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"as experience concerned, have been hitherto administered."Nothing is to be found which has been duly investigated; nothing "which has been verified by a careful examination of proofs; "nothing which has been reduced to the standard of number, "weight, or measure.”*
This very important aphorism deserves the serious attention of those who, while they are perpetually declaiming against the uncertainty and fallacy of systems, are themselves employed in amassing a chaos of insulated particulars, which they admit upon the slenderest evidence. Such ih, sensible of their own incapacity for scientific investigation, have often a malicious pleasure in destroying the fabrics of their predecessors; or, if they should be actuated by less unworthy motives, they may yet feel a certain gratification to their vanity, in astonishing the world with anomalous and unlooked for phenomena;—a weakness which results not less naturally from ignorance and folly, than a bias to premature generalization from the consciousness of genius.-Both of these weaknesses are undoubtedly adverse to the progress of science; but, in the actual state of human knowledge, the former is perhaps the more dangerous of the two.
In the practice of medicine (to which topic I wish to confine myself more particularly at present) there are a variety of other circumstances, which, abstracting from any suspicion of bad faith in those on whose testimony the credibility of facts depends, have a tendency to vitiate the most candid accounts of what is commonly dignified with the title of experience. So deeply rooted in the constitution of the mind is that disposition on which philosophy is grafted, that the simplest narrative of the most illiterate observer involves more or less of hypothesis; nay, in general, it will be found, that, in proportion to his ignorance, the greater is the number of conjectural principles involved in his statements.
A village-apothecary (and, if possible, in a still greater degree, an experienced nurse) is seldom able to describe the plainest case, without employing a phraseology of which every word is a theory; whereas a simple and genuine specification of the phenomena which mark a particular disease;—a specification unsophisticated by fancy, or by preconceived opinions, may be regarded as unequivocal evidence of a mind trained by long and successful study to the most difficult of all arts, that of the faithful interpretation of nature.
Independently, however, of all these circumstances, which tend. so powerfully to vitiate the data whence the physician has to reason; and supposing his assumed facts to be stated, not only with the most scrupulous regard to truth, but with the most jealous exclusion of theoretical expressions, still the evidence upon which he proceeds is, at best, conjectural and dubious, when compared with what is required in chemistry or in mechanics. It is seldom, if ever, possible, that the description of any medical case can include all the
» Nov. Org. Lib. I. Aph. xcviii.
circumstances with which the result was connected; and, therefore, how true soever the facts described may be, yet, when the conclusion to which they lead comes to be applied as a general rule in practice, it is not only a le rashly drawn from one single experiment, but a rule transferred from a case imperfectly known, to another of which we are equally ignorant. Here, too, it will be found, that the evidence of experience is incomparably less in favour of the empiric, than of the cautious theorist; or rather, that it is by cautious theory alone, that experience can be rendered of any value. Nothing, indeed, can be more absurd man to contrast, as is commonly done, experience with theory, as if they stood in opposition to each other. Without theory, (or, in other words, without general principles, inferred from a sagacious comparison of a variety of phenomena,) experience is a blind and useless guide; while, on the other hand, a legitimate theory (and the same observation may be extended to hypothetical theories, supported by numerous analogies,) necessarily presupposes a knowledge of connected and well ascertained facts, more comprehensive, by far, than any mere empiric is likely to possess. When a scientific practitioner, accordingly, quits the empirical routine of his profession, in quest of a higher and more commanding ground, he does not proceed on the supposition that it is possible to supersede the necessity of experience by the most accurate reasonings a priori; but, distrusting conclusions which rest on the observation of this or that individual, he is anxious, by combining hose of an immense multitude, to separate incidental conjunctions from established connexions, and to ascertain those laws of the human frame which rest on the universal experience of mankind. The idea of following nature in the treatment of diseases; an idea which, I believe, prevails more and more in the practice of every physician, in proportion as his views are enlarged by science, is founded, not on hypothesis, but on one of the most general laws yet known with respect to the animal economy; and it implies an acknowledgment, not only of the vanity of abstract theories, but of the limited province of human art.*
*" (laudet corpus vi prorsus mirabili, qua contra morhos se tueatur; multos arceat; multos jam inchoatos quam optime et citissime solvat; aliosque, suo modo, ad felicem exitum lentius perducat.
