Origins: Quod Erat Demonstrandum

When did people begin to think logically? There is no answer to this question. Rationality of some kind existed before even the earliest stone tools, since such objects must have been produced in the rational expectation that they would make certain tasks easier. As far back as we can imagine, human beings behaved rationally (which is not to say that they haven’t also behaved irrationally): It has always been “logical” to suppose that the sun would indeed rise again, that a rock thrown upward would fall to the ground, and that briny seawater would not make a very healthy […]