History of Civilization in England, Vol. 3 of 3

To generalize such irregularities, or, in other words, to show that they are not irregularities at all, was the main object of Hunter's life, and was the noblest part of his mission. Hence, notwithstanding his vast achievements in physiology, his favourite pursuit was pathology,888 where, the phenomena being more complex, the intellect has more play. In this great field, he studied the aberrations of structure and of function, in the vegetable, as well as in the animal, world;889 while, for the aberrations of form, which are the external manifestations of disturbed structure, he took into consideration the appearances presented by the mineral kingdom. There, the power of crystallization is the leading feature, and there, violations of symmetry constitute the essential disorder, whether the deformity of the crystal is subsequent to its production, or whether, being the result of what happened before its production, it is an original, and, if we may so say, congenital, defect. In either case, it is a deviation from the normal type, and, as such, is analogous to the monstrosities, both of animals and of vegetables.890 The mind of Hunter, by sweeping through this immense range of thought, attained to such commanding views of the philosophy of disease, that, in that department, he is certainly without a rival. As a physiologist, he was equalled, or perhaps excelled, by Aristotle; but as a pathologist, he stands alone, if we consider what pathology was when he found it, and what it was when he left it.891 Since his death, the rapid advance of morbid anatomy and of chemistry has caused some of his doctrines to be modified, and some of them to be overturned. This has been the work of inferior men, wielding superior chemical and microscopical resources. To say that the successors of John Hunter are inferior to him, is no disparagement to their abilities, since he was one of those extremely rare characters who only appear at very long intervals, and who, when they do appear, remodel the fabric of knowledge. They revolutionize our modes of thought; they stir up the intellect to insurrection; they are the rebels and demagogues of science. And though the pathologists of the nineteenth century have chosen a humbler path, this must not blind us to their merits, or prevent us from being grateful for what they have done. We cannot, however, be too often reminded, that the really great men, and those who are the sole permanent benefactors of their species, are not the great experimenters, nor the great observers, nor the great readers, nor the great scholars, but the great thinkers. Thought is the creator and vivifier of all human affairs. Actions, facts, and external manifestations of every kind, often triumph for a while; but it is the progress of ideas which ultimately determines the progress of the world. Unless these are changed, every other change is superficial, and every improvement is precarious. It is, however, evident that, in the present state of our knowledge, all ideas respecting nature must refer either to the normal or to the abnormal; that is to say, they must be concerned either with what is regular, uniform, and obedient to recognized principles, or else with what is irregular, perturbed, and disobedient. Of these two divisions, the first belongs to science; the second, to superstition. John Hunter formed the superb conception of merging both classes of ideas into one, by showing that nothing is irregular, that nothing is perturbed, that nothing is disobedient. Centuries, perhaps, may elapse before that conception will be consummated. But what Hunter effected towards it, places him at the head of all pathologists, ancient or modern. For, with him, the science of pathology did not mean the laws of disease in man alone, or even in all animals, or even in the whole organic kingdom; but it meant the laws of disease and of malformation in the entire material world, organic and inorganic. His great object was, to raise a science of the abnormal. He determined to contemplate nature as a vast and united whole, exhibiting, indeed, at different times different appearances, but preserving, amidst every change, a principle of uniform and uninterrupted order, admitting of no deviation, undergoing no disturbance, and presenting no real irregularity, albeit to the common eye, irregularities abound on every side.

As pathology was the science to which Hunter was most devoted, so also was it that in which his natural love of deduction was most apparent. Here, far more than in his physiological inquiries, do we find a desire to multiply original principles from which he could reason; in opposition to the inductive method, which always aims at diminishing these principles by gradual and successive analysis. Thus, for instance, in his animal pathology, he attempted to introduce, as an ultimate principle from which he could argue, the idea that all diseases move more rapidly towards the skin than towards internal parts, by virtue of some hidden force, which also obliges vegetables to approach the surface of the earth.892 Another favourite proposition, which he often used as a major premiss, and by its aid constructed deductively a pathological argument, was, that in no substance, be it what it may, can two processes go on in the same part at the same time.893 By applying this universal proposition to the more limited phenomena of animal life, he inferred that two general diseases cannot co-exist in the same individual; and he relied so much on this ratiocination, that he refused to credit any testimony by which it was impugned.894 There is reason to believe that his conclusion is erroneous, and that different diseases can so accompany each other, as to be united in the same individual, at the same time, and in the same part.895 Whether or not this be the case, it is equally interesting to notice the process of thought which led Hunter to bestow infinitely more pains in arguing from the general theory, than in arguing to it. Indeed, he can hardly be said to have argued to it at all, since he obtained it by a rough and hasty generalization from what seemed to be the obvious properties of inorganic matter. Having thus obtained it, he applied it to the pathological phenomena of the organic world, and especially of the animal world. That he should have adopted this course, is a curious proof of the energy of his deductive habits, and of the force of mind which enabled him so to set at naught the traditions of his English contemporaries, as to follow a method which, in the opinion of every one who surrounded him, was not only full of danger, but could never lead to truth.

