When Galton questioned persons whom he met in general society he found "an entirely different disposition to prevail. Many men and a yet larger number of women, and many boys and girls, declared that they habitually saw mental imagery, and that it was perfectly distinct to them and full of color." The evidence of this difference between the psychology of the average distinguished scientist and the average member of general society was greatly strengthened upon cross-examination. Galton attributed the difference to the scientist's "habits of highly generalized and abstract thought, especially when the steps of reasoning are carried on by words [employed] as symbols." It is only by the use of words as symbols that scientific thought is possible. It is through coöperation in work that mankind has imposed its will upon the creation, and coöperation could not have been carried far without the development of language as a means of communication. Were it not for the help of words we should be dependent, like the lower animals, on the fleeting images of things. We should be bound to the world of sense and not have range in the world of ideas. Words are a free medium for thought, for the very reason that they are capable of shifting their meaning and taking on greater extension or intension. For example, we may say that the apple falls because it is heavy, or we may substitute synonymous phraseology that helps us to view the falling apple in its universal aspects. The mind acquires through language a field of activity independent of the objective world. We have seen in an earlier chapter that geometry developed as a science is becoming gradually weaned from the art of surveying. Triangles and rectangles cease to suggest meadows, or vineyards, or any definite imagery of that sort, and are discussed in their abstract relationship. Science demands the conceptual rather than the merely sensory. The invisible real world of atoms and corpuscles has its beginning in the reason, the word. To formulate new truths in the world of ideas is the prerogative of minds gifted with exceptional reason.