On religion in particular, the time appears to me to have come, when it is a duty of all who, being qualified in point of knowledge, have, on mature consideration, satisfied themselves that the current opinions are not only false, but hurtful, to make their dissent known.

And it is not difficult to show, by abundant instances, that to extend the bounds of what may be called moral police, until it encroaches on the most unquestionably legitimate liberty of the individual, is one of the most universal of all human propensities.

A person whose desires and impulses are his own - are the expression of his own nature, as it has been developed and modified by his own culture - is said to have a character. One whose desires and impulses are not his own, has no character, no more than a steam-engine has character.

I have learned to seek my happiness by limiting my desires, rather than in attempting to satisfy them.

The ends of scientific classification are best answered, when the objects are formed into groups respecting which a greater number of general propositions can be made, and those propositions more important, than could be made respecting any other groups into which the same things could be distributed. ... A classification thus formed is properly scientific or philosophical, and is commonly called a Natural, in contradistinction to a Technical or Artificial, classification or arrangement.

Truth emerges from the clash of adverse ideas.

Men are men before they are lawyers, or physicians, or merchants, or manufacturers; and if you make them capable and sensible men, they will make themselves capable and sensible lawyers or physicians.