The most visible example of this is the rumpus surrounding the famous passage in which Hume declares that reason by itself is inert, and has no other office than to serve and obey the passions. The mountains of commentary this has excited include accusations that Hume is a skeptic about practical reasoning (whatever that might mean); that he is a nihilist who cannot have any values; that in his eyes nothing matters; that he is too stupid to realize that learning that a glass contains benzene instead of gin might extinguish your desire to drink from it; that he constantly forgets his own theory; and indeed, in the words of one contemporary writer — the frothing and foaming and insolence here reach a crescendo — that philosophers like Hume only avoid being “radically defective specimens of humanity” by constantly forgetting and then contradicting their own views.The contemporary writer in question is Allen Wood. Here Blackburn quotes Wood at greater length, writing that, as Wood sees it:
Humeans must say that there are no reasons for anything—nothing matters. They are rank nihilists! Nicely illustrating how to combine poverty of imagination with vulgarity of tone, one of the commentators included here, Allen Wood, describes them as ‘either radically defective specimens of humanity who are incapable of feeling respect for anyone or anything, or else every time they do feel it they commit themselves to contradicting their own metaethical theories’. Golly.It seems to me that Wood is saying that the Humean theory would only be true if people were much worse than they actually are. Whether that's true or false, I don't think that saying it is so vulgar, insolent, frothing, or foaming.
Reasons are tricky things because they can be thought of as motives or as justifications. Hume's claim that reason is the slave of the passions covers both these ideas: reason does not move us to action without some accompanying emotion, and reason ought not to move us unless in the service of some (presumably good) emotion, according to him. The 'ought' that follows the 'is' (in "Reason is, and ought only to be, the slave of the passions") is a little odd, but not disastrously so. If reason cannot be anything else then why say that it ought not to be anything else? If it could be something else then how can Hume be so sure that it isn't? I assume he means that it isn't and we shouldn't pretend, or try to act, otherwise.
It depends what you mean by 'reason' though, surely. Hume seems to mean something like 'the calculative faculty,' and I suppose that is a slave of the passions. But if by 'reason' we mean something closer to sanity, then reason is not such a slave. It isn't rational in that sense of 'reason' to prefer the destruction of the world to the scratching of one's finger.
Schopenhauer says that all actions are the result of the agent's character combined with a motive, where I think the motive is taken to be something like a carrot and a relevant feature of one's character might be loving carrots. The carrot alone does not cause my movement towards it, but then neither does reference to my love of carrots unless we know (that I believe) there is a carrot there. This picture seems all right as far as it goes, but it seems to rely on the fact/value distinction perhaps a little too much. If I avoid pain do we need to add that my character happens to have aversion to pain as one of its features? Or if I do the right thing do we need to add that I happen to be the kind of person who values rightness in order to make sense of my behavior?
It's tempting to say that we only don't need to because it goes without saying. But I wonder. Can we really understand something's being painful without understanding it as to-be-avoided? Or something's being right without understanding it as desirable? If something is desirable other things being equal, we don't need to add "and other things are equal in this case." It is analytic that the painful is to be avoided (other things being equal) and the right (if there is such a thing) is to be done, isn't it? Which I suppose is just a way of saying that some concepts are normatively loaded. "Because there were carrots in it" is not an intelligible reason for running into a burning building, unless I know that the runner really loves carrots. But "Because my daughter was in it" is a perfectly intelligible reason. And not because we add an unspoken "And people love their daughters."
If, as Blackburn says, "reasons have become the Holy Grail of contemporary philosophy," then it seems that philosophers would do well to pay more attention to grammar, to the definition and use of words like 'reason'. But I suppose I would say that.
[UPDATE: when I first conceived this post I thought I had something to say. Now I'm less sure that that's the case, especially given how vast the literature on this subject is and how little I even try to say about it here. But my sense is that a lot of time has been spent arguing about what reasons really are and whether reason is really the slave of the passions, and so on. If the answer to these questions is "It depends what you mean by 'reason'," or "In this sense/these cases Yes, but in that sense/those cases No," then much of this energy might have been wasted.]