Other parts of his pathology abound with similar instances, which show how anxious he was to assume principles on which he could build arguments. Of this kind were his ideas respecting sympathy, as connected with action. He suggested, that the simplest forms of sympathy would probably be found in the vegetable world, because there, the general arrangements are less intricate than in the animal world.896 On this supposition, he constructed a series of curious and refined speculations, of which, however, I must confine myself to giving a very short summary. As animals sympathize more than vegetables, this helps us to understand why it is that their movements are more numerous. For, sympathy, being a susceptibility to impression, is also a principle of action.897 Like other principles of action, it may be either natural or diseased.898 But, whichever it be, it can, in plants, have only one mode of development, because, in them, it can only be influenced by stimulus; while in animals, which have sensation, it has necessarily three modes, one from stimulus, one from sensation, and a third compounded of the other two.899 These are the largest divisions of sympathy, if we consider the organic world as a whole. In single cases, however, sympathy admits of still further subdivision. We may reason from it, in reference to the age of the individual;900 we may also reason from it in reference to temperament, since, in point of fact, temperament is nothing but susceptibility to action.901 And when sympathy is in action, we may, by analyzing our idea of it, reduce it to five different heads, and may classify it as continued, or contiguous, or remote, or similar, or dissimilar.902 All these supplied Hunter with principles from which, by reasoning deductively, he attempted to explain the facts of disease; for, according to him, disease merely consists in a want of combination of actions.903 By this process of thought, he was induced to neglect those predisposing causes, to which inductive pathologists pay great attention, and with which the works of his English contemporaries were much occupied. Such causes could only be generalized from observation, and Hunter made no account of them. Indeed, he even denies their real existence, and asserts that a predisposing cause is simply an increased susceptibility to form disposition to action.904

By reasoning from the twofold ideas of action and of sympathy, Hunter constructed the deductive or synthetic part of his pathology. This he did as a Scotchman, and to this, had he always lived in Scotland, he would probably have confined himself. But being for forty years surrounded by Englishmen, and having his mind impregnated by English habits, he contracted something of their mode of thought. We, accordingly, find that a considerable portion of his pathology is as inductive as the most eager disciple of Bacon could desire; forming, in this respect, a striking contrast to the purely synthetic method of Cullen, the other great pathologist of Scotland. In the attempt, however, which Hunter made to mix these two methods, he perplexed both himself and his readers. Hence that obscurity, which even his warmest admirers have noticed, though they have not perceived its cause. Vast as his powers were, he was unable to effect a complete union between induction and deduction. That this should have happened, will not surprise any one, who considers how some of the greatest thinkers have failed in this, the most difficult of all enterprises. Among the ancients, Plato failed in induction, and all his followers failed with him; since none of them have placed sufficient confidence in facts, and in the process of reasoning from particulars to generals. Among the moderns, Bacon was deficient in deduction, and every Baconian has been similarly deficient; it being the essential vice of that school to despise reasoning from general propositions, and to underrate the value of the syllogism. It may, indeed, be doubted if the history of the world supplies more than two instances of physical philosophers being as great in one form of investigation as in the other. They are Aristotle and Newton, who wielded each method with equal ease, combining the skill and boldness of deduction with the caution and perseverance of induction, masters alike of synthesis and of analysis, as capable of proceeding from generals to particulars, as from particulars to generals, sometimes making ideas precede facts, and sometimes making facts precede ideas, but never faltering, never doubting which course to take, and never allowing either scheme unduly to encroach on its opposite. That Hunter should be unable to perform this, merely proves that he was inferior to these two men, whose almost incredible achievements entitle them to be termed the prodigies of the human race. But what he did was wonderful, and, in his own department, has never been rivalled. Of the character and extent of his inquiries, I have given a sketch, which, notwithstanding its imperfections, may serve to illustrate the antagonism of the Scotch and English intellects, by showing how the methods peculiar to each nation struggled for mastery in that great mind, which was exposed to the action of both. Which method predominated in Hunter, it would be hard to say. But it is certain, that his understanding was troubled by their conflict. It is also certain, that, owing to his love of deduction, or of reasoning from general ideas, he exercised much less sway over his English contemporaries, than he would have done if he had exclusively followed their favourite method of reasoning from particular facts. Hence, the disproportion between his influence and his merits. As to his merits, it is now admitted that, in addition to his physiological discoveries, and the great pathological views which he propounded, we may trace to him nearly all the surgical improvements which were introduced within about forty years after his death.905 He was the first who explained, and, indeed, the first who recognized, the disease of inflammation of the veins, which is of frequent occurrence, and, under the name of phlebitis, has latterly been much studied, but which, before his time, had been ascribed to the most erroneous causes.906 On general inflammation, he threw so much light, that the doctrines which he advocated, and which were then ridiculed as whimsical novelties, are now taught in the schools, and have become part of the common traditions of the medical profession.907 He, moreover, introduced what is probably the most capital improvement in surgery ever effected by a single man; namely, the practice in aneurism of tying the artery at a distance from the seat of disease. This one suggestion has saved thousands of lives; and both the suggestion, and the first successful execution of it, are entirely owing to John Hunter, who, if he had done nothing else, would, on this account alone, have a right to be classed among the principal benefactors of mankind.908

