Natural selection is not evolution.

The best causes tend to attract to their support the worst arguments, which seems to be equally true in the intellectual and in the moral sense.

The neutral zone of selective advantage in the neighbourhood of zero is thus so narrow that changes in the environment, and in the genetic constitution of species, must cause this zone to be crossed and perhaps recrossed relatively rapidly in the course of evolutionary change, so that many possible gene substitutions may have a fluctuating history of advance and regression before the final balance of selective advantage is determined.

The statistician cannot excuse himself from the duty of getting his head clear on the principles of scientific inference, but equally no other thinking man can avoid a like obligation.

Experimental observations are only experience carefully planned in advance, and designed to form a secure basis of new knowledge.

We have usually no knowledge that any one factor will exert its effects independently of all others that can be varied, or that its effects are particularly simply related to variations in these other factors.

In scientific subjects, the natural remedy for dogmatism has been found in research.