The clergy are at present divided into three sections: an immense body who are ignorant; a small proportion who know and are silent; and a minute minority who know and speak according to their knowledge.

If there is anything in the world which I do firmly believe in, it is the universal validity of the law of causation.

If a little knowledge is dangerous, where is the man who has so much as to be out of danger?

Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle. ... Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable.

For these two years I have been gravitating towards your doctrines, and since the publication of your primula paper with accelerated velocity. By about this time next year I expect to have shot past you, and to find you pitching into me for being more Darwinian than yourself. However, you have set me going, and must just take the consequences, for I warn you I will stop at no point so long as clear reasoning will take me further.

Only one absolute certainty is possible to man, namely that at any given moment the feeling which he has exists.

Science is simply common sense at its best.