"Haec, Autocrateia vis Naturae medicatrix vocatur; medicis, philosophis, notissima, et jure celeberrima. Haec sola ad multos morbos sanandos sufficit, in omnibus fere prodest: Quin et medicamenta sua natura optima, tantum solummodo prosunt, quantum hujus vires insitas excitent, dirigant, gubernent. Medicina enim neque agit in cadaver, neque repug. Dante natura aliquid proficit."
Conspectus Medicinae Theoreticae. Auctore Jacobo Gregory, M. D. 59, 60. (Edin 1732.)†
+ [The body happily possesses a power truly admirable, by means of which it protects itself against diseases. Many it repels; many already contracted it safely and speedily dissipates; and others, in its own way, it brings more slowly to a happy issue.
This is called the innate remedial power of nature: by physicians and philosophers well known, and justly esteemed most admirable. Of itself it suffices to cure many diseases, and in almost all is beneficial. Moreover, medicines in their nature the most valuable, profit only as they excite, direct and regulate the power of this principle. For medicine neither acts upon the dead body, nor when nature is averse, can be of any benefit. Gre gory's Conspectus Med. Theoret. Edin. 1782, sections 59 and 60.]
These slight remarks are sufficient to show, how vague and indeterminate the notion is, which is commonly annexed to the word experience by the most zealous advocates for its paramount authority in medicine. They seem farther to shew, that the question between them and their adversaries amounts to little more than a dispute about the comparative advantages of an experience guided by penetration and judgment, or of an experience which is to supersede all exercise of our rational faculties; of an experience accurate, various and discriminating, or of one which is gross and undistinguishing, like the perceptions of the lower animals.
Another department of knowledge in which constant appeals are made to experience, is the science of politics; and, in this science also, I apprehend, as well as in the former, that word is used with a far greater degree of latitude than is generally suspected. Indeed, most of the remarks which have been already offered on the one subject may be extended (mutatis mutandis) to the other. I shall confine my attention, therefore, in what follows, to one or two peculiarities by which politics is specifically and exclusively characterized as an object of study, and which seem to remove the species of evidence it admits of, to a still greater distance than that of medicine itself, from what the word experience naturally suggests to a careless inquirer.
The science of politics may be divided into two parts; the first having for its object the theory of government; the second, the general principles of legislation. That I may not lose myself in too wide a field, I shall, on the present occasion, wave all consideration of the former; and, for the sake of still greater precision, shall restrict my remarks to those branches of the latter, which are comprehended under the general title of Political Economy;-a phrase, however, which I wish to be here understood in its most extensive meaning.*
They who have turned their attention, during the last century, to inquiries connected with population, national wealth, and other collateral subjects, may be divided into two classes; to the one of which we may, for the sake of distinction, give the title of political arithmeticians, or statistical collectors; to the other, that of political economists, or political philosophers. The former are generally supposed to have the evidence of experience in their favour, and seldom fail to arrogate to themselves exclusively, the merit of treading closely in the footsteps of Bacon. In comparison with them, the latter are considered as little better than visionaries, or, at least, as entitled to no credit whatever, when their conclusions are at variance with the details of statistics.
In opposition to this prevailing prejudice it may, with confidence, be asserted, that, in so far as either of these branches of knowledge has any real value, it must rest on a basis of well-ascertained facts; and that the difference between them consists only in the different
* See note (Z.)
nature of the facts with which they are respectively conversant. The facts accumulated by the statistical collector are merely particular results, which other men have seldom an opportunity of verifying or of disproving; and which, to those who consider them in an insulated state, can never afford any important information. The facts, which the political philosopher professes to investigate, are exposed to the examination of all mankind; and while they enable him, like the general laws of physics, to ascertain numberless particulars by synthetic reasoning, they furnish the means of estimating the credibility of evidence resting on the testimony of individual observers.
