It doesn't matter if you try and try and try again, and fail. It does matter if you try and fail, and fail to try again.

Believe and act as if it were impossible to fail.

Problems are the price of progress. Don't bring me anything but trouble. Good news weakens me.

The world hates change, yet it is the only thing that has brought progress.

I think that the greatest education in the world is the education which helps one to be able to do the right things at the time it has to be done.

Great steps in human progress are made by things that don't work the way philosophy thought they should. If things always worked the way they should, you could write the history of the world from now on. But they don't, and it is those deviations from the normal that make human progress.

Modern psychology teaches that experience is not merely the best teacher, but the only possible teacher.. There is no war between theory and practice. The most valuable experience demands both, and the theory should supplement the practice and not precede it.