"Then follow the innumerable categories of sound that we distinguish only by means of comprehension and reflection, rendered so instinctive by habit that we may call them automatic, so far as those which relate to familiar sounds. "The example which we have just given is a proof of this fact. "Let us add that this habit develops each sensitive faculty to its highest degree. "The inhabitants of the country can distinguish each species of bird by listening to his song; and the hermits, the wanderers, those who live with society on a perpetual war footing, perceive sounds which would not strike the ears of civilized people. "Approximation is also one of the stones by whose aid we construct the edifice of common sense. "Concerning the calculations of probabilities, the application of approximation will allow us to estimate the capacity or the probable duration of things. "We can not say positively whether a man will live a definite number of years but we can affirm that he will never live until he is two hundred. "There are, for approbation, certain known limits which serve as a basis for the construction of reasoning, inspired by common sense. "It can be affirmed, in a positive way, that, if the trunk of a tree were floating easily, without sinking to the bottom of the water, it would not float the same if thirty men were to ride astride of it. "The initial weight of the tree permits it to maintain itself on the surface; but if it be increased to an exaggerated total, we can, without hesitation, calculate indirectly the moment when it will disappear, dragging with it the imprudent men who trusted themselves to it. "Everything in life is a question of approximation. "The house which is built for a man will be far larger than the kennel, destined to shelter a dog, because the proportions have been calculated, by approximation, according to the relative difference between the stature of the human and canine species. "Clothing is also suited to the temperature. "One naturally thinks that, below a certain degree of cold, it is necessary to change light clothes for those made of thicker material. "As with the majority of the constructive elements of common sense, approximation is always based on experience. "It draws its conclusions from the knowledge of known limitations, whose affirmation serves as a basis for the argument which determines deduction in a most exact manner. "Experience itself depends on memory, which permits us to recall facts and to draw our conclusions from them, on which facts reasoning is based." The Shogun does not fail to draw our attention to the difference between experience and experimentation. "This last," said he, "only serves to incite the manifestation of the first. "It consists of determining the production of a phenomenon whose existence will aid us in establishing the underlying principles of an observation which interprets the event. "That is what is called experience.