ABSTRACT: Can I be wrong about my own beliefs? More precisely: Can I falsely believe that I believe that p? I argue that the answer is negative. This runs against what many philosophers and psychologists have traditionally thought and still think. I use a rather new kind of argument, – one that is based on considerations about Moore’s paradox. It shows that if one believes that one believes that p then one believes that p – even though one can believe that p without believing that one believes that p.