"Critic, n. A person who boasts himself hard to please because nobody tries to please him." (Ambrose Bierce, The Devil's Dictionary)
Among artists, the critic is often considered a necessary evil. Scholars, on the other hand, condescend to the critic at their peril. Indeed, scholarly writing presumes that there will be critics and that their opinions matter.
Nonetheless, the critic has been drawn into disrepute even within the academy. Critics, albeit sometimes more in the imagination of the writers they criticize than in reality, don't always know their place, and some scholars have therefore taken the view that critics should be avoided and ridiculed. That is, when someone expresses a critical opinion of a scholar's work, the scholar feels justified in dismissing the critique on the grounds that critics are, by their very nature, perversely interested in flaws, and writers in any case have a right to associate with more "positive" personalities who will be "supportive" and offer them "encouragement". While some critics do, of course, take things too far, I think it is more often true that the writer doesn't know how to take (and leave) criticism, than that the critic has no sense of his or her place. It takes two to be undermined by critique.
And it takes one to know one. So the best way of developing an understanding of the critic's function in scholarly life is to train one's own inner critic, to sharpen one's own critical edge. (A sharp knife, remember, is safer than a dull one.) Indeed, the first healthy or unhealthy relationship any writer develops to a critic, the most important healthy or unhealthy attitude a writer has about criticism, is that which is established in the writer's own case. Some writers never let their inner critic speak at all, and this shows in, well, very uncritical writing. But the more common problem is that the voice of the critic that the writer hears in his or her own head prevents the writer from writing. And this function of criticism—to prevent writing—is not healthy. Nor is it what the critic (if a proper critic) meant, or at least not what the critic is entitled to mean.
Criticism is supposed to prevent bad writing, but not by preventing writing altogether. That is why it is important to write down what one knows every day and then let the critic look at it only at particular times. Moreover, the critic's input needs to be absorbed in a constructive manner. That is, we must train ourselves to receive criticism, and we do this by regularly translating criticism into tasks that might improve the text. Absorbing the criticism is then a matter of completing those tasks ... one paragraph, 27 minutes, at a time. This gives the critic a robust, but limited object to criticize. You, the writer, knows how much you have put into it. And this gives the critic an important but limited task to complete: What could this paragraph get out of another 27-minutes of work?