It is acknowledged by Mr. Smith with respect to himself, that he had "no great faith in political arithmetic;"* and I agree with him so far as to think that little, if any, regard is due to a particular phenomenon, when stated as an objection to a conclusion resting on the general laws which regulate the course of human affairs. Even admitting the phenomenon in question to have been accurately observed, and faithfully described, it is yet possible that we may be imperfectly acquainted with that combination of circumstances whereby the effect is modified; and that, if these circumstances were fully before us, this apparent exception would turn out an additional illustration of the very truth which it was brought to invalidate.
If these observations be just, instead of appealing to political arithmetic as a check on the conclusions of political economy, it would often be more reasonable to have recourse to political economy as a check on the extravagancies of political arithmetic. Nor will this assertion appear paradoxical to those who consider, that the object of the political arithmetician is too frequently to record apparent exceptions to rules sanctioned by the general experience of mankind; and, consequently, that in cases where there is an obvious or a demonstrative incompatibility between the alleged exception and the general principle, the fair logical inference is not against the truth of the latter, but against the possibility of the former.
If has long been an established opinion among the most judicious and enlightened philosophers, that as the desire of bettering our condition appears equally from a careful review of the motives which habitually influence our own conduct, and from a general survey of the history of our species, to be the masterspring of human industry, the labour of slaves never can be so productive as that of freemen. Not many years have elapsed, since it was customary to stigmatize this reasoning as visionary and metaphysical; and to oppose to it that species of evidence to which we were often reminded that all theories must bend;-the evidence of experimental calculations, furnished by intelligent and credible observers on the other side of the Atlantic. An accurate examination of the fact has shewn how
* Wealth of Nations, Vol. II. p. 310. 9th edit,
wide of the truth these calculations were ;-but independently of any such detection of their fallacy, might it not have been justly affirmed, that the argument from experi nce was decidedly against their credibility-the facts, appealed to, resting solely upon the good sense and good faith of individual witnesses; while the opposite argument, drawn from the principles of the human frame, was supported by the united voice of all nations and ages?
If we examine the leading principles which run through Mr. Smith's Inquiry into the Nature and Causes of the Wealth of Nations, we shall find, that all of them are general facts or general results, analogous to that which has been just mentioned. Of this kind, for instance, are the following propositions,--from which a very large proportion of his characteristical doctrines follow, as necessary and almost manifest corollaries: That what we call the Political Order, is much less the effect of human contrivance than is commonly imagined;--That every man is a better judge of his own interest than any legislator can be for him; and that this regard to private interest (or, in other words, this desire of bettering our con dition) may be safely trusted to as a principle of action universal among men in its operation;-a principle stronger, indeed, in some than in others, but constant in its habitual influence upon all:-That, where the rights of individuals are completely protected by the magistrate, there is a strong tendency in human affairs, arising from what we are apt to consider as the selfish passions of our nature, to a progressive and rapid improvement in the state of society :-That this tendency to improvement in human affairs is often so very pow erful, as to correct the inconveniences threatened by the errours of the statesman :-And that, therefore, the reasonable presumption is in favour of every measure which is calculated to afford to its farther development, a scope still freer than what it at present enjoys; or, which amounts very nearly to the same thing, in favour of as great a liberty in the employment of industry, of capital and of talents, as is consistent with the security of property, and of the other rights of our fellow-citizens-The premises it is perfectly obvious, from which these conclusions are deduced, are neither hypothetical assumptions, nor metaphysical abstractions. They are practical maxims of good sense, approved by the experience of men in all ages of the world; and of which, if we wish for any additional confirmations, we have only to retire within our own bosoms, or to open our eyes on what is passing around us.
From these considerations it would appear, that in politics, as well as in many of the other sciences, the loudest advocates for experience are the least entitled to appeal to its authority in favour of their dogmas; and that the charge of a presumptuous confidence in human wisdom and foresight, which they are perpetually urging against political philosophers, may, with far greater justice, be retorted on themselves. An additional illustration of this is presented by the strikingly contrasted effects of statistical and of philosophi cal studies on the intellectual habits in general; the former invaria