Hume / (English Men of Letters Series)

by Thomas Henry Huxley

"'Tis evident that all the sciences have a relation, greater or less, to human nature; and that, however wide any of them may seem to run from it, they still return back by one passage or another. Even Mathematics, Natural Philosophy, and Natural Religion are in some measure dependent on the science of Man; since they lie under the cognizance of men, and are judged of by their powers and qualities. 'Tis impossible to tell what changes and improvements we might make in these sciences were we thoroughly acquainted with the extent and force of human understanding, and could explain the nature of the ideas we employ and of the operations we perform in our reasonings.... To me it seems evident that the essence of mind being equally unknown to us with that of external bodies, it must be equally impossible to form any notion of its powers and qualities otherwise than from careful and exact experiments, and the observation of those particular effects which result from its different circumstances and situations. And though we must endeavour to render all our principles as universal as possible, by tracing up our experiments to the utmost, and explaining all effects from the simplest and fewest causes, 'tis still certain we cannot go beyond experience; and any hypothesis that pretends to discover the ultimate original qualities of human nature, ought at first to be rejected as presumptuous and chimerical....

"But if this impossibility of explaining ultimate principles should be esteemed a defect in the science of man, I will venture to affirm, that it is a defect common to it with all the sciences, and all the arts, in which we can employ ourselves, whether they be such as are cultivated in the schools of the philosophers, or practised in the shops of the meanest artisans. None of them can go beyond experience, or establish any principles which are not founded on that authority. Moral philosophy has, indeed, this peculiar disadvantage, which is not found in natural, that in collecting its experiments, it cannot make them purposely, with premeditation, and after such a manner as to satisfy itself concerning every particular difficulty which may arise. When I am at a loss to know the effects of one body upon another in any situation, I need only put them in that situation, and observe what results from it. But should I endeavour to clear up in the same manner any[15] doubt in moral philosophy, by placing myself in the same case with that which I consider, 'tis evident this reflection and premeditation would so disturb the operation of my natural principles, as must render it impossible to form any just conclusion from the phenomenon. We must, therefore, glean up our experiments in this science from a cautious observation of human life, and take them as they appear in the common course of the world, by men's behaviour in company, in affairs, and in their pleasures. Where experiments of this kind are judiciously collected and compared, we may hope to establish on them a science which will not be inferior in certainty, and will be much superior in utility, to any other of human comprehension."—(I. pp. 7-11.)

All science starts with hypotheses—in other words, with assumptions that are unproved, while they may be, and often are, erroneous; but which are better than nothing to the seeker after order in the maze of phenomena. And the historical progress of every science depends on the criticism of hypotheses—on the gradual stripping off, that is, of their untrue or superfluous parts—until there remains only that exact verbal expression of as much as we know of the fact, and no more, which constitutes a perfect scientific theory.

Philosophy has followed the same course as other branches of scientific investigation. The memorable service rendered to the cause of sound thinking by Descartes consisted in this: that he laid the foundation of modern philosophical criticism by his inquiry into the nature of certainty. It is a clear result of the investigation started by Descartes, that there is one thing of which no doubt can be entertained, for he who should pretend to doubt it would thereby prove its existence; and that is the momentary consciousness we call a present thought or feeling; that is safe, even if all other kinds of certainty are merely more or less probable inferences. Berkeley and Locke, each in his way, applied philosophical criticism in other directions; but they always, at any rate professedly, followed the Cartesian maxim of admitting no propositions to be true but such as are clear, distinct, and evident, even while their arguments stripped off many a layer of hypothetical assumption which their great predecessor had left untouched. No one has more clearly stated the aims of the critical philosopher than Locke, in a passage of the famous Essay concerning Human Understanding, which, perhaps, I ought to assume to be well known to all English readers, but which so probably is unknown to this full-crammed and much examined generation that I venture to cite it:

"If by this inquiry into the nature of the understanding I can discover the powers thereof, how far they reach, to what things they are in any degree proportionate, and where they fail us, I suppose it may be of use to prevail with the busy mind of man to be more cautious in meddling with things exceeding its comprehension: to stop when it is at the utmost extent of its tether; and to sit down in quiet ignorance of those things which, upon examination, are proved to be beyond the reach of our capacities. We should not then, perhaps, be so forward, out of an affectation of universal knowledge, to raise questions and perplex ourselves and others with disputes about things to which our understandings are not suited, and of which we cannot frame in our minds any clear and distinct perception, or whereof (as it has, perhaps, too often happened) we have not any notion at all.... Men may find matter sufficient to busy their heads and employ their hands with variety, delight, and satisfaction, if they will not boldly quarrel with their own constitution and throw away the blessings their hands are filled with because they are not big enough to grasp everything. We shall not have much reason to complain of the narrowness of our minds, if we will but employ them about what may be of use to us: for of that they are very capable: and it will be an unpardonable, as well as a childish peevishness, if we under-value the advantages of our knowledge, and neglect to improve it to the ends for which it was given us, because there are some things that are set out of the reach of it. It will be no excuse to an idle and untoward servant who would not attend to his business by candlelight, to plead that he had not broad sunshine. The candle that is set up in us shines bright enough for all our purposes.... Our business here is not to know all things, but those which concern our conduct."[16]

