Man is an animal which, alone among the animals, refuses to be satisfied by the fulfillment of animal desires.

When one door closes, another one opens.

Great discoveries and improvements invariably involve the cooperation of many minds. I may be given credit for having blazed the trail, but when I look at the subsequent developments I feel the credit is due to others rather than to myself.

The inventor is a man who looks around upon the world and is not contented with things as they are. He wants to improve whatever he sees, he wants to benefit the world; he is haunted by an idea. The spirit of invention possesses him, seeking materialization.

Don't keep forever on the public road, going only where others have gone. Leave the beaten track occasionally and dive into the woods. You will be certain to find something you have never seen before. Of course it will be a little thing, but do not ignore it. One discovery will lead to another, and before you know it, you will have something worth thinking about to occupy your mind, and really big discoveries are the result of thought.

With every door that closes a new one opens.

The most successful men in the end are those whose success is the result of steady accretion.