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I have an intuition that one can derive the principle of sufficient reason from the law of identity or non-contradiction but i don't know how. If someone knows I'd like some help.

  • No, one can not. Identity and non-contradiction are purely formal logical principles while sufficient reason is a substantive metaphysical claim. Any system of coherent brute facts validates all logical principles but PSR is false in it. – Conifold Sep 14 at 3:59
  • Which law of Identity? From whom? Hegel has different point of view on law of I dentity. ()The plant is the plant that it identifies different things. From this, it is easily inferred that statements like () are self contradictory, at least in the extended sense that they identify things that they require to be non-identical.jstor.org/stable/20128696?seq=1#metadata_info_tab_contents – Hassan Jolany Sep 15 at 9:04
  • Hegel draws precisely this conclusion about (*): we see that the beginning, 'The plant is?', sets out to say something, to bring forward a further determination. But since only the same thing is repeated, the opposite has happened, nothing has emerged. Such identical talk therefore contradicts itself.jstor.org/stable/20128696?seq=1#metadata_info_tab_contents – Hassan Jolany Sep 15 at 9:05
  • Hegel concludes also that the statement form 'A is A contradicts itself. This is easily inferred from the apparent incompatibility of the assertion for some A, that A is A, with the assumption that the two token singular terms replaced by the different occurrences of the letter 'A must be singular terms for two different things.jstor.org/stable/20128696?seq=1#metadata_info_tab_contents – Hassan Jolany Sep 15 at 9:07
  • Continued---....That, at any rate, is all the sense I can give to Hegel's celebrated claim, concerning the formula 'A is A, that The propositional form itself contradicts it: for a proposition always promises a distinction between subject and predicate, while the present one does not fulfil what its form requires jstor.org/stable/20128696?seq=1#metadata_info_tab_contents – Hassan Jolany Sep 15 at 9:08
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Maybe, but then only trivially.

One could argue that the Law of Identity is that for every A, A → A.

One could also argue that the Principle of Sufficient Reason is that for every B, there is an A such that A → B.

And then, for any given A, "For every B, there is an A such that A → B" reduces to "For every A, there is an A such that A → A". Which is true, if only trivially.

However, this also says that if you had to consider some fact in isolation, then it would have to be its own sufficient reason.

What we call facts are generally not isolated and so this doesn't apply to them. However, this applies to one fact we know is isolated by definition.

In this case, the Principle of Sufficient Reason requires that this fact be its own sufficient reason.

Then, if you accept the Principle of Sufficient Reason, you have to accept that a fact which is isolated by definition be its own sufficient reason.

And if you don't accept that a fact which is isolated by definition is its own sufficient reason, then you have to reject the Principle of Sufficient Reason.

This, assuming that there is at least one fact which is isolated by definition, which seems true, and assuming the twin interpretations of identity and sufficient reason given above, which we are all free to accept or reject.

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