It is only common sense which will indicate the course of conduct to be pursued, so as not to hurt the feelings or offend the prejudices of other people.
There are great savants, whose science, freed from all puerile beliefs, rises above current superstition.
They would consider it a great lack of common sense if they expounded their theories before the humble-minded, whose blind faith would be injured thereby.
Of two things one is certain: either they would refuse to believe such theories and this display of learning would be fruitless, or their habitual credulity would be troubled and they would lose their tranquility without acquiring a conviction sufficiently strong to give them perfect peace of mind.
Even in things which concern health, common sense is applicable to daily life.
It is common sense which will preserve us from excesses, by establishing the equilibrium of the annoyances which result from them, with reference to the doubtful pleasure which they procure.
Thanks to common sense, we shall avoid the weariness of late nights and the danger of giving oneself up to the delights of dissipation.
"It is common sense," says the philosopher, "which forces us at a banquet to raise our eyes to the hour-glass to find out how late it is.
"It is under the inspiration of this great quality of mind that we shall avoid putting to our lips the cup already emptied many times.
"Common sense will reflect upon the mirror of our imagination the specter of the day after the orgy; it will evoke the monster of the headache which works upon the suffering cranium with its claws of steel; and, at some future day, it will show us precocious decrepitude as well as all bodily ills which precede the final decay of those who yield to their passions. It will also impose upon us the performance of duty under the form which it has adopted for each individual.
"Common sense represents for some the care of public affairs; for others those of the family; for us all the great desire to leave intact to our descendants the name which we have received from our fathers.
"For some of those still very young, it is like a lover long desired!
"For sages and warriors, it blows the trumpet of glory.
"Finally, common sense is the chosen purpose of every one, courted, demanded, desired or accepted, but it exists, and under the penalty of most serious inconveniences it does not permit us to forget its existence."
Coming down from the heights where he allows himself to be transported at times for a brief moment, Yoritomo tells us the part played by common sense with reference to health.
"Common sense" he assures us, "is the wisest physician whom it is possible to consult.
"If we followed its advice, we should avoid the thousand and one little annoyances of illnesses caused by imprudence.
"The choice of clothing would be regulated according to the existing temperature.
"One would avoid the passing at once from extreme heat to extreme cold.
"One would never proffer this stupid reflection: Bah! I shall take care of myself, which impudent people declare when exposing themselves carelessly to take cold.
"We should understand that disease is a cause of unparalleled disorder and discord.
"In addition to the thought of possible sufferings, that of grief for those whom we love, joined to the apprehension of a cessation of social functions, on whose achievement depends our fortune, would suffice to eliminate all idea of imprudence, if we had the habit of allowing common sense to participate in all our actions of daily life.
"To those who walk under its guidance; it manifests itself without ceasing; it dominates all actions without their being compelled to separate themselves from it.
"It is unconsciously that they appeal to common sense and they have no need of making an effort to follow its laws.
"Common sense is the intelligence of instinct."
LESSON VII
POWER OF DEDUCTION
Before entering the path which relates directly to the intellectual efforts concerning the acquisition of common sense, the Shogun calls our attention to the power of deduction.
"It is only," said he, "where we are sufficiently permeated with all the principles of judgment that we shall be able to think of acquiring this quality, so necessary to the harmony of life.
"The most important of all the mental operations which ought to be practised by him who desires common sense to reign supreme in all his actions and decisions, is incontestably deduction.
"When the union of ideas, which judgment permits, is made with perception and exactness, there results always an analysis, which, if practised frequently, will end by becoming almost a mechanical act.
"It is, however, well to study the phases of this analysis, in order to organize them methodically first.
"Later, when the mind shall be sufficiently drilled in this kind of gymnastics, all their movements will be repeated in an almost unconscious way, and deduction, that essential principle of common sense, will be self-imposed.
"In order that deductions may be a natural development, the element relating to those which should be the object of judgment should be grouped first.
"The association of statements is an excellent method for it introduces into thought the existence of productive agents.
"We have already spoken of the grouping of thoughts, which is a more synthetical form of that selection.
"Instead of allowing it to be enlarged by touching lightly on all that which is connected with the subject, it is a question, on the contrary, of confining it to the facts relating to only one object.
"These facts should be drawn from the domain of the past; by comparison, they can be brought to the domain of the present in order to be able to associate the former phenomena with those from which it is a question of drawing deductions.
"It is rarely that these latter depend on one decision alone, even when they are presented under the form of a single negation or affirmation.
"Deduction is always the result of many observations, formulated with great exactness, which common sense binds together.
"That which is called a line of action is always suggested by the analysis of the events which were produced under circumstances analogous to those which exist now.
"From the result of these observations, the habit of thinking permits of drawing deductions and common sense concludes the analysis.
"The method of deduction rests upon this.
"One thing being equal to a previous one should produce the same effects.
"If we find ourselves faced by an incident that our memory can assimilate with another incident of the same kind, we must deduce the following chain of reasoning:
"First, the incident of long ago has entailed inevitable consequences.
"Secondly, the incident of to-day ought to produce the same effects, unless the circumstances which surround it are different.
"It is then a question of analyzing the circumstances and of weighing the causes whose manifestation could determine a disparity in the results.