What I most admire about Euclid's ELEMENTS is that it proves everything, even the smallest assertion, holding nothing to be self-evident or not needful of proof. What appears to be so, may not be so ; so, prove it!
Indeed, the Bible says in the Old Testament, "Prove me now herewith ...," in Malachi 3:10.
Putting everything and everyone upon their proof, is good advice!
