Or so the saying goes. It is a popular maxim that has been around for some time, and has maintained an almost universal popularity. But G.K. Chesterton, some years ago, gave a powerful critique of it. In his book, Orthodoxy, he writes this. It is worth mentioning that these words were published in 1908, well before the decades and decades of "believe in yourself" mantra in the U.S.
Thoroughly worldly people never understand even the world; they rely altogether on a few cynical maxims which are not true. Once I remember walking with a prosperous publisher, who made a remark which I had often heard before; it is, indeed, almost a motto of the modern world. Yet I had heard it once too often, and I saw suddenly that there was nothing in it. The publisher said of somebody, "That man will get on; he believes in himself." And I remember that as I lifted my head to listen, my eye caught an omnibus on which was written "Hanwell." I said to him, "Shall I tell you where the men are who believe most in themselves? For I can tell you. I know of men who believe in themselves more colossally than Napoleon or Caesar. I know where flames the fixed star of certainty and success. I can guide you to the thrones of the Super-men. The men who really believe in themselves are all in lunatic asylums."