I think the Aristotelian (though I might have reached for Platonic) idea is that there is an "A" which is essential, and that you map many various "A"s to that one A - which results in weirdness when you leave the Latin-alphabet based languages.
(Arguably even in English we run into the fact that there is not one "A" - there are many "A"s that sound and act completely different, and we collapsed them into one representation.)