Hume develops the same fundamental conception in a somewhat different way, and with a more definite indication of the practical benefits which may be expected from a critical philosophy. The first and second parts of the twelfth section of the Inquiry are devoted to a condemnation of excessive scepticism, or Pyrrhonism, with which Hume couples a caricature of the Cartesian doubt; but, in the third part, a certain "mitigated scepticism" is recommended and adopted, under the title of "academical philosophy." After pointing out that a knowledge of the infirmities of the human understanding, even in its most perfect state, and when most accurate and cautious in its determinations, is the best check upon the tendency to dogmatism, Hume continues:—

"Another species of mitigated scepticism, which may be of advantage to mankind, and which maybe the natural result of the Pyrrhonian doubts and scruples, is the limitation of our inquiries to such subjects as are best adapted to the narrow capacity of human understanding. The imagination of man is naturally sublime, delighted with whatever is remote and extraordinary, and running, without control, into the most distant parts of space and time in order to avoid the objects which custom has rendered too familiar to it. A correct judgment observes a contrary method, and, avoiding all distant and high inquiries, confines itself to common life, and to such subjects as fall under daily practice and experience; leaving the more sublime topics to the embellishment of poets and orators, or to the arts of priests and politicians. To bring us to so salutary a determination, nothing can be more serviceable than to be once thoroughly convinced of the force of the Pyrrhonian doubt, and of the impossibility that anything but the strong power of natural instinct could free us from it. Those who have a propensity to philosophy will still continue their researches; because they reflect, that, besides the immediate pleasure attending such an occupation, philosophical decisions are nothing but the reflections of common life, methodised and corrected. But they will never be tempted to go beyond common life, so long as they consider the imperfection of those faculties which they employ, their narrow reach, and their inaccurate operations. While we cannot give a satisfactory reason why we believe, after a thousand experiments, that a stone will fall or fire burn; can we ever satisfy ourselves concerning any determination which we may form with regard to the origin of worlds and the situation of nature from and to eternity?"—(IV. pp. 189—90.)

But further, it is the business of criticism not only to keep watch over the vagaries of philosophy, but to do the duty of police in the whole world of thought. Wherever it espies sophistry or superstition they are to be bidden to stand; nay, they are to be followed to their very dens and there apprehended and exterminated, as Othello smothered Desdemona, "else she'll betray more men."

Hume warms into eloquence as he sets forth the labours meet for the strength and the courage of the Hercules of "mitigated scepticism."

"Here, indeed, lies the justest and most plausible objection against a considerable part of metaphysics, that they are not properly a science, but arise either from the fruitless efforts of human vanity, which would penetrate into subjects utterly inaccessible to the understanding, or from the craft of popular superstitions, which, being unable to defend themselves on fair ground, raise these entangling brambles to cover and protect their weakness. Chased from the open country, these robbers fly into the forest, and lie in wait to break in upon every unguarded avenue of the mind and overwhelm it with religious fears and prejudices. The stoutest antagonist, if he remits his watch a moment, is oppressed; and many, through cowardice and folly, open the gates to the enemies, and willingly receive them with reverence and submission as their legal sovereigns.

"But is this a sufficient reason why philosophers should desist from such researches and leave superstition still in possession of her retreat? Is it not proper to draw an opposite conclusion, and perceive the necessity of carrying the war into the most secret recesses of the enemy?... The only method of freeing learning at once from these abstruse questions, is to inquire seriously into the nature of human understanding, and show, from an exact analysis of its powers and capacity, that it is by no means fitted for such remote and abstruse subjects. We must submit to this fatigue, in order to live at ease ever after; and must cultivate true metaphysics with some care, in order to destroy the false and adulterated."—(IV. pp. 10, 11.)

Near a century and a half has elapsed since these brave words were shaped by David Hume's pen; and the business of carrying the war into the enemy's camp has gone on but slowly. Like other campaigns, it long languished for want of a good base of operations. But since physical science, in the course of the last fifty years, has brought to the front an inexhaustible supply of heavy artillery of a new pattern, warranted to drive solid bolts of fact through the thickest skulls, things are looking better; though hardly more than the first faint flutterings of the dawn of the happy day, when superstition and false metaphysics shall be no more and reasonable folks may "live at ease," are as yet discernible by the enfants perdus of the outposts.