He adopts in them the hypothesis that the pleasure they give arises from some difficulty in the execution being overcome, and it seems to have been his intention to build up a whole system dart on this principle.Perhaps no circumstance can be found, running more through all the arts, and, therefore, better fitted for the connecting purposes of the system-builder, or, on the other hand, more curious in itself, and which, therefore, the inductive philosopher would be more inclined to inquire into.How is it, that the images of the poet come upon us with most force, when he puts his words into measured cadence? How is it that an ideal form, if struck out of marble, affects us so much more than if moulded in wax? Is it that the spirit;when fully roused, and striving to embody some great sentiment, or strong emotion, naturally seizes on the materials which may best betoken energy, and thus contrives to give an additional air of intellectuality to mere matter? -- This or a series of such questions present themselves to the inductive inquirer.What to the systematic philosopher affords the means of explaining other things, is to him the subject itself of inquiry.
But, of all his speculations, there is none in which he seems to be more completely the philosopher of system and explanation than in the Wealth of Nations.It is a system entirely founded on the most common and familiar notions, and proceeds altogether on the generalization of them.Value, riches, stock, capital, wealth, profit, self-interest, the desire of bettering one's condition , are evidently of this sort.They are manifestly terms of ill-defined import, referring to notions drawn hastily, and confusedly, from the course of passing events; "notiones confusae, et ternere a rebus abstractae." And the strain of his reasoning upon them is that proper to the philosophy of system, which, taking from experience the most common and familiar observations, applies itself not to inquire into them, but to form a theory out of them."Rationale enim genus philosophantium ex experientia arripiunt varia et vulgaria, eaque neque certo comperta, nec diligenter examinata et pensitata; reliqua meditatione, atque ingenii agitatlone ponunt." If we, therefore, view his work as au attempt to establish the science of wealth, on the principles of the experimental or inductive philosophy, it is exposed to the censure of transgressing every rule of that philosophy.
"Men are inclined to think that it is not necessary to inquire into the causes of events that are common and happen every day, but, taking them for things too evident and manifest to require explanation, assume them as causes sufficiently accounting for phenomena, that are not of so frequent and familiar occurrence.Whereas, in reality, no judgment can be formed of events which are rare and remarkable, nor can any thing new be brought to light, without an accurate investigation of the causes, and even the causes of the causes of things, that are the most common and familiar." (138)The reason of this will be evident, by referring to the example before adduced.Ira man, as in the case of the savage, who is totally unacquainted with the system of things but as they present themselves to the eye of the practical observer, be asked why a stone falls to the ground, he would answer, "it is its nature, all heavy bodies fall to the ground." "Why does smoke ascend?" "It is its nature, all light bodies mount' upwards." "Why, when a stone is seen flying through the air, do you look about to find out the reason of it?" "Because it is against its nature, and I know, therefore, it must have been produced by violence -- by some external force." Thus, too, among mere practical observers of events, there would come to be the terms gravity, levity, natural and violent motion.Now all these words and phrases, if correctly interpreted, are perfectly correct, according to the measure of the knowledge of the individuals, and assume nothing but what their experience warrants.When it is said that smoke ascends in consequence of its levity, or because it is the nature of it and other light bodies to ascend, nothing more is necessarily implied in the words than that there is something, -- what is not known, -- arising from the general constitution of things, from the system of nature itself, causing that ascent, and that, while this general constitution of things remains unaltered, all such bodies will ascend.So it is when it is said that it is against the nature of a stone to move in any direction but downwards, and that its other motions must be violent.The expressions, in strictness, mean nothing more than that unless acted on by some extraneous cause, while the present condition of things lasts, if it move at all, its motion will be directly downwards.All these are conclusions drawn from experience, and form general rules of real practical utility.Science will never teach the savage to shape, to trim, or to preserve the poise of his canoe, better than observations similar to these have already taught him.