Whenever we're afraid, it's because we don't know enough. If we understood enough, we would never be afraid.

I do not fear death. I had been dead for billions and billions of years before I was born, and not suffered the slightest inconvenience from it.

He who possesses most must be most afraid of loss.

I've had a lot of worries in my life, most of which never happened.

To make a contented slave it is necessary to make a thoughtless one. It is necessary to darken the moral and mental vision and, as far as possible, to annihilate the power of reason.

I keep six honest serving men (they taught me all I knew); Their names are What and Why and When And How and Where and Who.

When I examine myself and my methods of thought, I come to the conclusion that the gift of fantasy has meant more to me than my talent for absorbing positive knowledge.

When you know a thing, to hold that you know it; and when you do not know a thing. To allow that you do not know it—this is knowledge.

To furnish the means of acquiring knowledge is the greatest benefit that can be conferred upon mankind. It prolongs life itself and enlarges the sphere of human existence.

When you fear something, learn as much about it as you can. Knowledge conquers fear.

It is always advisable to perceive clearly our ignorance.

There is a wisdom in this beyond the rules of physic. A man’s own observation, what he finds good of and what he finds hurt of, is the best physic to preserve health.

A little knowledge that acts is worth infinitely more than much knowledge that is idle.