I have been reading John Amos Comenius’ Orbis Sensualium Pictus, and I came upon a usage of ‘vel’ and ‘aut’ that I do not completely understand: “Oculus videt colores, quid album vel atrum, viride vel caeruleum, rubrum aut luteum, sit.” (“The eye seeth colours, what is white or black, green or blew, red or yellow.”) So why does Comenius switch to ‘aut’ for the last pair of colors? Is there some definitive grammatical reason for this? Thanks.
In Classical Latin the distinction seems to be one along inclusive/exclusive lines. e.g potes habere aut pacem aut bellum “you can have either peace or war [but not both]”; vel is inclusive and much weaker e.g Caesar vel Augustus nominatur “he is called Caesar or Augustus [does it matter which?]”.
It is a distinction unlikely to be found in much Neo-Latin. It may help to simply think of aut as stronger.
quid album vel atrum,
viride vel cœruleum,
rubrum aut luteum, sit.
There’s a sort of poetic swing to these lines, and ‘vel luteum’ would be awkward. Scribo tells us that the aut/vel distinction had been lost, and Latin was very much a living language for educated fellows, right up to the 1800s.
Haha, I’d been reading Orbis Sensualium Pictus, too, and had been wondering the exact same thing! Thank you for asking this question, jkpoff. And thank you, Scribo and johnwheater for these illuminating answers, from two different perspectives!