Progress is Providence without God. That is, it is a theory that everything has always perpetually gone right by accident. It is a sort of atheistic optimism, based on an everlasting coincidence far more miraculous than a miracle.
There is an optimism which nobly anticipates the eventual triumph of great moral laws, and there is an optimism which cheerfully tolerates unworthiness.
An optimist will tell you the glass is half-full; the pessimist, half-empty; and the engineer will tell you the glass is twice the size it needs to be.