I've never taken an official online course for fun, but I read textbooks on my own all the time. Most of the science that I know has been self-taught. I have scads of science books on my shelf that I haven't gotten around to yet. A lot of my supplemental knowledge doesn't have a "degree" attached to it, so it's sort of hidden. This is also because a lot of my supplemental knowledge is information on mild special interest science topics that I find fascinating but have no interest in studying for an actual career (e.g., parasitology). But I've recently heard more about online certification courses and such that I might look into more in the future.
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Helinger: Now, what do you see, John?
Nash: Recognition...
Helinger: Well, try seeing accomplishment!
Nash: Is there a difference?