Physician and patient

by Worthington Hooker

All real knowledge is based upon observation; and it is the facts discovered by observation, which, accumulating from age to age, constitute the store of human knowledge. Not a single grain has ever been added to this store, in all the ages of the world, through the instrumentality of theory alone. Theory, or hypothesis, has often suggested the existence of facts, and has directed in the pursuit after them, but observation after all is the only agent that has discovered them.

Facts are of two kinds—particular and general. General facts are discovered by a careful observation of a great number of particular facts. Thus Newton, by observing many particular or individual facts, established the general fact, which is called gravitation, viz., that all bodies are attracted towards each other, or have a tendency to come together. So in medical science, by an observation of many facts in individual cases, it has been discovered, that there is a tendency in the human system to restoration to health, whenever it is attacked with disease—a tendency, existing as a general fact, to which has been given the name, vis medicatrix naturæ.

These general facts are sometimes termed principles or laws, and are sometimes spoken of as the relationships of facts. A theory, or hypothesis, consists in a supposition of relationships which have not yet been ascertained. Thus Newton, after discovering the great general fact of gravitation, supposed that there might be a sort of ether connecting bodies together, and acting as the medium of their attraction. This supposition of a relationship, or general fact, not yet ascertained, is a theory or hypothesis. So when Stahl supposed the principle called the vis medicatrix naturæ to be in the soul, and when Cullen supposed that it exists in the nerves and produces in fever a spasm of the extreme vessels, they both put forth a mere theory. Cullen speaks of Stahl’s theory as being fanciful. It is so. But Cullen’s is just as fanciful, if by this word it is meant that it is unsubstantiated by fact. Cullen’s supposition is more plausible, it is true, than Stahl’s; but it is no nearer being a proved fact.

There is often much indefiniteness in the use of the word theory. Thus the doctrine, or law of gravitation, as discovered by Newton is sometimes spoken of as his theory of gravitation. It was once his theory; that is, when it was a mere supposition in his mind. But when, by a series of observations it came to be a proved fact, it was no longer a theory. So the laws of the circulation of the blood, as discovered by Harvey, are sometimes erroneously spoken of as his theory of the circulation.

Some theories are said to be founded on facts, while others are deemed to be very fanciful. But theory can never be said, strictly speaking, to be founded on facts. It has relation to facts, it is true, but in the attempt to explain their nature, it goes beyond them over into the domain of conjecture.

Every one who puts forth a theory, is apt to think that all previous theories are false, while his is proved to be conformable to facts. Dr. Cullen, in announcing his theory, or doctrine (as he styles it) of fever, which is from beginning to end a series of unproved assertions, says, “I flatter myself that I have avoided hypothesis, and what have been called theories.” So Dr. Rush, after framing a theory even more palpably fanciful, says, that he conceives the doctrine of fever that he has aimed to establish rests upon facts only.

There is no science, in which there has been so much theorizing, as there has been in that of medicine. Its history seems to be almost altogether a history of untenable theories. These theories are at least the prominent objects that present themselves to view. Every period has had its favorite theory, which has exerted its influence upon the general medical mind. Almost every great name in medical history is associated with some celebrated hypothesis. And it would seem that sometimes the attention of the whole profession has been almost exclusively directed to the strife between the advocates of opposing theories. This overweening attachment to theories has been a very great obstacle to the advancement of medicine as a science. It has turned the medical mind away from the legitimate pathway of discovery, and the strict observation of facts has been neglected in the contemplation of mere fancies.

It is true of medicine, as it is of every other science, that every advance which has been made has been effected by observation, and by observation alone. It is the good observer, and not the mere ingenious theorizer, who has made these advances. And if the theorizer has added anything to the store of knowledge, it is only when he has come down from his airy flight of fancy to the drudgery of humble common observation. He has for the time forgotten his favorite theory, and has subjected hypothesis to its proper subserviency to observation, in suggesting the points to which that observation may be directed. It is in this way, and in this alone, that many of the authors of theories, escaping occasionally from the domination of a theorizing spirit, have added rich treasures to the storehouse of medical science. Even before the discovery of the circulation of the blood, though medical theories necessarily contained many absurdities, yet many of their advocates were acute and accurate observers; and their facts are valuable, though the theories, which they framed to account for these facts, may appear to us even ridiculous. They collected a great amount of good materials; but instead of erecting with them a structure full of beauty and symmetry, capable of resisting the commotions of ages, they reared a motley pile which easily tumbled into ruins. They were men of the most persevering industry. They seemed to forget entirely that “of making many books there is no end; and much study is a weariness of the flesh.” Quartos and folios were produced in abundance, full of mixtures of wisdom and folly, as incongruous as were some of the old prescriptions with their hundred or more ingredients. And as some of the articles, which composed these hundred-headed enemies of disease, are now among our most valuable remedies, so there are portions of those strange compounds of fact and speculation, which will always stand as monuments of genius and industry. They are among the principles which form the basis of medicine. The student, as he now reads the older works in medical science, regards but as matters of curiosity the theories of lentor and viscosity, acrimony, &c.; and picks out from the mass of rubbish the pearls and precious stones, which are almost concealed beneath it.

The reader cannot fail to have seen, in the course of my remarks, what I deem to be the province of theory, or hypothesis. It is simply suggestive. This is its true vocation. It establishes no fact, and no principle. It should be the mere handmaid of observation, and should be kept in perfect subjection to her control. It never should be a rival, much less should it have supremacy, as it has too often done, in the domains of science.

Thus restricted to its proper sphere, theory is of essential service in extending the boundaries of science. It often suggests the line of discovery. It constantly reaches beyond present knowledge. We theorize, that is, we suppose; then by observation we discover. If we find our hypothesis or supposition to be correct, we discover a positive fact. If we find it not to be, we discover a negative fact, and not valueless because negative—some of our negative facts are worth quite as much as positive ones.