He had not learned the principle--which half mankind do not seem ever to learn during the whole course of their lives--that it is far wiser and better to let our good qualities appear naturally of themselves, than to claim credit for them beforehand by boasting.

It would have been much wiser for Johnny to have admitted at the outset that Jane might possibly be taller than he, and then to have awaited quietly the result of the measuring.
But we can not blame him much for not having learned this particular wisdom at five years of age, when so many full-grown men and women never learn it at all.
Nor was there any thing blameworthy in him in respect to the false logic involved in his argument, that his being a boy made him necessarily taller than his cousin, a girl of the same age.

There was a _semblance_ of proof in that fact--what the logicians term a presumption.

But the reasoning powers are very slowly developed in childhood.

They are very seldom aided by any instruction really adapted to the improvement of them; and we ought not to expect that such children can at all clearly distinguish a semblance from a reality in ideas so extremely abstruse as those relating to the logical connection between the premises and the conclusion in a process of ratiocination.
In this case as in the other we expect them to understand at once, without instruction, what we find it extremely difficult to learn ourselves; for a large portion of mankind prove themselves utterly unable ever to discriminate between sound arguments and those which are utterly inconsequent and absurd.
In a word, what Johnny requires in such a case as this is, not ridicule to shame him out of his false reasoning, nor censure or punishment to cure him of his boasting, but simply instruction.
And this instruction it is much better to give _not_ in direct connection with the occurrence which indicated the want of it.