Friedrich Nietzsche was a provocative and complex thinker who wrote some of the most delightful books in the Western philosophical canon. But for our purposes, the best choice will be to concentrate on the central feature of his thought, which can be stated fairly simply.

Western culture for quite a long time—for at least two millennia—has operated out of a delusion. We have believed that our minds, which are phenomena of this world, can somehow be brought into contact with realms and forces not of this world which inform us that what we commonly call reality is, in truth, neither real nor good and therefore that we should be devoting our lives to escaping it.

This, according to Nietzsche, is a pathological illogic. If the world is not real, then our minds, which are parts of the world, are not real either. And to pay attention to unreal minds is an absurdity.

The way out of this delusionary illogic lies in facing the truth that this is the only world we have and, in fact, that this is the only world which exists. With the truth of the world's reality in mind, we might then adopt perspectives that would allow us to live healthily within it. We probably cannot exaggerate the degree to which health was for Nietzsche the single intelligent goal of living. As he says in Ecce Homo: ‘I turned my will to health into a philosophy’.