So many of the chemical reactions occurring in living systems have been shown to be catalytic processes occurring isothermally on the surface of specific proteins, referred to as enzymes, that it seems fairly safe to assume that all are of this nature and that the proteins are the necessary basis for carrying out the processes that we call life.

The question of the origin of life is essentially speculative. We have to construct, by straightforward thinking on the basis of very few factual observations, a plausible and self-consistent picture of a process which must have occurred before any of the forms which are known to us in the fossil record could have existed.

The problem [of specialization] is essentially that of communications to an army in action. After a rapid advance communications become disorganized, and there is a temporary halting until they are again in working order.

Men will not be content to manufacture life: they will want to improve on it.

The human mind evolved always in the company of the human body, and of the animal body before it was human. The intricate connections of mind and body must exceed our imagination, as from our point of view we are peculiarly prevented from observing them.

Scientific corporations might well become almost independent states and be enabled to undertake their largest experiments without consulting the outside world - a world which would be less and less able to judge what the experiments were about.

The only way of learning the method of science is the long and bitter way of personal experience.