Necessity is the mother of all invention.

If the facts don't fit the theory, change the facts.

Everything that is really great and inspiring is created by the individual who can labor in freedom.

My only refuge, as a serious young man, from the despair of my financial burden to my family, is that I did everything I could to never permit myself any amusements or diversions except those afforded by my studies.

The stupid are invincible.

Enjoying the joys of others and suffering with them-these are the best guides for man.

We cannot solve our problems with the same thinking we used when we created them.