The aim of science is not to open a door to infinite wisdom, but to set a limit to infinite error.

The thing that astonishes me is that the geologists and biologists seem quite unaware of the philosophical chaos that underlies their own work — they proceed as though the universe were already explained, and their only task were to fill in the details.

It is a test of true theories not only to account for but to predict phenomena. We ought to accept a theory if it predicts things which observation subsequently confirms, and if no rival theory is equally successful.

The human understanding is no dry light, but receives an infusion from the will and affections; whence proceed sciences which may be called 'sciences as one would.' For what a man had rather were true he more readily believes.