Henry Sidgwick, "The Philosophy of Common Sense," Mind, N.S., Vol. 4, No. 14 (Apr., 1895): 145-158.

The Philosophy of Common Sense

Henry Sidgwick

An address delivered to the Glasgow Philosophical Society on Jan. 10, 1895.

When I received, some months ago, the invitation to address your society, my mind was carried irresistibly back to a period in the last century, in which, through my study of three eminent teachers whose works have had a permanent influence on my thought, I seem to feel more at home in the intellectual life of your famous University than in that even of my own. It is a period of about fifty years; beginning in 1730, when Francis Hutcheson was summoned from Dublin to fill in Glasgow the chair now worthily occupied by my friend Professor Jones; and ending in 1781, when Thomas Reid retired from the same chair to put into final literary form the teaching that he had given here for seventeen years. Between the two, as the immediate predecessor of Reid, though not the immediate successor of Hutcheson, stands the greater name of Adam Smith. I felt "in private duty bound" to select the work of one of the three as the theme of my address: the difficulty was to choose. I should have much liked to try to explain the attraction which the refinement, balance and comprehensiveness of Hutcheson's ethical views have always had for me; but on such an occasion it seemed prudent to defer to the sometimes capricious judgment of history: and in the face of that judgment, I felt diffident of my power of persuading you to regard Hutcheson's system with more than antiquarian interest. With Adam Smith, as I need hardly say, the case was altogether different. His doctrine has gone out into all lands, and his words unto the ends of the world: and hardly a year passes without some attempt being made somewhere to extract fresh instruction from his epoch-making work, or to throw fresh light on its method or its relations. But for this very reason I doubted whether I should not seem superfluous in adding my pebble to the imposing cairn of literary products that has thus been raised to his memory. The intermediate position of Reid, unquestionably a more important leader of thought than Hutcheson, unquestionably less familiar to current thought than Adam Smith, seemed on the whole to fit the opportunity best: I propose therefore this evening to present to you -- not with the fulness and exactness of a critical historian but in the lighter and more selective style allowed to an occasional utterance -- such features of Reid's philosophical work as appear to me of most enduring interest.

I will begin by endeavouring to remove a prejudice, which perhaps my very title may have produced.

"The Philosophy of Common Sense," you may say, "is not this after all an intellectual monstrosity? Philosophy is a good thing and Common Sense in its place is a good thing too: but they are both better kept apart. If we mix them, shall we not find ourselves cutting blocks with a scalpel, and using a garden-knife for the finer processes of scientific dissection?"

And I am the more afraid of this prejudgment, because in the only passage of Kant's works in which he speaks of Reid's philosophical labours, it is this antithesis that he applies in condemnation of them: and, speaking as I do in a University where the leading expositor of Kant, to Englishmen as well as Scotsmen of our age, has taught for so many years, I cannot but feel this condemnation a formidable obstacle to my efforts to claim your sympathy for Reid.

The passage I refer to is that in Kant's Prolegomena to any future Metaphysic (1783) in which he "considers with a sense of pain" how completely Hume's opponents "Reid, Oswald, Beattie, and even Priestley" missed the point of Hume's problem. Instead of answering Hume's sceptical reasoning by "probing more deeply into the nature of reason," as Kant believed himself to have done, "they discovered a more convenient means of putting on a bold face without any proper insight into the question, by appealing to the common sense of mankind . . . a subtle discovery for enabling the most vapid babbler" without a "particle of insight" to hold his own against the most penetrating thinker.

The censure you see is strong: but is it thoroughly intelligent? Reid, says the critic, has not caught Hume's point. Has Kant caught Reid's? I venture to doubt whether he ever gave himself a chance of catching it.

This for two reasons. First, look at the names he puts together, "Reid, Oswald, Beattie;" -- the first a thinker of indubitable originality; the third a man of real, but chiefly literary, ability, a poet by choice and a philosopher from a sense of duty; the second a theological pamphleteer. Is it likely that Kant would have thus bracketed the three, if he had really read them? How came he to put them on a par? That is easily explained. He had doubtless read Priestley's examination which treats the three together, and which, written as it was primarily from a theological point of view, gives even a larger space to Oswald. This explains Kant's odd conjunction of names, "Reid, Oswald, Beattie, and even Priestley," -- even, that is, their critic Priestley. I imagine Kant was on general grounds more likely to be attracted by Priestley's book than by Reid's, since he had a keen interest in the progress of contemporary physical science, and Priestley had here a well-deserved reputation: and certainly the Reid who appears in Priestley's pages, misquoted, misrepresented and misunderstood, was likely enough to be regarded as another Oswald.

