"And, altho recognizing the truth of these two opinions, so contradictory, I could not help thinking that they were the reproduction of those which men, deprived of common sense, express every day. "The same hill produced a vegetation, affected in different ways, by reason of different causes; and the people, instead of taking into consideration how carelessly they had chosen the location of their plantation, preferred to attribute the defect to the site itself, rather than to their lack of precaution. "Both of them were suffering from a hurtful exaggeration, but each one explained it in a way arbitrarily exclusive. "He of the north made out that the sun never shone on the summit of Yung-Tshi, and the inhabitant of the south affirmed that the health-giving shade was unknown there." This is why it is indispensable to the successful resolution of the thousand and one problems of daily life, both those whose sole importance is derived from their multiplicity and those whose seriousness justly demands our attention, to employ the very simple method which prescribes that we place ourselves mentally in the position and circumstances of the person with whom we are discussing. If each one of the inhabitants of Yung-Tshi had followed this precept, instead of declaring that the hill never received the sun or that shade never fell upon it, they would each one have thought for himself. "At what conclusions should I arrive, if I had planted my trees on the opposite side?" From the reasoning which would have ensued, the following truth would most certainly have been revealed. "If I were in the other man's place, I should certainly think as he does." This premise once laid down, the conclusion would be reached; all the more exact, because, without abandoning their arguments, each one would present those which it is easy to turn against an adversary. Before solving a problem, he who desires to avoid making a mistake must never fail to ask himself this question: What should I do if my interests were those of the opposite party? Or, yet again: What should I reply if my adversaries used the same language to me as I purpose using when addressing them? This method is valuable in that it raises unexpected objections, which the mind would not consider if one had simply studied the question from one's own point of view. It is a self-evident fact that, according to the state of mind in which we are, things assume different proportions in the rendering of judgment on them. We must not argue as children do, who, not having the sense of calculating distances, ask how the man standing near to them will be able to enter his house, which they see far away, and which seems to them of microscopic dimensions. One departs from common sense when one attributes to insignificant things a fundamental value.