Earlier quoted context omitted.
The word you're looking for is academic. Carmack hasn't done academic work, but he has done plenty of scientific work. Scientific work is no less scientific if it isn't published in an academic journal. Academia doesn't hold a monopoly on the scientific method.
No, I mean scientific. What scientific work has Carmack done? I'm genuinely interested, because someone called him a scientist but I thought he was an engineer.
If not, does your definition of scientist require something other than doing work using the scientific method? Perhaps some specific quantity of work?
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[1] One of his companies, Armadillo Aerospace, was pretty much just a series of scientifc experiments. https://en.wikipedia.org/wiki/Armadillo_Aerospace