The exercise of voluntary attention in the schoolroom must therefore be counted one of the most important points of training that take place there; and the first-rate teacher, by the keenness of the remoter interests which he is able to awaken, will provide abundant opportunities for its occurrence.

Many persons nowadays seem to think that any conclusion must be very scientific if the arguments in favor of it are derived from twitching of frogs' legs (especially if the frogs are decapitated) and that, on the other hand, any doctrine chiefly vouched for by the feelings of human beings (with heads on their shoulders) must be benighted and superstitious.

Theory must mediate between all previous truths and certain new experiences

Man lives for science as well as bread.

Science herself consults her heart when she lays it down that the infinite ascertainment of fact and correction of false belief are the supreme goods for man.

If it works, it's true.

Those thoughts are truth which guide us to beneficial interaction with sensible particulars as they occur, whether they copy these in advance or not.