And it may be universally affirmed that, where this the form is, there the thing sought is also, and where it is not, there the thing cannot be.(147) Nothing is to be received for the true scientific cause, unless the thing of which it is the cause, increases and decreases along with it.(148)This difference, indeed, between common practical observations and rules, and general scientific principles must always exist, for it springs from the different nature of the one and the other.The observations which the man of practice makes, as has been already remarked, are on phenomena, the results of the play of real principles, and as these principles may vary in their proportions to each other, and in the modes in which their powers are exerted, the results produced by their action must occasionally vary.The principles themselves, however, never vary; and, therefore, one observation or experiment concerning a real principle, if there be no inaccuracy in it, has always in science been esteemed as good as a thousand.The whole inductive philosophy may, indeed, be said to rest on the impossibility of the occurrence of exceptions to real laws.Hence the extensive use of negative instances, determining, at last, what is a principle by pointing out what it is not.
Again; it is far from being the case, that a regard for self-interest, a desire of battering one's condition, prompts always to a course of action leading to an increase of even private fortune.This must depend on what is esteemed the best condition, -- on what one's happiness rests.(149) Hence what has been regarded as the most enlightened self-interest, has often led, as we have seen, to a course of action the very reverse.The Romans, under the emperors, were assuredly as earnest in their quest after happiness, as were ever any race, yet their manners, and their whole practical morality tended to the diminution of wealth previously accumulated, and they swallowed up, in extravagant dissipation, the riches of kingdoms.
Nor let it be here answered, that facts applicable to the Romans, or other people of habits and modes of thinking and acting unlike those characterizing the civilized world of modern days, cannot be fairly adduced in investigations concerning existing systems of society.This is indeed true, if the reasonings in the Wealth of Nations be admitted to be of the systematic and explanatory cast, but not if that work he maintained to be an inductive inquiry.These remote and heterogeneous instances, are the very ones which experimental science most prizes, (150) and this, for the reason just adduced, that real principles being constant in their action, what are, and what are not the principles inquired after, are thus tested.(151)III.The actual history of what is termed the science of political economy, is another mode of ascertaining the justice of its pretensions to that appellation.By comparing it with the generic character of the history of philosophical sects of the explanatory and systematic form, given by the founder of the inductive philosophy, as contrasted with what he pointed out was to be expected from that philosophy, and time has shown it hopes accomplished, we might have farther grounds to come to a conclusion on the question.To do this at length, however, would lead us too far beyond limits, which I have already exceeded.I shall, therefore, confine the few farther observations I have to make, to one circumstance, which Lord Bacon gives as characteristic of the two sects.In his figurative language " the path which the inductive philosophy takes, is at first steep and difficult, but leads to an open country, while that adopted by the explanatory and systematic, though at first easy and inviting, is at last lost in deserts or conducts to precipices." (152)The doubts and difficulties in which the progress of those has been involved, who have advanced farthest along the apparently safe and easy road that Adam Smith seemed to have opened up, indicate it not to be the path of science.Of these I shall adduce a few instances.
Capital is uniformly treated of in the Wealth of Nations, as a thing homogeneous in its nature, having always the same qualities, (according to the definition of Mr.Say, an amount of values,) and any increase or diminution of it, as a mere alteration in quantity.This being taken to be the case, as like causes produce like effects, it seems very evidently to follow, that the only manner in which a change can be produced in the returns yielded by it, must be by the labor that it employs, absorbing a larger or smaller part of them.This result is not uniformly kept in view in the Wealth of Nations, though it is very frequently brought forward.
