The need to clarify our view on what is inherited and what is due to environment can be clearly envisaged in terms of our teachers. Whatever psychologists may mean by “predisposition to ability” it is quite certain that teachers make no distinction between this and the inheritance of a capacity. They feel that some children figure better than they read, and others read better than they figure, “by nature,” and there their obligation ends. If it is a grave matter that we shoulder the burden of bringing a child to his optimum achievement, then it is an immediate duty that we find how much of the failure to produce product of one kind or another is due to unremovable factors, and how much is due to our inadequacy. So, too, we have much loose discussion about finding out what children can do and want to do in the way of vocational diagnosis,—loose because it assumes that children are born with definite vocational capacities. Certainly we can do much more in the way of development and much more in the way of preparation for social needs if we know just how much “predisposition to ability” means. The teacher interprets it to mean about what was meant by the turtle that held up Atlas who held up the world. She makes no real distinction between predisposition to ability and specific ability, just as there was no real causal distinction between the turtle and Atlas. She then gets at her conception of intelligence additively,—a summation of school abilities. The correlation of teachers’ judgment of “power of adaptation,” carefully explained, and marks given six months previously by the same teachers was .82. The correlation of this same average judgment with the average of thirteen intelligence tests was only .58. These teachers obviously reached their conclusions of the intelligence of a child in the same way as they reached their conclusions of what marks he earned in their subjects. The unit characteristics which make up what we describe in terms of gross behavior as intelligence must of course be many. No one denies that if we knew just what these units were we could describe two possible manifestations of what we now call intelligence, of which one person could do one only and another person could do the other only because of the particular combinations of the units inherited. This would constitute inheritance of predisposition to special capacities. But it is not the same to assume that the vocations and aptitudes desirable in a world such as ours have specialized inherited bases. It is far more probable that substantially the same inherited characteristics are necessary to success in all the gross cross-sections of behavior which we call vocations and abilities.