It happens, however, that the way leads also through the cross-roads; it is even indispensable to leave the short cuts in order to trace the outline of the obstacles.
Direction is, then, an important factor in the acquiring of common sense.
The putting of the question takes its character from comparison, from experience, and principally from approximation; but it is in itself a synthesis of all the elements which compose common sense.
He who wishes to acquire common sense should be impregnated with all that has preceded.
Then he will discipline himself, so as to be able to judge, by himself, of the degree of reason which he has the right to assume.
He will begin by evoking some subject, comparing its visual forms with, those forms which he understands the best, in other words, to the perceptions which are the most familiar to him.
If it concerns a question to be solved, he will try to recall some similar subject, and establish harmony, by making them both relative to a common antecedent.
Yoritomo advises choosing simple thoughts for the beginning.
"One will say, for example:
"Such a substance is a poison; the seeds of this fruit contain a weak dose of it; these seeds could then become a dangerous food, if one absorbed a considerable quantity.