Clear thinking is a question of knowing one's own limits, while trying of course to extend them, and of accepting them, so that each climb is adapted to one's own capabilities and to those of the rope as a whole.

During the climb, it means being able to make an honest assessment of the situation, not so easily done as it means being able to stand back and evaluate, uninfluenced by one's emotions or one's most ardent ambitions, the difficulties (or indeed dangers) remaining on the climb, as compared with the strength (mental and physical) of the party, so that an intelligent decision can be made whether to go on or turn back.

This is an extraordinary and very rewarding self-examination, requiring exact analysis: prudence can often be confused with a sort of cowardice and a stubborn refusal to be turned back could be simply pig-headedness.