The present argument explains where Logic comes from and why we have it.
P1. A=A. Identity is a fact insofar as everything that exists is itself.
P2. Because of the fact of identity A=A, A is determinate as itself and distinguishable from B, where A is not B. (An apple is itself, a star is itself, and thus an apple is not a star).
P3. This determination of what is identical to itself and distinct from what it is not is Logic, because it is the very function that is Logic and makes Logic what it is.
C. Therefore, Logic is grounded in the fact of identity: that what is, is itself, and is not what it is not.
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If formal logic tries to reject this argument, it must provide its own account of Logic; it must offer its own explanation for the ground of Logic (and if it arbitrarily rejects the burden of proof, then it cannot rightly demand it of others, or complain when others arbitrarily reject it).
Yet, any foundational justification formal logic offers will inevitably have to presuppose Logic, thus collapsing into circularity. (This claim can easily be falsified if the formal logician can provide a non-circular ground for Logic).
Crucially, the argument above does not ground Logic in Logic; it discovers it as being grounded in the existence of the universe, in the prior fact of determinacy (of identity) as the very condition that makes Logic possible (makes Logic what it is). (However, this knowledge is still only contained in and generated using Logic).
To use Logic to establish the ground of Logic is not the same as grounding Logic in Logic. We do not merely say, “Logic is what gave us Logic,” we recognize that Logic exists because of the determinate nature of the universe, which is a fact, not a concept of Logic. The Logical fact of the universe existed long before humans constructed any concepts of Logic, which is the only reason we can construct concepts in the first place. We can make and use determinate meaning only because the universe is mysteriously determinate, it has a Logical Nature not an illogical nature.
It doesn’t matter if one disagrees with the argument, the only thing that matters is whether one can actually refute it. And beyond that, what better explanation one can offer for their own position on the nature of Logic?