But, so far as his own immediate reputation was concerned, all was in vain. He was in the midst of a people who had no sympathy with that mode of thought which was most natural to him. They cared nothing for ideas, except with a few to direct and tangible results; he valued ideas for themselves, and for the sake of their truth, independently of all other considerations. His English contemporaries, prudent, sagacious, but short-sighted, seeing few things at a time, but seeing those things with admirable clearness, were unable to appreciate his comprehensive speculations. Hence, in their opinion, he was little else than an innovator and an enthusiast.909 Hence, too, even the practical improvements which he introduced were coldly received, because they proceeded from so suspicious a source. The great Scotchman, thrown among a nation whose habits of mind were uncongenial to his own, stood, says one of the most celebrated of his disciples, in a position of solitary and comfortless superiority.910 Indeed, so little was he regarded by that very profession of which he was the chiefest ornament, that, during the many years in which he delivered lectures in London on anatomy and on surgery, his audience never amounted to twenty persons.911

I have now completed my examination of the Scotch intellect as it unfolded itself in the seventeenth and eighteenth centuries. The difference between those two periods must strike every reader. In the seventeenth century, the ablest Scotchmen wasted their energies on theological subjects, respecting which we have no trustworthy information, and no means of obtaining any. On these topics, different persons and different nations, equally honest, equally enlightened, and equally competent, have entertained, and still entertain, the most different opinions, which they advocate with the greatest confidence, and support by arguments, perfectly satisfactory to themselves, but contemptuously rejected by their opponents. Each side deeming itself in possession of the truth, the impartial inquirer, that is, he who really loves truth, and knows how difficult it is to obtain it, seeks for some means by which he may fairly adjudicate between these conflicting pretensions, and determine which is right and which is wrong. The further he searches, the more he becomes convinced that no such means are to be found, and that these questions, if they do not transcend the limits of the human understanding, do, certainly, transcend its present resources, and have no chance of being answered, while other and much simpler problems are still unsolved. It would be strange, indeed, if we, ignorant of so many lower and subordinate matters, should be able to reach and penetrate these remote and complicated mysteries. It would be strange if we, who, notwithstanding the advances we have made, are still in the infancy of our career, and who, like infants, can only walk with unsteady gait, and are scarce able to move without stumbling, even on plain and level ground, should, nathless, succeed in scaling those dizzy heights, which, overhanging our path, lure us on where we are sure to fall. Unfortunately, however, men are, in every age, so little conscious of their deficiencies, that they not only attempt this impossible task, but believe they have achieved it. Of those who are a prey to this delusion, there are always a certain number, who, seated on their imaginary eminence, are so inflated by the fancied superiority, as to undertake to instruct, to warn, and to rebuke the rest of mankind. Giving themselves out as spiritual advisers, and professing to teach what they have not yet learned, they exhibit in their own persons that most consistent of all combinations, a combination of great ignorance with great arrogance. From this, other evils inevitably follow. The ignorance produces superstition; the arrogance produces tyranny. Hence it is, that, in a country like Scotland, where the pressure of long-continued and adverse circumstances has consolidated the power of these pretenders to wisdom, such sad results become conspicuous in every direction. Not only the national character, but also the national literature, feel their influence, and are coloured by them. It was, therefore, natural that, in Scotland, in the seventeenth century, when the authority of the clergy was most uncontrolled, the consequences of that authority should be most apparent. It was natural that a literature should be created such as that of which I have given some account; a literature which encouraged superstition, intolerance, and bigotry; a literature full of dark misgivings, and of still darker threats; a literature which taught men that it was wrong to enjoy the present, and that it was right to tremble at the future; a literature, in a word, which, spreading gloom on every side, soured the temper, corrupted the affections, numbed the intellect, and brought into complete discredit those bold and original inquiries, without which there can be no advance in human knowledge, and consequently no increase of human happiness.

