It is very much easier to divide your outlook on the world into two halves, to say that you know this belongs to the daily half and this belongs to the Sunday half.

Science is a tribute to what we can know, although we are fallible.

Astronomy is not the apex of science or of invention. But it is a test of the cast of temperament and mind that underlies a culture.

The men who made the Industrial Revolution are usually pictured as hardfaced businessmen with no other motive than self-interest. That is certainly wrong. For one thing, many of them were inventors who had come into business that way.

Science is the acceptance of what works and the rejection of what does not. That needs more courage than we might think.

Sex was invented as a biological instrument by (say) the green algae. But as an instrument in the ascent of man which is basic to his cultural evolution, it was invented by man himself.

The hand is the cutting edge of the mind.