If we thing we are good enough, why would we become any better? So Chesterton says that tha man must doubt of his own capabilities, be modest about them...so in this way he will deliver his best, because he knows: what he intends to realize is not certain by his own capabilities...The man who thinks he is capable of everything, becomes useless, degenerate himself because he stop to try...he becomes demotivated, nut also, insecure...its a reflex of our time, when people start believing in things like "science is more important than philosopy or tradition" or "tradition ia not important at all"...these people deny the condition of existence of what they say they believe...I think it is something on this way