-- what could be more essential for a philosopher, if a philosopher truly is a lover of wisdom? If you never admit that you may be wrong, you'll never know more than you do now, you'll just know less and less as you forget stuff.
And yet this willingness seems so often to be lacking among those who consider themselves to be philosophers. Look at them debating: Philosopher1 asserts: A. Philosopher2 says: no, you're wrong, B. Philosopher1 retorts: B!? You're obviously unfamiliar with Philosopher3's work on this topic, you dolt! Educate yourself before you dare to darken my door! Philosopher3 pops up and says: You're both idiots! C!
And this unfortunate behavior occurs not only when questions of a deep and universal nature are being discussed, questions which an objective onlooking Philosopher4, if such could be found, might well consider to be unanswered or possibly even unanswerable. Philosophers can be found behaving this way concerning questions of a much more mundane nature such as "Was Philosopher5 an atheist?"
You might be thinking to yourself: "How could you fuck up a question as mundane as that? All you have to do is examine the statements of Philosopher5, and conclude from them that Philosopher5 was either a believer, or an atheist, or an agnostic, or that he (Let's face it: to the greater glory of neither philosophy nor the male gender, most philosophers have been and continue to be male.) changed his position on this matter from time to time, or that the evidence is insufficient to answer the question."
That's a perfectly sensible thing to think, but if you're thinking that, you may be far too sensible to be a philosopher, or at least, to be a run-of-the-mill philosopher. For, unfortunate and illogical as it seems, Philosophers1, 2, 3 & 4 may actually leave the late and highly-esteemed Philosopher5 out of the discussion entirely, and instead quote Philosophers6, 7, 8 & 9 on the matter as if they know things about Philosopher5 which Philosopher5 himself did not.
Looking at them bickering, you might get the impression that neither Philosopher1 nor 2, 3 or 4 actually cares about Philosopher5 as much as winning a game whose rules are petty, shameful and never openly acknowledged and whose stakes have to do much less with wisdom than with tenure and who gets which office or the front-cover headline in JournalX. And sadly, your impression might be entirely correct. (You might think that I'm exaggerating things -- but only if you've never had very much contact with philosophers.)
Not that so much as a Bachelor's degree is required in order to engage in this sort of a travesty of non-debate. All that is essential is an unwillingness to admit the possibility of error, instead of, when you say A and someone responds: B, asking that person for his or her evidence for B, and actually being glad if in the course of the discussion you learn something. If you're that kind of person, and you're also a philosopher, it may just be that you have a big leg up on other philosophers, and it may even be that you're the kind of philosopher who, long after you're dead, other philosophers may pretend to be arguing about, when they're actually bickering over disgusting things which have nothing to do with you, and dragging your good name down to their revolting level.