case of complex personalities the matter stands thus: one of these can understand other men better than they can understand themselves, because within himself he has not only the character he is grasping, but also its opposite. Duality is necessary for observation and comprehension; if we inquire from psychology what is the most necessary condition for becoming conscious of a thing, for grasping it, we shall find the answer in "contrast." If everything were a uniform grey we should have no idea of colour; absolute unison of sound would soon produce sleep in all mankind; duality, the power which can differentiate, is the origin of the alert consciousness. Thus it happens that no one can understand himself were he to think of nothing else all his life, but he can understand another to whom he is partly alike, and from whom he is also partly quite different. Such a distribution of qualities is the condition most favourable for understanding. In short, to understand a man means to have equal parts of himself and of his opposite in one.
That things must be present in pairs of contrasts if we are to be conscious of one member of the pair is shown by the facts of colour-vision. Colour-blindness always extends to the complementary colours. Those who are red blind are also green blind; those who are blind to blue have no consciousness of yellow. This law holds good for all mental phenomena; it is a fundamental condition of consciousness. The most high-spirited people understand and experience depression much more than those who are of level disposition. Any one with so keen a sense of delicacy and subtilty as Shakespeare must also be capable of extreme grossness.
The more types and their contrasts a man unites in his own mind the less will escape him, since observation follows comprehension, and the more he will see and understand what other men feel, think, and wish. There has never been a genius who was not a great discerner of men. The great man sees through the simpler man often at a glance, and would be able to characterise him completely.
