Our observation of nature must be diligent, our reflection profound, and our experiments exact. We rarely see these three means combined; and for this reason, creative geniuses are not common.

There are three principal means of acquiring knowledge... observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination.

There are three principal means of acquiring knowledge. . . observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination.

It is not human nature we should accuse but the despicable conventions that pervert it.

There are things I can't force. I must adjust. There are times when the greatest change needed is a change of my viewpoint.

No man has received from nature the right to command his fellow human beings.