Chapter 13

If indeed every phenomenon was generally the effect of no more than one cause, a knowledge of the law of that cause would, unless there was a logical error in our reasoning, enable us confidently to predict all the circumstances of the phenomenon. We might then, if we had carefully examined our premises and our reasoning, and found no flaw, venture to disbelieve the testimony which might be brought to show that matters had turned out differently from what we should have predicted. If the causes of erroneous conclusions were always patent on the face of the reasonings which lead to them, the human understanding would be a far more trustworthy instrument than it is. But the narrowest examination of the process itself will help us little towards discovering that we have omitted part of the premises which we ought to have taken into our reasoning. Effects are commonly determined by a _concurrence_ of causes. If we have overlooked any one cause, we may reason justly from all the others, and only be the further wrong. Our premises will be true, and our reasoning correct, and yet the result of no value in the particular case. There is, therefore, almost always room for a modest doubt as to our practical conclusions. Against false premises and unsound reasoning, a good mental discipline may effectually secure us; but against the danger of _overlooking_ something, neither strength of understanding nor intellectual cultivation can be more than a very imperfect protection. A person may be warranted in feeling confident, that whatever he has carefully contemplated with his mind's eye he has seen correctly; but no one can be sure that there is not something in existence which he has not seen at all. He can do no more than satisfy himself that he has seen all that is visible to any other persons who have concerned themselves with the subject. For this purpose he must endeavour to place himself at their point of view, and strive earnestly to see the object as they see it; nor give up the attempt until he has either added the appearance which is floating before them to his own stock of realities, or made out clearly that it is an optical deception.

* * * * *

The principles which we have now stated are by no means alien to common apprehension: they are not absolutely hidden, perhaps, from any one, but are commonly seen through a mist. We might have presented the latter part of them in a phraseology in which they would have seemed the most familiar of truisms: we might have cautioned inquirers against too extensive _generalization_, and reminded them that there are _exceptions_ to all rules. Such is the current language of those who distrust comprehensive thinking, without having any clear notion why or where it ought to be distrusted. We have avoided the use of these expressions purposely, because we deem them superficial and inaccurate. The error, when there is error, does _not_ arise from generalizing too extensively; that is, from including too wide a range of particular cases in a single proposition. Doubtless, a man often asserts of an entire class what is only true of a part of it; but his error generally consists not in making too wide an assertion, but in making the wrong _kind_ of assertion: he predicated an actual result, when he should only have predicated a _tendency_ to that result--a power acting with a certain intensity in that direction. With regard to _exceptions_; in any tolerably ably advanced science there is properly no such thing as an exception. What is thought to be an exception to a principle is always some other and distinct principle cutting into the former: some other force which impinges against the first force, and deflects it from its direction. There are not a _law_ and an _exception_ to that law--the law acting in ninety-nine cases, and the exception in one. There are two laws, each possibly acting in the whole hundred cases, and bringing about a common effect by their conjunct operation. If the force which, being the less conspicuous of the two, is called the disturbing force, prevails sufficiently over the other force in some one case, to constitute that case what is commonly called an exception, the same disturbing force probably acts as a modifying cause in many other cases which no one will call exceptions.

Thus if it were stated to be a law of nature, that all heavy bodies fall to the ground, it would probably be said that the resistance of the atmosphere, which prevents a balloon from falling, constitutes the balloon an exception to that pretended law of nature. But the real law is, that all heavy bodies _tend_ to fall; and to this there is no exception, not even the sun and moon; for even they, as every astronomer knows, tend towards the earth, with a force exactly equal to that with which the earth tends towards them. The resistance of the atmosphere might, in the particular case of the balloon, from a misapprehension of what the law of gravitation is, be said to _prevail_ over the law; but its disturbing effect is quite as real in every other case, since though it does not prevent, it retards the fall of all bodies whatever. The rule, and the so-called exception, do not divide the cases between them; each of them is a comprehensive rule extending to all cases. To call one of these concurrent principles an exception to the other, is superficial, and contrary to the correct principles of nomenclature and arrangement. An effect of precisely the same kind, and arising from the same cause, ought not to be placed in two different categories, merely as there does or does not exist another cause preponderating over it.

