I aim to show that constructive realism is superior to alternative theories of knowledge and reality offered by different variants of skepticism, empiricism, and idealism. Skepticism is the view that we have no knowledge at all, so that any talk of the nature of reality is pointless. Some ancient Greek philosophers advocated an extreme form of skepticism according to which neither sensation nor opinion could give us any grounds for separating truth from falsehood. An influential current form of skepticism is found in postmodernist philosophers and literary theorists who view the world as a text open to many kinds of interpretations, none of them demonstrably better than the others. In fields such as history, anthropology, and cultural studies, it has become fashionable to claim that reality is just a social construction, so that the idea of objective knowledge is only a myth. I will try to show how objectivity is possible through the complex perceptual and theoretical abilities of our brains. Brains are not mirrors of nature, but they are powerful instruments for representing it.