Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning. A person who never made a mistake never tried anything new. The world is a dangerous place to live; not because of the people who are evil, but because of the people who don’t do anything about it. We cannot solve our problems with the same thinking we used when we created them. Only a life lived for others is a life worthwhile. Great spirits have always encountered violent opposition from mediocre minds. If you can’t explain it simply, you don’t understand it well enough. You have to learn the rules of the game. And then you have to play better than anyone else. Education is what remains after one has forgotten what one has learned in school. Any man who reads too much and uses his own brain too little falls into lazy habits of thinking. Anyone who doesn’t take truth seriously in small matters cannot be trusted in large ones either. Insanity: doing the same thing over and over again and expecting different results.