Socrates and Aristotle both say that we desire what is (or what we perceive to be) good. Spinoza and Nietzsche both believe that we call good what is it that we (already) desire. Who is right?
David Wiggins suggests that we do not have to choose. Parsing Aristotle, he writes, ‘The good is the sort of thing we wish for because we think it good, not something we think good because it is what we wish for’ (‘Deliberation and Practical Reason,’ 231). In the endnote, he helpfully remarks,
It is the beginning of philosophical wisdom on this matter, both as an issue of interpretation and as a philosophical issue, to see that we do not have to choose between Aristotle’s proposition [‘We desire it because it is good for us’] and its apparent opposite [Spinoza’s]. We can desire it because it seems good and it seems good because we desire it. (239)
I believe for any rationalist that the first is easier to see than the second (which appears unapologetically voluntarist). I may desire love because it seems good to me, but why it also true that love seems good to me because I desire it? Could I not be in error?
The reply could be that practical reason and desire are not two analytically distinct faculties (it is question-begging to believe that they have to be) but two related activities that accompany each other in the context of action. Practical reason helps me to see what object (say) is worthy of my love, and, concomitantly, volition allows me to want this woman. Perceiving that this woman is worthy of my love can be in concert with desiring her, here and now. A caress would say as much.
Postscript.–Perhaps the perceived choice between rationalism and voluntarism is the fall-out of a certain misunderstanding. The truth is that virtue attracts, vice detracts. In Pride and Prejudice, Elizabeth initially desires Wickham because she believes him to be good; she believes him to be honest, agreeable, well-bred, amiable, and so forth. But when she learns otherwise, she no longer perceives him as good and at the same time she no longer desires him. Withdrawing the claim to goodness also withdraws the pull of desire; and noticing that she does not desire him is the starting point for her search for reasons.