The accidental causes of science are only accidents relatively to the intelligence of a man.

We receive the truths of science by compulsion. Nothing but ignorance is able to resist them.

The very hope of experimental philosophy, its expectation of constructing the sciences into a true philosophy of nature, is basedon induction, or, if you please, the a priori presumption, that physical causation is universal; that the constitution of nature is written in its actual manifestations, and needs only to be deciphered by experimental and inductive research; that it is not a latent invisible writing, to be brought out by the magic of mental anticipation or metaphysical mediation.

What a fearful object a long-neglected duty gets to be

Let one persuade many, and he becomes confirmed and convinced, and cares for no better evidence.

A fact is a proposition of which the verification by an appeal to the primary sources of our knowledge or to experience is directand simple. A theory, on the other hand, if true, has all the characteristics of a fact except that its verification is possible only by indirect, remote, and difficult means.

The questions of philosophy proper are human desires and fears and aspirations - human emotions - taking an intellectual form.