Make up your mind to act decidedly and take the consequences. No good is ever done in this world by hesitation.

Better live a crossing-sweeper than die and be made to talk twaddle by a "medium" hired at a guinea a seance.

The most considerable difference I note among men is not in their readiness to fall into error, but in their readiness to acknowledge these inevitable lapses.

The struggle for existence holds as much in the intellectual as in the physical world. A theory is a species of thinking, and its right to exist is coextensive with its power of resisting extinction by its rivals.

People never will recollect that mere learning and mere cleverness are of next to no value in life, while energy and intellectual grip, the things that are inborn and cannot be taught, are everything.

Matter and force are the two names of the one artist who fashions the living as well as the lifeless.

The man of science has learned to believe in justification, not by faith, but by verification.