The small boy learns the wisdom of moderation from the stomach-ache which follows too much plum-pudding or too many green apples—if the pain is often enough repeated. The matter, however, is apt to present itself to his mind as a sort of tacit bargain between himself and Fate: so many green apples, so much stomach-ache; so much self-indulgence and so much pain, and the account is balanced. Life is not so simple as this; and that Fate does not make bargains so direct is learned from experience so gradually as often to be learned too late. To tell this to a child is of very little effect; for even if he believes it with his childish intelligence, he can hardly feel the intimate links which bind all humanity together, and make him subject to the same conditions that rule his elders and instructors. The phrase "realities of life," moreover, includes not only sensible—that is, material—facts and conditions, but the more subtle things of inner existence. A hundred persons are able to gather facts, while very few are capable of drawing from them adequate conclusions or of perceiving how one truth bears upon another. A very moderate degree of intelligence is required for analysis as compared to that necessary for synthesis. The power "to put two and two together," as the common phrase has it, grows slowly in the mind of a child. Within a limited range children appreciate that one fact is somehow joined to another; and indeed the education which life gives consists chiefly in expanding this perception. The connection between touching a hot coal and being burned brings home the plain physical relations early. The connection between disobedience and unpleasant consequences will be borne in upon the youthful consciousness according to the sharpness of discipline by which it is enforced; and so on to the end of the chapter. To perceive a relation and to appreciate what that relation is are, however, different matters. The understanding of the nature of breaking rules and suffering in consequence involves a perception of underlying principle, and some comprehension of the real nature of these principles.