We notice the same essential difference in schoolboys and university students, and, in fact, in men of any age. Perhaps the majority of men, and less certainly of children, have but little sense of the implications of a statement. The sense of implications does not necessarily involve the ability to discover the implications--that is a comparatively rare gift. It acts rather in a negative manner, making the student restless under a subtly illogical presentation of a case, or leaving the schoolboy frankly mutinous at the end of a sermon. It is not a gift which makes a rapid learner, although its absence will prevent a man from ever knowing a subject properly. It is unfortunate that education, as practised in this country, does not sufficiently take into account this very desirable inhibition. The text-book plays a very large part in contemporary education, and most text-books are designed for those who can swallow statements at great speed. That delicate web of doubt, of half-seen alternative explanations, which comes into the mind of the intelligent student when confronted with the highly dogmatic statements and somewhat perfunctory “proofs” of many modern text-books, counts as sheer loss in the examination race. This is especially true of scientific text-books, which are usually conceived on an entirely wrong plan, judged from the standpoint of rational education. Statements which are the final expression of very difficult and slowly acquired abstractions are presented in all their nakedness, and followed by a collection of “examples.” The glib student learns these statements as if he were learning a foreign language, and soon masters the tricks necessary to apply them. I have known such students able to solve very difficult problems and yet entirely unable to meet, in any way, a sceptical attack upon the fundamental theorem they employ. The fact is that this method of teaching science is psychologically unnatural, and the knowledge acquired on this method is largely sham knowledge. While it may not be true that the child passes through “cultural epochs” in its mental growth, it is true that it will feel many of the hesitations and difficulties experienced by the men who first formulated the concepts now presented to it for its instant acceptance. It is for this reason that the best method of teaching a science is probably the historic method. In this way not only are many doubts fairly met instead of being merely repressed, but the exact _portée_ of a statement and possible lines of extension are much more clearly seen. The effect of the modern text-book is to make the intelligent student feel that he is remarkably unintelligent; the text-book writer is so terribly cocksure.