My second reason is that if Kant had ever studied Reid's Inquiry into the Human Mind he could hardly have failed to extend his studies to the Hume to whom Reid was replying. This may startle you. "What," you may say, "Kant not read Hume: why any shilling handbook of the history of philosophy will tell you that Hume's scepticism woke up Kant from his dogmatic slumbers." Certainly, but it was not the same scepticism as that which woke up Reid to construct the Philosophy of Common Sense: it was the veiled, limited and guarded scepticism of the Inquiry into the Human Understanding, not the frank, comprehensive and uncompromising scepticism of the Treatise on Human Nature. Kant's Hume is a sceptic who ventures modestly to point out the absence of a rational ground for his expectation that the future will resemble the past, while in the same breath hastening to assure the reader that his expectation remains unshaken by his arguments. Reid's Hume is a sceptic who boldly denies the infinite divisibility of space, who professes to have in his intellectual laboratory a solvent powerful enough to destroy the force of the most cogent demonstration, and who ventures to tell his fellow-men plainly that they are each and all "nothing but bundles of different perceptions, succeeding each other with inconceivable rapidity." I think that if Kant had even looked into Reid's Inquiry, the difference between the earlier and the later Hume must have struck him, and he must have been led on to read the Treatise on Human Nature; whereas it is evident and admitted that he never did read it.

Do you still want proof that Kant did not catch Reid's point? I have a witness to bring forward whom Kant himself would have allowed to be a good witness, -- Mr David Hume: who was persuaded by a common friend to peruse parts of Reid's work before it appeared, and to write his view of them to the author. Hume did not much like the task in prospect: "I wish," he grumbles to the common friend, "that the parsons would confine themselves to their old occupation of worrying one another, and leave philosophers to argue with moderation, temper, and good manners." In fact, he expects another Warburton: but when he has read the MS. his tone changes. "It is certainly very rare," he writes to Reid, "that a piece so deeply philosophical is wrote with so much spirit, and affords so much entertainment to the reader. & . . . There are some objections," he goes on, "that I would propose, but I will forbear till the whole can be before me. I will only say that if you have been able to clear up these abstruse and important topics, instead of being mortified, I shall be so vain as to pretend to a share of the praise: and shall think that my errors, by having at least some coherence, had led you to make a strict review of my principles, which were the common ones, and to perceive their futility."

Well, I think you will agree with me that this is a charmingly urbane letter, from a free-thinker of established literary reputation to a parson turned professor, as yet hardly known in the world of letters, who had hit him some smart blows and ventured to laugh at him a little as well as argue with him. But Hume recognises that the parson unexpectedly writes like a philosopher: and Hume, as we saw, has a high ideal of the manner in which philosophers should conduct their debates; and it is a pleasure to find him acting up to his ideal, a pleasure all the greater from the rarity with which it is afforded to the student of philosophical controversy.

But it was not Hume's urbanity that I wished now to dwell: I wished to point out that it never occurs to Hume that Reid has appealed from the expert to the vulgar, and endeavoured to avoid his conclusions without answering his arguments. What rather strikes Hume is the philosophic depth that his antagonist has shown in attacking his fundamental assumptions; -- which were, as he says, the common ones, and which Reid, accordingly had traced back through Berkeley and Locke to the start of modern philosophy in Descartes. It is difficult, I think, for us to appreciate equally the penetration shown in this historical apercu, because the connexion of ideas that Reid makes apparent now seems to us so obvious and patent. But this is the case with many important steps in the development of philosophical thought: when once the step has been taken, it appears so simple and inevitable that we can hardly feel that it required intellectual force and originality to take it. You remember, perhaps, the depreciatory remark made on Christopher Columbus by a schoolboy who "didn't see why so much fuss should be made about his discovery of America, since, if he went that way at all, he could not well miss it." Similarly it now seems to us that if Reid "went that way at all" he could not fail to find the source of the Idealism of Berkeley and the pulverizing scepticism of Hume in Locke's assumption that the immediate object of the mind in external perception is its own ideas: and that finding this view equally in Malebranche, he could not fail to trace it to Descartes. His merit lay in the independence of thought required to free himself from this assumption, question it and hunt it home: and this merit Hume evidently recognised.

