sciences, and by which they are distinguished from many of the physical; that is, that it is seldom in our power to make experiments in them. In chemistry and natural philosophy, we can not only observe what happens under all the combinations of circumstances which nature brings together, but we may also try an indefinite number of new combinations. This we can seldom do in ethical and scarcely ever in political science. We cannot, try forms of government, and systems of national policy, on a diminutive scale, in our laboratories; shaping our experiments as we think that they may most conduce to the advancement of knowledge. We therefore study Nature under circumstances of great disadvantage in these sciences, being confined to the limited number of experiments which take place (if we may so speak) of their own accord, without any preparation or management of ours, in circumstances, moreover, of great complexity, and never perfectly known to us, and with the far greater part of the processes concealed from our observation.

"The consequence of this invariable defect in the materials of this induction, is that we can rarely obtain what Bacon has quaintly, but not unaptly, termed an experimentum crucis."1 Also-"Since, therefore, it is vain to hope that truth can be arrived at, either in Political Economy or in any other department of the Social Science, while we look at the facts in the concrete, clothed in all the complexity with which Nature has surrounded them, and endeavour to elicit a general law by a process of induction from a comparison of details; there remains no other method than the à priori one, or that of abstract speculation."

22. And that this opinion is no hasty or ill considered one, is evident, because Mr. Mill repeats the very same argument in his later work--"We have thus already come within sight of a conclusion which the progress of the inquiry will, I think, bring before us with the clearest evidence, namely, that in the sciences which deal with phenomena, in which artificial experiments are impossible (as in the case of astronomy), or in which they have a very limited range (as in physiology, mental Philosophy, and the Social Science); induction from direct experience is practised at a disadvantage generally equivalent to impracticability, from 1 Essays upon some unsettled questions in Political Economy, p. 146.

2 Ibid, p. 148.

1

which it follows that the methods in these sciences, in order to accomplish anything worthy of attainment, must be, to a great extent, if not principally, deductive. This is already known to be the case with the first of the sciences we have mentioned, astronomy; that it is not generally recognised as true of the others, is probably one of the reasons why they are still in their infancy." And we must protest against Mr. Mill's doctrine"The deductive method, which in the present state of knowledge is destined henceforth irrevocably to predominate in the cause of scientific investigation. A revolution is peaceably and progressively effecting itself in Philosophy, the reverse of that to which Bacon has attached his name. That great man changed the method of the sciences from deductive to experimental, and it is now rapidly reverting from experimental to deductive." Of this doctrine we shall have something more to say hereafter. 23. Mr. Mill's reason, therefore, for maintaining in exact opposition to what he had done before, that Political Economy is not an Inductive Science, is that it is not possible to perform an unlimited number of experiments in it, as may be done in some physical sciences. The slightest reflection will shew that this argument is quite untenable. It is not possible to perform experiments in Mental Philosophy, yet all the most distinguished cultivators of Psychology in modern times, have unanimously declared it to be an Inductive Science. It is not possible to perform experiments in comparative Philology, and yet, Max Müller strenuously urges that comparative Philology is a physical Inductive Science. And it certainly would be most monstrous to declare that comparative Philology is an à priori science. The power of performing experiments at will is by no means an essential feature of an Inductive Science, though, no doubt, it gives enormous advantages in some cases. It is rarely possible to perform experiments in Geology, yet if any one were to maintain that Geology is an abstract à priori science, few people now-a-days would care to listen to such a person. Mr. Mill's example of astronomy is scarcely relevant, because modern astronomy is undoubtedly founded on induction, and is only a branch of mechanics, which is certainly an Inductive Science. And there are many other sciences to which the preceding remarks are applicable. It is perfectly 1 Logic, B. III., c. 7, § 3. 2 Logic, B. III., c. 13, § 7.

true that in Political Economy it is not generally possible to make experiments, except by those at the head of the State. We may therefore at once admit that a solitary inquirer has not the power of making an unlimited number of arbitrary experiments, and that he can only watch by direct observation those performed by the State, and these will be found to be amply sufficient for the purpose. But in Political Economy and the Moral Sciences generally—we can have what are in all respects equivalent to experiments-namely FEIGNED CASES. It is perfectly well known that when the application of a legal principle is doubtful, it is customary to feign a case, for the purpose of clearing up doubtful points, and the same is true of the Moral Sciences generally, and gave rise to the great Science of CASUISTRY, or Cases of Conscience. We can argue from feigned cases, and educe principles from them with exactly the same degree of certainty as if they were real cases; and also with the same degree of certainty as principles are tested by real experiments in experimental science.

