There is always need of persons not only to discover new truths, and point out when what were once truths are true no longer, but also to commence new practices, and set the example of more enlightened conduct, and better taste and sense in human life.

Originality is the one thing which unoriginal minds cannot feel the use of.

Ask yourself whether you are happy, and you cease to be so.

The world would be astonished if it knew how great a proportion of its brightest ornaments, of those distinguished even in popular estimation for wisdom and virtue, are complete sceptics in religion.

The peculiarity of the evidence of mathematical truths is that all the argument is on one side.

Genius can only breathe freely in an atmosphere of freedom.

It is not the feeling sure of a doctrine (be it what it may) which I call an assumption of infallibility. It is the undertaking to decide that question for others, without allowing them to hear what can be said on the contrary side. And I denounce and reprobate this pretension not the less, if put forth on the side of my most solemn convictions.