Adversity is the mother of progress.

There is a subtle danger in a man thinking that he is "fixed" for life. It indicates that the next jolt of the wheel of progress is going to fling him off.

I invented nothing new. I simply assembled the discoveries of other men behind whom were centuries of work. Had I worked fifty or ten or even five years before, I would have failed. So it is with every new thing. Progress happens when all the factors that make for it are ready, and then it is inevitable. To teach that a comparatively few men are responsible for the greatest forward steps of mankind is the worst sort of nonsense.

To follow the path that others have laid before you is a reasonable course of action; therefore all progress is made by unreasonable men.

Without death there would be very little progress.

Take any path you like; follow any prophet you like; but have only that method which suits your own nature, so that you will be sure to progress.