Next to selfishness the principal cause which makes life unsatisfactory is want of mental cultivation.

What distinguishes the majority of men from the few is their inability to act according to their beliefs.

As long as justice and injustice have not terminated their ever renewing fight for ascendancy in the affairs of mankind, human beings must be willing, when need is, to do battle for the one against the other.

The process of tracing regularity in any complicated, and at first sight confused, set of appearances, is necessarily tentative; we begin by making any supposition, even a false one, to see what consequences will follow from it ; and by observing how these differ from the real phenomena, we learn what corrections to make in our assumption.

The application of algebra to geometry ... has immortalized the name of Descartes, and constitutes the greatest single step ever made in the progress of the exact sciences.

Any participation, even in the smallest public function, is useful.

The individual is not accountable to society for his actions in so far as these concern the interests of no person but himself.