The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.

As to sagacity, I should say that his judgement respecting the warmest place and the softest cushion in a room is infallible, his punctuality at meal times is admirable, and his pertinacity in jumping on people's shoulders till they give him some of the best of what is going, indicates great firmness.

I can assure you that there is the greatest practical benefit in making a few failures early in life. You learn that which is of inestimable importance that there are a great many people in the world who are just as clever as you are. You learn to put your trust, by and by, in an economy and frugality of the exercise of your powers, both moral and intellectual; and you very soon find out, if you have not found it out before, that patience and tenacity of purpose are worth more than twice their weight of cleverness.

It is not what we believe, but why we believe it. Moral responsibility lies in diligently weighing the evidence. We must actively doubt; we have to scrutinize our views, not take them on trust. No virtue attached to blindly accepting orthodoxy, however 'venerable'.

Irrationally held truths may be more harmful than reasoned errors.

The results of political changes are hardly ever those which their friends hope or their foes fear.

I am content with nothing, restless and ambitious... and I despise myself for the vanity, which formed half the stimulus to my exertions. Oh would that I were one of those plodding wise fools who having once set their hand to the plough go on nothing doubting.