ONE General Theory at the basis of all phenomena. In particular classes of cases, there may undoubtedly be other circumstances which may aggravate, neutralize, or overpower, and seemingly reverse the General Theory; but for all that, it is there, and acts universally. In several different sciences no doubt different General Theories have prevailed, such as in Astronomy, Optics, Heat, Electricity, &c.; but no Physical Philosopher ever dreamt of explaining every different class of phenomena by a distinct theory. No one ever thought of writing a book on Astronomy, in which one chapter was written on the Ptolemaic Theory, another chapter on the Copernican Theory, and another chapter on Tycho Brahe's Theory. No one ever thought of writing a book on Optics, one part of which was based upon the Emission Theory, and another on the Wave Theory of Light, and so on of the other sciences. It has always been clearly understood that there could be but ONE General Theory which governed all phenomena, though liable to be modified by disturbing causes in particular cases. And the business of the Physical Philosopher has always been to discover which is the true General Theory; and the grand business of the Baconian, or Inductive, Logic, has been to discover and lay down the principles which are to decide which is the true Theory. In politics, no doubt, we require the spirit of compromise, and many contradictions are tolerated for the sake of general peace. But in science, toleration and compromise are impossible. It is always a mortal combat between rival theories. All but one must perish; and it is the business of Inductive Logic to pronounce the doom of Life or Death.

Now without even yet determining what Economics is, we may lay this down, that if it be a Physical Science, as is so often asserted, there can be but ONE General Theory of the relations between Economic Quantities. To break up

Economic phenomena into distinct classes of cases, and to maintain that there is a distinct fundamental Theory, or Axiom, or Law, governing each class of cases, would be utterly abhorrent to the fundamental principles of Natural Philosophy.

Bacon gives abundant precepts for the determination of the truth of rival theories, and he enforces the necessity of carefully devised experiments (and in the Moral Sciences possible feigned

cases), and the attention necessary to contrive a variety of them, and to extend the inquiry generally. "For no one successfully investigates the nature of a thing in the thing itself." And he advises us to imitate the Divine Wisdom, which in the first day created light only. So we must endeavour to gather from all sorts of experience, and to discover true causes and general principles, and to devise "experimenta lucifera" for this purpose, or instances contrived with the express view of testing general principles before we go to practice. For he says that all true knowledge consists in knowing true causes, and that which in Theory is the cause, in Practice is the rule. "For though we are chiefly in pursuit of the practical and active part of science, we must wait for the time of the harvest, and not reap the moss or the green corn. For we well know that general principles once rightly discovered, will carry whole troops of works with them, and will produce effects not in single instances, but in multitudes." 1

Some writers of eminence, indeed, seem to think that Bacon has neglected too much, or even omitted, the deductive part of science, or the explanation of phenomena by general principles. But we cannot agree to this. He has clearly and repeatedly asserted that his Philosophy consists, first, of the eliciting general conceptions and general axioms from particular cases -the Inductive part-the ascending to abstract principles from concrete cases; and, secondly, the descending part, or the application of general principles, so obtained by Induction, to the explanation of phenomena. "Axioms duly and orderly formed from particulars, easily discover the way to new particulars, and thus render sciences active.""The true method of experience, on the contrary, first lights the candle, and then by means of the candle shews the way; commencing as it does with experience duly ordered and digested, not bungling or erratic, and from it educing Axioms, and from established Axioms again new experiments." "From the new light of Axioms, which, having been educed from these particulars by a certain method and rule, shall in their turn point out the way again to new particulars, greater things may be looked for. For our road does not lie on a level, but ascends and descends; first ascending to Axioms, 1 Distributio Operis. 2 Nov. Org., B. 1., Ap. 24. 3 Nov. Org., B. 1., 84.

3

then descending to works."- "And the truth is that the knowledge of simple natures well examined and defined is light; it gives entrance to all the secrets of nature's workshop, and virtually includes and draws after it whole bands and troops of works, and opens to us the source of the noblest axioms."

2

It clearly appears, therefore, that Deduction was not only an essential part of the Baconian Philosophy, but its very aim and object, because it was the practical part of it. The very aim of Bacon was, by discovering true science or the knowledge of causes, to be able to govern the world of reality, or effects. To say, therefore, that Bacon omitted the Deductive part is manifestly as great an error as that of J. B. Say, who declared that Bacon was quite ignorant that the method of his Philosophy was applicable to anything but Physical Science. Mr. Mill is, therefore, also in error when he says that a revolution in science is peaceably taking place, and that we are reverting from the Inductive to the Deductive method. Even if it were true, it is not a revolt from, but the express fulfilment of, the Baconian Philosophy. And we think the example Mr. Mill has selected peculiarly unfortunate, because the practical triumphs of the astronomer are entirely due to the Theoretical, or Inductive, discovery of the fundamental Laws of Mechanics. Astronomy is nothing whatever but a practical example of the general laws of Mechanics, and is the most sublime proof of the truth of the Baconian Philosophy.

