are RESEMBLANCE, CONTRARIETY, DEGREES IN QUALITY, and PROPORTIONS IN QUANTITY OR NUMBER... (Treatise of Human Nature, "OF KNOWLEDGE")

The notion of contingent, external existence, Hume found to reflect certain "constancy and coherence" patterns within our perceptions.

Having found that the opinion of the continued existence of body depends on the COHERENCE, and CONSTANCY of certain impressions, I now proceed to examine after what manner these qualities give rise to so extraordinary an opinion... (Treatise of Human Nature, "OF SCEPTICISM WITH REGARD TO THE SENSES")


Should he reject all talk of modality? Should he reject talk of non-existents? If the answer to both of these questions is 'no,' then we have made ample space for why it would be worthwhile for Hume to take 'contingent existence' to be a serious concept, even if 'necessary existence' is rejected.

  • I was wondering if this is addressed by Hume and I missed it. I suspect that I'm missing something. Is this a relation of ideas or a matter of fact?
    – Kadav
    Commented Dec 28, 2016 at 16:54
  • @Kadav let me reread the section of Hume you're quoting and I'll get back to you Commented Dec 28, 2016 at 17:06

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