J. B. S. Haldane

“I have no doubt that in reality the future will be vastly more surprising than anything I can imagine. Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.”

“My practice as a scientist is atheistic. That is to say, when I set up an experiment I assume that no god, angel, or devil is going to interfere with its course; and this assumption has been justified by such success as I have achieved in my professional career. I should therefore be intellectually dishonest if I were not also atheistic in the affairs of the world.”

“It seems to me immensely unlikely that mind is a mere by-product of matter. For if my mental processes are determined wholly by the motions of atoms in my brain I have no reason to suppose that my beliefs are true. They may be sound chemically, but that does not make them sound logically. And hence I have no reason for supposing my brain to be composed of atoms.”

“I had it for about fifteen years until I read Lenin and other writers, who showed me what was wrong with our society and how to cure it... Since then I have needed no magnesia.”

“An inordinate fondness for beetles.”

“I suppose the process of acceptance will pass through the usual four stages: (iv) I always said so.”

“An ounce of algebra is worth a ton of verbal argument.”

“No, but I would to save two brothers or eight cousins.”

“There is no great invention, from fire to flying, which has not been hailed as an insult to some god.”

“The conservative has little to fear from the man whose reason is the servant of his passions, but let him beware of him in whom reason has become the greatest and most terrible of passions. These are the wreckers of outworn empires.”

“The conservative has but little to fear from the man whose reason is the servant of his passions, but let him beware of him in whom reason has become the greatest and most terrible of the passions. These are the wreckers of outworn empires and civilisations, doubters, disintegrators, deiciders.”

“We must... carefully distinguish between two quite different doctrines which Darwin popularised, the doctrine of evolution, and that of natural selection. It is quite possible to hold the first and not the second. Similarly with regard to the doctrines of Darwin's great contemporary Marx, it is possible to adopt socialism but not historical materialism.”

“I do not propose to argue the case for evolution, which I regard as being quite as well proven as most other historical facts, but to discuss its possible causes, which are certainly debatable.”

“While the geneticists were disproving many of Darwin's ideas, the palaeontologists were determining the actual historical facts of evolution. ...they were able to verify the law of succession, first explicitly given by Darwin's colleague Wallace. "Every species has come into existence coincident, both in time and space, with a pre-existing closely allied species."”

“Comparative parasitology supports the evolutionary hypothesis. If two animals have a common ancestor, their parasites are likely to be descended from those of the ancestor. This principle has been applied with considerable effect to the classification of frogs and other groups.”

“The change from one stable equilibrium to the other may take place as the result of the isolation of a small unrepresentative group of the population, a temporary change in the environment which alters the relative viability of different types, or in several other ways...”

“If the only available genes produce rather large changes, disadvantageous one at a time, then it seems to me probable that evolution will not occur in a random mating population. In a self-fertilised or highly inbred species it may do so if several mutations useful in conjunction, but separately harmful, occur simultaneously. Such an event is rare, but must happen reasonably often in wheat...”

“If human evolution is to continue along the same lines as in the past, it will probably involve a still greater prolongation of childhood and retardation of maturity. Some of the characters distinguishing adult man will be lost. It was not an embryologist or palaeontologist who said, "Except ye . . . become as little children, ye shall not enter into the kingdom of heaven."”

“Unaided common sense may indicate an equilibrium, but rarely, if ever, tells us whether it is stable. If much of the investigation here summarised has only proved the obvious, the obvious is worth proving when this can be done. And if the relative importance of selection and mutation is obvious, it has certainly not always been recognised as such.”