19. One of the great fundamental Laws of Inductive Logic pervading every part of the Novum Organum, and expressing its very spirit, is called the Law of Continuity, and is thus described by Whewell, Nov. Org. Renov., p. 221:—

"A quantity cannot pass from one amount to another by any change of conditions, without passing through all the intermediate magnitudes, according to the intermediate conditions."

This Law may often be employed to correct inaccurate deductions, and to reject distinctions which have no real foundation in nature. For example: The Aristotelians made a distinction between motion according to nature (as that of a body falling vertically downwards) and motion contrary to nature (as that of a body moving along a horizontal plane); the former they held became naturally quicker and quicker, the latter naturally slower 1 Nov. Org., B. I., Ap., 103. 2 Nov. Org., B. I., Ap., 121.

and slower. But to this it might be replied that a horizontal line may pass by gradual motion through various inclined positions to a vertical position, and thus the retarded motion may pass into the accelerated; and hence there must be some inclined plane on which motion is naturally uniform, which is false, and therefore the distinction of such kinds of motion is unfounded." That is to say, there is no point whatever at which one kind of motion passes into another. Again:-"The evidence of the Law of Continuity resides in the universality of those Ideas, which enter into our apprehension of Laws of Nature. When of two quantities one depends upon the other, the Law of Continuity necessarily governs the dependence. Every philosopher has the power of applying this Law in proportion as he has the faculty of apprehending the Ideas which he employs in his Induction, with the same clearness and steadiness which belong to the fundamental Ideas of Quantity, Space, and Number. To those who possess this faculty, the Law is a rule of very wide and decisive application. Its use, as has appeared in the above example, is seen rather in the disproof of erroneous views, and in the correction of false propositions, than in the invention of new truths. It is a test of truth rather than an instrument of discovery "—which, we may observe, is the true function of all Logic, both Aristotelian and Baconian-formal and inductive.

The Law of Continuity is one of the most powerful weapons of Inductive Logic, and is of very wide application in Physical research. It has been employed with immense effect in settling the fundamental conceptions of Mechanics, Electricity, Geology, and indeed of every other science. Its capability of being applied to settle the fundamental Conceptions and Axioms of Economics has never yet, that we are aware of, even been suspected! And yet we shall shew that it is capable of absolutely deciding and determining once and for ever, the greater portion of the controversies in Economics.

The great philosophers who founded the Physical Sciences instinctively obeyed the Laws of the Baconian, or Inductive, Logic, which are undoubtedly true in the main. In fact this Logic, must have been necessarily evolved in the process of the formation of those sciences. Because in all controversies it is necessarily assumed that there is some supreme power 1 Whewell, Nov. Org., Renov., p. 223.

which is admitted to be capable of deciding authoritatively on all scientific discussions, which must be yielded to by both parties, or else there is no prospect or possibility of bringing the discussions to a final end. And that supreme power is the REASON, the Divine AOгOΣ, or LOGIC-the common property of GoD and MAN.'

"Know that in the soul

Are many lesser faculties that serve
REASON as chief; among these Fancy next
Her office holds; of all external things,
Which the five watchful senses represent,
She forms imaginations, aery shapes,
Which Reason, joining or disjoining, frames
All what we affirm or what deny, and call
Our knowledge or opinion; then retires
Into her private cell, when Nature rests.
Oft in her absence mimic Fancy wakes
To imitate her; but, misjoining shapes,
Wild work produces oft-

Ill matching words and deeds."

The wonderful sagacity of Bacon was that he anticipated this natural process, and first created that science of sciences, which rules every particular science with supreme power. All controversies in Economics both as to Conceptions and Axioms must be brought to the tribunal of this supreme power, and must be decided by exactly the same general principles of Inductive Logic, as have already decided finally the controversies in Physical Science.

20. We shall endeavour in the next three chapters to shew the application of the principles we have been considering. In the first place we shall give a narrative of the differences of opinion, or a History of the Ideas that have prevailed as to the nature and limits of the science of Economics itself, and employ the principles of Inductive Logic to determine which is the true one. We shall frame a Definition, or precise Conception of the Science, clearly expressing the body of phenomena, whose laws it is our business to discover.

The next chapter investigates the Fundamental Conceptions of the Science, and brings together various controversies and discussions which have been held on each of them, and 1 Cicero De legibus, B. I., § 5.