To this, the literature of the eighteenth century offered a striking and most exhilarating contrast. It seemed as if, in a moment, all was changed. The Baillies, the Binnings, the Dicksons, the Durhams, the Flemings, the Frasers, the Gillespies, the Guthries, the Halyburtons, the Hendersons, the Rutherfords, and the rest of that monkish rabble, were succeeded by eminent and enterprising thinkers, whose genius lighted up every department of knowledge, and whose minds, fresh and vigorous as the morning, opened for themselves a new career, and secured for their country a high place in the annals of European intellect. Something of what they effected, I have endeavoured to narrate; much, however, has been left untold. But I have brought forward sufficient evidence to convince even the most sceptical reader of the splendour of their achievements, and of the difference between the noble literature which they produced, and those wretched compositions which disfigured the preceding century.

Still, great as the difference was, the two literatures had, as I have shown, one important point in common. Both were essentially deductive; and the proof of this I have given at considerable length, because, though it has, so far as I am aware, escaped the attention of all previous inquirers, its consequences were of the utmost moment to the fortunes of Scotland, and are, moreover, full of interest to those who, in their investigations of human affairs, desire to penetrate below the mere surface and symptoms of things.

If we take a general view of those countries where science has been cultivated, we shall find that, wherever the deductive method of inquiry has predominated, knowledge, though often increased and accumulated, has never been widely diffused. On the other hand, we shall find that, when the inductive method has predominated, the diffusion of knowledge has always been considerable, or, at all events, has been beyond comparison greater than when deduction was prevalent. This holds good, not only of different countries, but also of different periods in the same country. It even holds good of different individuals in the same period, and in the same country. If, in any civilized nation, two men, equally gifted, were to propound some new and startling conclusion, and one of these men were to defend his conclusion by reasoning from ideas or general principles, while the other man were to defend his by reasoning from particular and visible facts, there can be no doubt that, supposing all other things the same, the latter man would gain most adherents. His conclusion would be more easily diffused, simply because a direct appeal, in the first instance, to palpable facts, strikes the vulgar with immediate effect; while an appeal to principles is beyond their ken, and as they do not sympathize with it, they are apt to ridicule it. Facts seem to come home to every one, and are undeniable. Principles are not so obvious, and, being often disputed, they have, to those who do not grasp them, an unreal and illusory appearance, which weakens their influence. Hence it is that inductive science, which always gives the first place to facts, is essentially popular, and has on its side those innumerable persons, who will not listen to the more refined and subtle teachings of deductive science. Hence, too, we find historically that the establishment of the modern inductive philosophy, with its varied and attractive experiments, its material appliances, and its constant appeal to the senses, has been intimately connected with the awakening of the public mind, and coincides with that spirit of inquiry, and with that love of liberty, which have been constantly advancing since the sixteenth century. We may assuredly say, that scepticism and democracy are the two leading features of this great scientific movement. The seventeenth century, which ushered in the Baconian philosophy, was remarkable for its insubordinate spirit, especially in the country where that philosophy originated, and where it most flourished. In the next age, it was transplanted into France, and there, too, it worked upon the popular mind, and, was, as I have already pointed out, one of the principal causes of the French Revolution.

If we look still closer into this interesting question, we shall find further corroboration of the view, that the inferences of an inductive philosophy are more likely to be diffused than those of a deductive one. Inductive science rests immediately upon experience, or, at all events, upon experiment, which is merely experience artificially modified. Now, an immense majority of mankind, even in the most advanced countries, are, by the constitution of their minds, incapable of seizing general principles and applying them to daily affairs, without doing serious mischief, either to themselves, or to others. Such an application requires not only great dexterity, but also a knowledge of those disturbing causes which affect the operation of all general theorems. The task, being so difficult to perform, is rarely attempted; and average men, possessed of a tolerably sound judgment, do, with good reason, rely mainly on experience, which is to them a safer and more useful guide than any principle, however accurate and scientific it might be. This begets in their minds a prejudice on behalf of experimental inquiries, and a corresponding dislike of the opposite and more speculative method. And it can, I think, hardly be doubted, that one of the causes of the triumph of the Baconian philosophy, is the growth of the industrious classes, whose business-like and methodical habits are eminently favourable to empirical observations of the uniformities of sequence, since, indeed, on the accuracy of such observations the success of all practical affairs depends. Certainly, we find that the overthrow of the purely deductive scholasticism of the Middle Ages has been everywhere accompanied by the spread of trade; and whoever will carefully study the history of Europe, will discern many traces of a connexion between the two movements, both of which are marked by an increasing respect for material and empirical interests, and a disregard of ideal and speculative pursuits.