Accepting or succumbing to bullshit is foolish; rejecting bullshit is wise.
The proposition above is an example of an appraisal, a value judgment. And what field of learning studies appraisals? According to the late philosopher Curt Ducasse, the primitive or basic subject studied by philosophy is precisely various appraisals. And the knowledge of the norms of appraisals is wisdom. A philosopher, on this line of reasoning, is a lover of — in the sense of a searcher after — wisdom, which happens to be the etymological description of philosophy.
However, knowing what wisdom is, does not make one wise. The reason is quite straightforward. Wisdom consists of knowing how to act A in given circumstances C, which can be expressed by the conditional statement.
If one is in circumstance C, one should act (or do) A.
Now, it is possible to know this rule or norm, but not know that one is in circumstance C, or not to have a clear idea of the circumstance C. But the difficulty in acting wisely is further complicated by the phenomenon called “weakness of the will.” In other words, although you know how you should act, you do not. You may be lazy, you may procrastinate, you may be pulled by some other desire, with the result, you fail to act at all, or you fail to act in a timely manner. My point is, that wisdom is one thing, and acting wisely is another. Philosophy, according to Ducasse, studies the nature of wisdom; it does not make you wise. Put otherwise, the necessary condition for acting wisely, is having wisdom. But having wisdom is not a sufficient condition for being wise.
See: C. J. Ducasse, Philosophy as a Science: Its Matter and Its Method, 1941.