Hume (1711⁠–⁠76), who preceded Kant, accepting the usual view as to what makes knowledge a priori , discovered that, in many cases which had previously been supposed analytic, and notably in the case of cause and effect, the connection was really synthetic. Before Hume, rationalists at least had supposed that the effect could be logically deduced from the cause, if only we had sufficient knowledge. Hume argued⁠—correctly, as would now be generally admitted⁠—that this could not be done. Hence he inferred the far more doubtful proposition that nothing could be known a priori about the connection of cause and effect. Kant, who had been educated in the rationalist tradition, was much perturbed by Hume’s scepticism, and endeavoured to find an answer to it. He perceived that not only the connection of cause and effect, but all the propositions of arithmetic and geometry, are “synthetic,” i.e.