All that passes for knowledge can be arranged in a hierarchy of degrees of certainty, with arithmetic and the facts of perception at the top.

To like many people spontaneously and without effort is perhaps the greatest of all sources of personal happiness.

It is no credit to the orthodox that they do not now believe all the absurdities that were believed 150 years ago. The gradual emasculation of the Christian doctrine has been effected in spite of the most vigorous resistance, and solely as the result of the onslaughts of freethinkers.

It can be shown that a mathematical web of some kind can be woven about any universe containing several objects. The fact that our universe lends itself to mathematical treatment is not a fact of any great philosophical significance.

Moral progress has consisted in the main of protest against cruel customs, and of attempts to enlarge human sympathy.

If throughout your life you abstain from murder, theft, fornication, perjury, blasphemy, and disrespect toward your parents, church, and your king, you are conventionally held to deserve moral admiration even if you have never done a single kind, generous or useful action. This very inadequate notion of virtue is an outcome of taboo morality, and has done untold harm.

My own view on religion is that of Lucretius. I regard it as a disease born of fear and as a source of untold misery to the human race. I cannot, however, deny that it has made some contributions to civilisation. It helped in early days to fix the calendar, and it caused Egyptian priests to chronicle eclipses with such care that in time they became able to predict them. These two services I am prepared to acknowledge, but I do not know of any others.