I believe it was Hume who made the point that reason cannot motivate us, only our feelings can. Supposing that's true, I have a far-flung conclusion that seems to follow from that: when the panelists on this site choose which questions to answer, they're motivated by some emotion, not by reason. But doesn't this corrupt the purity of the logic of the answer? Perhaps not necessarily so, but isn't it likely that of the 2,600+ questions a good number have been tainted? How is it not the case?

Hume's famous "motivation argument" does make the claim that reason -- at least on the traditional conception of this faculty, where its job is limited to making logical or causal inferences -- cannot motivate us to act. It would follow from this, as you rightly point out, that the panelists on this site must be motivated by passions when they choose which questions to answer. But it does not follow, however, that this must "corrupt the purity" of their answers. Let us distinguish between two roles that the emotions can have: (a) they can prompt us to answer a question, and (b) they can bias our answers. Hume does think that the emotions are capable of distorting our reasoning. Consider his famous claim about the development of our natural belief in gods and spirits. His argument is that our primitive ancestors would have arrived at this belief in order to satiate their fear and anxiety about their uncertain fates. This is a case of what philosophers refer to as "motivated irrationality". They...