And now, perhaps, I may have persuaded some of my hearers that Kant entirely failed to see what Reid and his followers were driving at. But if so, I have gone to far, and persuaded them of more than I intended. The appeal to vulgar common sense has an important place in Reid's doctrine: he does rely on it: nor can I defend him from the charge that he relies on it too much. He does hold that the mere ridiculousness of Hume's conclusions is a good reason for disbelieving them: and even in his later and maturer treatise he speaks of the sense of the ridiculous as a guide to philosophic truth, in language that lacks his usual circumspection. For our sense of the ridiculous is manifestly stirred by the mere incongruity of an opinion with our intellectual habits: a strange truth is no less apt to excite it than a strange error. When the Copernican theory was slowly winning its way to acceptance, even the grave Milton allowed himself a jest on "the new carmen who drive the earth about": and I can remember how, when the Darwinian theory was new, persons of the highest culture cracked their jokes on the zoologist's supposed private reasons for the absurd conclusion that his ancestor was a monkey. And this is doubtless all for the best: laughter is a natural and valuable relief in many perplexities and disturbances of life, and I do not see why it should not relieve the disturbance caused by the collision of new opinions with old: only let us remember that it is evidence of nothing except the mere fact of collision. But, though Reid does rely more than he ought on the argumentum ad risum, he is not so stupid as to think that a volume is required to exhibit this argument. He does say to the plain man, "If philosophy befools her votaries, and leads them into these quagmires of absurdity, beware of her as an ignis fatuus": but he immediately adds, "Is it, however, certain that this fair lady is of the party? Is it not possible that she may have been misrepresented?" and that she has been misrepresented is the thesis which he aims at proving.

In the course of the proof, no doubt, he leads us again to Common Sense, as the source and warrant of certain primary data of knowledge at once unreasoned and indubitable: but the Common Sense to which we are thus led is not that of the vulgar as contrasted with the philosopher: Reid's point is that the philosopher inevitably shares it with the vulgar. Whether a philosopher has been developed out of a monkey may possibly be still an open question; but there can be no doubt that he is developed out of a man; and, if we consider his intellectual life as a whole, we may surmise that the larger part of it is occupied with the beliefs that he still shares with the unphilosophical majority of his contemporaries. It is on this fact that Reid's appeal to him is based. He refers to Hume's account of the manner in which, after solitary reflection has environed him with the clouds and darkness of doubt, the genial influence of "dinner, backgammon, and social talk" dispels these doubts and restores his belief in the world without and the self within: and Reid takes his stand with those who are "so weak as to imagine that they ought to have the same belief in solitude and in company." His essential demand, therefore, on the philosopher, is not primarily that he should make his beliefs consistent with those of the vulgar, but that he should make them consistent with his own; and the legitimacy of the demand becomes, I think, more apparent, when we regard it as made in the name of Philosophy rather than in the name of Common Sense. For when we reflect on plain Common Sense, -- on the body of unreasoned principles of judgment which we and other men are in the habit of applying in ordinary thought and discourse, -- we find it certainly to some extent confused and inconsistent: but it is not clear that it is the business of Common Sense to get rid of these confusions and inconsistencies, so long as they do not give trouble in the ordinary conduct of life: at any rate is is not its most pressing business, since system-making is not its affair. But system-making is preeminently the affair of Philosophy, and it cannot willingly tolerate inconsistencies: at least if it has to tolerate them, as I sadly fear that it has, it can only tolerate them as a physician tolerates a chronic imperfection of health, which he can only hope to mitigate and not completely to cure.

Accordingly, in Reid's view it is the duty of a philosopher -- his duty as a philosopher -- to aim steadily and persistently at bringing the common human element of his intellectual life into clear consistency with the special philosophic element. And Reid is on the whole perfectly aware, -- though his language occasionally ignores it, -- that for every part of this task the special training and intellectual habits of the philosopher are required. For the fundamental beliefs which the philosopher shared with the plain man can only be defined with clearness and precision by one who has reflected systematically, as an ordinary man does not reflect, on the operations of his own mind; even the elementary distinction between sensation and perception is, Reid admits, only apprehended by the plain man in a confused form. To bring the distinction into clear consciousness, to attend to "sensation and perception each by itself, and to attribute nothing to one which belongs to the other," requires, he tells us, "a degree of attention to what passes in our own minds, and a talent for distinguishing things that differ, which is not to be expected in the vulgar." The philosopher alone can do it: but in order to do it, he must partially divest himself of his philosophic peculiarities. That is, he must temporarily put out of his mind the conclusions of any system he may have learnt or adopted, and merely bring his trained faculty of reflective attention to the observation and analysis of the common human element of his thought.

