If a philosophic theory is once ruled out of court, no one can tell when it will appear again.

All logic texts are divided into two parts. In the first part, on deductible logic, the fallacies are explained; in the second part, on inductive logic, they are committed.

Inertia is the first law of history, as it is of physics.

Again, both literature and philosophy work by appealing to certain reigning idols.

The method of exposition which philosophers have adopted leads many to suppose that they are simply inquiries, that they have no interest in the conclusions at which they arrive, and that their primary concern is to follow their premises to their logical conclusions.

Lastly, literature and philosophy both allow past idols to be resurrected with a frequency which would be truly distressing to a sober scientist.

The business of the philosopher is well done if he succeeds in raising genuine doubt.