Doing something professionally just means doing it for money and with the authorization of others, not necessarily doing it well. We all know about professional software developers who are forced by their profession, that is, the fact that they do it under contract X for company Y managed by person Z, to do things that they know are complete crap. I mean, SAP is professional. Microsoft or Google lock-in? Highly professional! Shiny even. Supporting RSS? Not professional. A gimmick you're allowed, like what you do outside of work. Or even more brutal: Ignaz Semmelweis. That he was a professional didn't help him, the super mega cereal professionals undid his efforts without blinking, and without anyone even realizing it at the time.

At the same time, people just make stuff up without any rigor, just take climate change denial and whatnot. So it's not that not being a professional is any positive indicator, either. I just think that if you do something others don't already do, they cannot authorize you, by definition. They don't know what they're even talking about, while thinking they do. Not their fault, not your fault, but if you don't do you, "you" will not be done, and the world will never know.

Of course, in the end the results have to hold up, my point is not to give license to "questioning everything" as code for just spouting non-sequiturs. But I wouldn't dissuade "randoms" from pursuing scientific fancies because the professionals got it, because frankly, they don't. No single person or group or class does.

The main point of the essay is that it takes all sorts, and that you shouldn't put your eggs into one basket. IMO "professionals" is one single basket, the way everybody and their dog is streamlined and appropriate these days.

last but not least:

> However these 3 years of work in isolation, when I was thrown onto my own resources, following guidelines which I myself had spontaneously invented, instilled in me a strong degree of confidence, unassuming yet enduring, in my ability to do mathematics, which owes nothing to any consensus or to the fashions which pass as law.

[..]

> By this I mean to say: to reach out in my own way to the things I wished to learn, rather than relying on the notions of the consensus, overt or tacit, coming from a more or less extended clan of which I found myself a member, or which for any other reason laid claim to be taken as an authority. This silent consensus had informed me, both at the lyé and at the university, that one shouldn't bother worrying about what was really meant when using a term like "volume", which was "obviously self-evident", "generally known", "unproblematic", etc. I'd gone over their heads, almost as a matter of course, even as Lesbesgue himself had, several decades before, gone over their heads. It is in this gesture of "going beyond", to be something in oneself rather than the pawn of a consensus, the refusal to stay within a rigid circle that others have drawn around one - it is in this solitary act that one finds true creativity. All other things follow as a matter of course.

-- Alexandre Grothendieck, "The Life of a Mathematician - Reflections and Bearing Witness" (1986)

edit: something I just stumbled across, same point: https://www.youtube.com/watch?v=PbmJkMhmrVI&t=41m14s