"I’m going to discuss how we would look for a new law.
In general we look for a new law by the following process:
First: We guess it. (Met by laughter from the audience). Don’t laugh, that’s really true.
Then: We compute the consequences of the guess, to see if the guess is right, what it would imply
And then: We compare the computation results to nature … or we say compare to experiment or experience. Compare it directly to observation to see if it works.
If it disagrees with experiment, it's wrong. In that simple statement is the key to science. It doesn't make any difference how beautiful your guess is. It doesn't make any difference how smart you are, who made the guess, or what his name is. If it disagrees with experiment, it's wrong."