While preparing to write this post, I did a google search for “geometric method.” Many of the results of the search were about logic rather than about geometry as, for example, in Spinoza’s geometric method. In a way that makes sense, for Euclid’s geometry is famous for its use of self-evident axioms. However, that is not at all what I think of when I think about geometry and geometric method.

The way logic is used in geometry is very different from the way it is used in ordinary propositional logic. And that is what I mainly want to discuss here.

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