From the dawn of exact knowledge to the present day, observation, experiment, and speculation have gone hand in hand; and, whenever science has halted or strayed from the right path, it has been, either because its votaries have been content with mere unverified or unverifiable speculation (and this is the commonest case, because observation and experiment are hard work, while speculation is amusing); or it has been, because the accumulation of details of observation has for a time excluded speculation.

Make up your mind to act decidedly and take the consequences. No good is ever done in this world by hesitation.

I took thought, and invented what I conceived to be the appropriate title of 'agnostic'.

For myself I say deliberately, it is better to have a millstone tied round the neck and be thrown into the sea than to share the enterprises of those to whom the world has turned, and will turn, because they minister to its weaknesses and cover up the awful realities which it shudders to look at.

Follow humbly wherever and to whatever abyss Nature leads, or you shall learn nothing.

There is far too much of the feeding-bottle in education and young people ought to be supplied with good intellectual food and then left to help themselves.

. . . I fail to find a trace [in Protestantism] of any desire to set reason free. The most that can be discovered is a proposal to change masters. From being a slave of the papacy, the intellect was to become the serf of the Bible.