We cannot think first and act afterwards. From the moment of birth we are immersed in action and can only guide it by taking thought. - Alfred North Whitehead

From the moment of birth we are immersed in action, and can only fitfully guide it by taking thought.

All science must start with some assumptions as to the ultimate analysis of the facts with which it deals. These assumptions are justified partly by their adherence to the types of occurrence of which we are directly conscious, and partly by their success in representing the observed facts with a certain generality, devoid of ad hoc suppositions.

The point about zero is that we do not need to use it in the operation of daily life. No one goes out to buy zero fish.

If science is not to degenerate into a medley of ad hoc hypotheses, it must become philosophical and must enter upon a thorough criticism of its own foundations.