No morality can be founded on authority, even if the authority were divine. -- A. J. Ayer

Metaphysics is the finding of bad reasons for what we believe upon instinct... -- Francis Bradley

You are a philosopher, Dr. Johnson. I have tried too in my time to be a philosopher; but I don't know how, cheerfulness was always breaking in. -- Oliver Edwards

The great tragedy of Science - the slaying of a beautiful hypothesis by an ugly fact. -- Thomas Huxley

No one can be a great thinker who does not recognize...it is his first duty to follow his intellect to whatever conclusions it may lead. -- J. S. Mill

It is not he who reviles or strikes you who insults you, but your opinion that these things are insulting. -- Epictetus

It is only our bad temper that we put down to being tired or worried or hungry; we put our good temper down to ourselves. -- C. S. Lewis

It is easier to fight for one's principles than to live up to them. -- Alfred Adler