I know that many students feel at times like they aren’t capable of doing what they need to do to ace their classes, to graduate, to move on into the “real world” or higher up in academia. Sometimes they feel like they are just “faking” being smart, and that someone will catch them at it.
This is known as “impostor syndrome” and is quite common—Wikipedia even has a page explaining it. People from underprivileged backgrounds or who have been socialized to think of themselves as somehow inferior suffer from it more than those who have been taught to be confident in what they do. For example, women in physical and computational sciences often doubt themselves, even when the objective evidence is that they are quite capable.
Even tenured professors, who have passed through many tests of their resolve and ability, often suffer from impostor syndrome. I suggest the following reading (all from a single author) for those who are wrestling with this problem (the author selected these posts herself from her larger body of work):
Maria Klawe, president of Harvey Mudd College, has a good, short article on her own experiences with impostor syndrome in Slate. For a somewhat younger perspective, Alicia Liu’s article Overcoming Imposter Syndrome is worth reading.
Incidentally, there is a flip side to the problem, of students (often, but not exclusively, male students from privileged backgrounds) having too much confidence and not being aware when they are out of their depth, failing to ask for help when they need it.
Both problems can be tackled with the same approach: seeking outside verification of your abilities and paying attention to the feedback. This is easiest while being a student, as there are many formal mechanisms in place for honest feedback—it gets harder when you have to rely on the more random mechanisms of journal paper reviews and grant proposals or pats on the back from co-workers.
As a community, we can all help with both problems by providing honest feedback (neither ego strokes nor unwarranted criticism) when asked for it, and by asking for feedback ourselves.
For my part, I tend to see the negative both in my own work and in others’ work, and I am working on trying to increase the amount of positive feedback I give people.