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

By no amount of reasoning can we altogether eliminate all contingency from our world. Moreover, pure speculation alone will not enable us to get a determinate picture of the existing world. We must eliminate some of the conflicting possibilities, and this can be brought about only by experiment and observation.

Liberalism regards life as an adventure in which we must take risks in new situation, in which there is no guarantee that the new will always be the good or the true, in which progress is a precarious achievement rather than inevitability.

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

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

Let philosophy resolutely aim to be as scientific as possible, but let her not forget her strong kinship with literature.

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