The "castaways" on the first season of Survivor tried unsuccessfully to generate a fire using the fire plough (among other methods). It was clear from that, that some of them, at least, had read up on the subject, but apparently none of them had actually practiced it, so they couldn't get it to work when they needed to. <br>It was kind of a sobering lesson, that just reading the book and/or knowing the theory isn't enough.
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"The mind is not a vessel to be filled but a fire to be kindled."
-Plutarch