The symbol and the metaphor are as necessary to science as to poetry. - Jacob Bronowski

Human beings can imagine situations which are different from those in front of their eyes... because they make and hold in their minds images for absent things.

But it is of critical importance to ask ourselves what features which other animals do not possess have given human beings the very special capacities with which we are concerned in these lectures: the ability to utter cognitive sentences (which no other animal can do) and the ability therefore to exercise knowledge and imagination.

The hand is the cutting edge of the mind. Civilisation is not a collection of finished artefacts, it is the elaboration of processes. In the end, the march of man is the refinement of the hand in action.