The fidelity of a dog is a precious gift.

The scientist knows very well that he is approaching ultimate truth only in an asymptotic curve and is barred from ever reaching it; but at the same time he is proudly aware of being indeed able to determine whether a statement is a nearer or a less near approach to the truth.

The fidelity of a dog is a precious gift demanding no less binding moral responsibilities than the friendship of a human being.

All living beings have received their weapons through the same process of evolution that moulded their impulses and inhibitions; for the structural plan of the body and the system of behaviour of a species are parts of the same whole.... Wordsworth is right: there is only one being in possession of weapons which do not grow on his body and of whose working plan, therefore, the instincts of his species know nothing and in the usage of which he has no correspondingly adequate inhibition.

The distance at which all shooting weapons take effect screens the killer against the stimulus sensation which would otherwise activate his killing inhibitions. The deep, emotional layers of our personality simply do not register the fact that the crooking of the finger to release a shot tears the entrails of another man.

Natural selection does not give any preference at all to anything that, in the long run, could be advantageous for the species but blindly rewards everything that, momentarily, affords greater procreative success.

All scientific knowledge to which man owes his role as master of the world arose from playful activities.