Now in creative thought common sense is a bad master. Its sole criterion for judgement is that the new ideas shall look like the old ones. In other words it can only work by suppressing originality.
Alfred North WhiteheadThe whole of mathematics consists in the organization of a series of aids to the imagination in the process of reasoning.
Alfred North WhiteheadWithout adventure civilization is in full decay. ... The great fact [is] that in their day the great achievements of the past were the adventures of the past.
Alfred North Whitehead