It is only in art, as distinguished from science, that we can with propriety speak of exceptions. Art, the immediate end of which is practice, has nothing to do with causes, except as the means of bringing about effects. However heterogeneous the causes, it carries the effects of them all into one single reckoning, and according as the sum-total is _plus_ or _minus_, according as it falls above or below a certain line, Art says, Do this, or Abstain from doing it. The exception does not run by insensible degrees into the rule, like what are called exceptions in science. In a question of practice it frequently happens that a certain thing is either fit to be done, or fit to be altogether abstained from, there being no medium. If, in the majority of cases, it is fit to be done, that is made the rule. When a case subsequently occurs in which the thing ought not to be done, an entirely new leaf is turned over; the rule is now done with, and dismissed: a new train of ideas is introduced, between which and those involved in the rule there is a broad line of demarcation; as broad and _tranchant_ as the difference between Ay and No. Very possibly, between the last case which comes within the rule and the first of the exception, there is only the difference of a shade: but that shade probably makes the whole interval between acting in one way and in a totally different one. We may, therefore, in talking of art, unobjectionably speak of the _rule_ and the _exception_; meaning by the rule, the cases in which there exists a preponderance, however slight, of inducements for acting in a particular way; and by the exception, the cases in which the preponderance is on the contrary side.

THE END.

NOTES:

[8] We say, the _production_ and _distribution_, not, as is usual with writers on this science, the production, distribution, and _consumption_. For we contend that Political Economy, as conceived by those very writers, has nothing to do with the consumption of wealth, further than as the consideration of it is inseparable from that of production, or from that of distribution. We know not of any _laws_ of the _consumption_ of wealth as the subject of a distinct science: they can be no other than the laws of human enjoyment. Political economists have never treated of consumption on its own account, but always for the purpose of the inquiry in what manner different kinds of consumption affect the production and distribution of wealth. Under the head of Consumption, in professed treatises on the science, the following are the subjects treated of: 1st, The distinction between _productive_ and _unproductive_ consumption; 2nd, The inquiry whether it is possible for _too much_ wealth to be _produced_, and for too great a portion of what has been produced to be applied to the purpose of further _production_; 3rd, The theory of taxation, that is to say, the following two questions--by whom each particular tax is paid (a question of _distribution_), and in what manner particular taxes affect _production_.

[9] The physical laws of the production of useful objects are all equally presupposed by the science of Political Economy: most of them, however, it presupposes in the gross, seeming to say nothing about them. A few (such, for instance, as the decreasing ratio in which the produce of the soil is increased by an increased application of labour) it is obliged particularly to specify, and thus seems to borrow those truths from the physical sciences to which they properly belong, and include them among its own.

[10] The _science_ of legislation is an incorrect and misleading expression. Legislation is _making laws_. We do not talk of the _science_ of _making_ anything. Even the _science of government_ would be an objectionable expression, were it not that _government_ is often loosely taken to signify, not the act of governing, but the state or condition of _being governed_, or of living under a government. A preferable expression would be, the science of _political society_; a principal branch of the more extensive science of society, characterized in the text.

[11] One of the strongest reasons for drawing the line of separation clearly and broadly between science and art is the following:--That the principle of classification in science most conveniently follows the classification of _causes_, while arts must necessarily be classified according to the classification of the _effects_, the production of which is their appropriate end. Now an effect, whether in physics or morals, commonly depends upon a concurrence of causes, and it frequently happens that several of these causes belong to different sciences. Thus in the construction of engines upon the principles of the science of _mechanics_, it is necessary to bear in mind the _chemical_ properties of the material, such as its liability to oxydize; its electrical and magnetic properties, and so forth. From this it follows that although the necessary foundation of all art is science, that is, the knowledge of the properties or laws of the objects upon which, and with which, the art dons its work; it is not equally true that every art corresponds to one particular science. Each art presupposes, not one science, but science in general; or, at least, many distinct sciences.

(Editor's note:)

Essays on some Unsettled Questions of Political Economy

These five essays represent Mill's earliest thoughts on economic matters and were first composed in 1829 and 1830 before his reputation had been established by the publication of _Logic_ in 1843. Their successful reception no doubt hastened the composition of his comprehensive work the _Principles of Political Economy_ (1848).