We

24. But there is one point which must be particularly attended to, in arguing from feigned cases, drawn from the very analogy of experiments. The feigned cases devised for the purpose of eliciting principles must be possible. An experiment from its very nature is a possible combination of circumstances. Now in Political Economy, or in any Moral Science, no true principle can be elicited from an impossible case. It is not possible to predicate any result at all in such a case. Nor is this palpable truth of small importance. Writers who have adopted the à priori method have often argued from feigned cases, but they have not always observed this rule. may cite one conspicuous example of the violation of this principle. In some attempts that have been made to show that an increase of the currency can have no effect in increasing the production of wealth, but would only raise the price of existing commodities, it is sometimes argued in this way-"Suppose," it is said, "people were to awake some morning, and find all their money doubled in quantity, what would be the effect? Simply that the prices of all commodities would be doubled." But the answer to this mode of arguing is, that it is an impossible case, and no principle can be educed from such a case. It is not possible that such a thing should happen, and all results

attempted to be deduced from such an example must be discarded as futile. If we would educe principles of any worth from a supposed case of the doubling of the quantity of the currency, we must strictly suppose it to be doubled in the way it would really happen.

25. There are then two great divisions of Inductive Science —Physical and Moral, both absolutely identical in their genius, both to be followed and cultivated by the same method. Now Physical Inductive Science often receives a name from the character of the method by which its general laws, or axioms, are proved, that is by observation and Experiment, and from this it is often called EXPERIMENTAL PHILOSOPHY. Now it seems to be of advantage to have a distinctive name for Moral Inductive Science, or that great branch of Inductive Science, whose axioms are tested by observation and feigned cases, or human Experience, and the name of EXPERIENTIAL PHILOSOPHY seems not inappropriate. Hence we have Inductive Science divided into two great provinces, Physical and Moral, which may be respectively called Experimental and Experiential Philosophy, and then we have this principle-What Experiments are to Experimental Science, possible Feigned Cases are to Experiential Science.

26. As soon as we admit this, it follows that the whole of that great body of Inductive Logic, the foundations of which were so widely and grandly, and securely laid by Bacon, and to which many additions and extensions have been made as new principles of Inductive Logic were evolved in the gradual formation of the various Inductive Sciences, for the purpose of framing conceptions, and testing axioms or general principles, by due experiments, is applicable to frame the conceptions and axioms of Experiential Science by properly devised feigned cases, if experiments cannot be had. Thus we have only to substitute "feigned cases" for "experiments" throughout, and we obtain an Inductive Logic for Experiential Philosophy.

27. Political Economy, or Economics, then, being admitted to be a Physical Science, we have next to inquire what is the nature of a Physical Science, and what are the indispensable methods necessary to be observed to build up and erect a great Inductive Science of Economics on solid and durable foundations?

CHAPTER II.

29

ON THE NATURE OF A PHYSICAL SCIENCE; AND ON THE FORMATION OF GENERAL CONCEPTIONS AND GENERAL AXIOMS.

As it is now generally admitted that Economics is a Physical Science, and is to be constructed in a manner analogous to that in which the various Physical Sciences have been constructed, it will be of advantage to make some general remarks on the nature of a Physical Science, and to lay down some general principles of reasoning which will assist us to decide various controversies in Economics which we shall have to consider.

A Physical Science is the body of laws which govern the phenomena relating to some single idea, or quality, of the most general nature appertaining to material substances; and whatever material quantity possesses that quality is an Element in that science, no matter what other qualities it possesses.

Thus, every substance which possesses divers qualities will be an element in as many sciences as it has qualities. And single qualities may exist in quantities of the most divers natures. It thus happens that in every science there are elements of divers forms and natures.

Thus the science of Arithmetic, or Algebra, is the science of number or measure; and, consequently, whatever can be numbered or measured is an Arithmetical, or Algebraical, Quantity. Thus quantities of the most divers natures are brought under the dominion of Arithmetic or Algebra, simply from their capability of being measured.

Thus time, space, velocity, material substances of all sorts, which have no other property in common but the capability of being measured, are all Arithmetical or Algebraical Quantities.

3. So the Science of Mechanics in its most general form treats of Forces. And these Forces are of the most divers forms and natures, and agree in nothing except that their effects can be measured.