Common Sense is a science, whatever may be said; according to Yoritomo,
it does not blossom naturally in the minds of men; it demands
cultivation, and the art of reasoning is acquired like all the faculties
which go to make up moral equilibrium.

"This quality," said the philosopher, "is obscure and intangible, like
the air we breathe.

"Like the air we breathe, it is necessary to our existence, it surrounds
us, envelops us, and is indispensable to the harmony of our mental life.

"To acquire this precious gift, many conditions are obligatory, the
principle ones being:

"Sincerity of perception.

"Art of the situation.

"Attention.

"Approximation.

"Experience.

"Comparison.

"Analysis.

"Synthesis.