I mean, there’s definitely a date in the past before which this definition is not useful. On the other hand, if a human learns something new, but nobody else does as a consequence of that, has human knowledge advanced? There are always edge cases—occasionally the mere awareness that something is possible has allowed others to rediscover the method—but generally I’d say no.

That does not mean that dissemination of new information has to work like it does now. The Republic of Letters was very different but quite successful. But if you have taken no effort to make your discovery available to others, I’d say you’re not advancing the cause of human learning; if you have taken effort to ensure it is not available, like what many patents aim for nowadays, I’d say you’re working against it.

The folks doing experiments on telescopes, astronomy, etc., during Medieval Europe, almost always made great efforts to publicize their work.

On the other hand, those who at the same time were experts in, for instance, making shoes, made efforts to keep secret their techniques.