A number of good ideas touched on in this talk. It primarily focuses on how the good concepts are those that are hard to vary, which is more instructive than the usual "prefer simplicity" (but not in the amount of stuff suggested by the theory, not in the diversity of its real-world implications, et cetera, et cetera). It reminds of how the roots of any knowledge necessarily lie in human mind. It makes a welcome emphasis on how the scientific revolution, a mere methodological change, ended a stasis tens of thousands of years long, and hence the importance of understanding this change.