But if it be admitted that the philosopher alone is capable of the steady and clear attention required to ascertain the fundamental beliefs of Common Sense, what valid evidence is there of the general assent to these beliefs on which Reid lays stress, and which, indeed, the term implies? He seems to be in a dilemma; either the many must be held capable of reflective analysis, or the decision on questions of fundamental belief must after all be limited to the expert few. The difficulty is partly met by pointing out that the philosophical faculty required to judge of such a statement when made; just as few of us could have found out the axioms required in the study of geometry, but we could easily see the truth of Euclid's at a very early age. Still, granting this, I think that Reid presses too far the competence of plain man even to judge of philosophical first principles. It is true, as he urges, that this judgment requires no more than a "sound mind free from prejudice and a distinct conception of the questions": but it does not follow, as Reid seems to think, that "every man is a competent judge, the learned and unlearned, the philosopher and day-labourer alike:" because a good deal of the painful process we call "learning" is normally needed to realise these apparently simple requirements, freedom from prejudice and distinctness of conception. I will not affirm that no day-labourer could attain a distinct conception of the positions that Reid is defending against Berkeley and Hume: but I venture to think that a day-labourer who could convince us that he had attained it would be at once recognised as a born philosophy, incontrovertibly qualified by native genius for membership of the society that I have the honour to address.

At the same time I cannot think Reid wrong in holding that the propositions he is most concerned to maintain as first principles are implicitly assented to by men in general. That for ordinary men sense-perception involves a belief in the existence of a thing perceived, independent of the perception: that similarly consciousness involves a belief in the existence of a permanent identical subject of changing conscious states: that ordinary moral judgment involves the belief in a real right and wrong in human action, capable of being known by a moral agent and distinct in idea from what conduces to his interest: that in ordinary thought about experience we find implicit the unreasoned assumption that every change must have a cause, and a cause adequate to the effect, all this I think will hardly be denied by any one who approaches the question with a fair mind. He may of course still regard it as unphilosophical to rest the validity of these beliefs on the fact of their general acceptance. But here again it must be said that Reid's own deference to general assent is of a strictly limited and subordinate kind. He is far from wishing truth to be determined by votes: he only urges that "authority, though tyrannical as a mistress, is useful as a handmaid to private judgment." He points out that even in the exactest science authority actually has this place: even a mathematician who has demonstrated a novel conclusion is strengthened in his belief in it by the assent of other mathematical experts who have examined his demonstration, and is "reduced to a kind of suspense" by their dissent.

That is, I think, undeniable: and perhaps we may separate Reid's just and moderate statement of the claims of Authority from his exaggerated view of the competence of untrained intellects to deal with philosophical first principles; and simply take it as a cardinal point in the philosophy of Common Sense that a difference in judgment from another whom he has no reason to regard as less competent to judge them himself naturally and properly reduces a thinker to a "kind of suspense." When the conflict relates to a demonstrated conclusion, it leads him to search for a flaw in the opponent's demonstration; but when it relates to a first principle, primary datum, or fundamental assumption, this resource appears to be excluded: and then, perhaps, when he has done all that he can to remove any misunderstanding of the question at issue, the Common Sense philosopher may be allowed to derive some support from the thought that his own conviction is shared by the great majority of those whose judgments have built up and continually sustain the living fabric of our common thought and knowledge. And this, I think, is all that Reid really means to claim.

I have now, I hope, succeeded in making clear the general relation which Reid's epistemology bears to his psychology. I have not used these modern terms, because Reid himself blends the two subjects under the single notion of "Philosophy of the Human Mind": but it is necessary, in any careful estimate of his work, to distinguish the process of psychological distinction and analysis through which the fundamental beliefs of Common Sense are ascertained, from the arguments by which their validity is justified. I do not propose to enter into the details of Reid's psychological view, which has largely become antiquated through the progress of mental science. But if Locke is the first founder of the distinctively British study, Empirical Psychology, of which the primary method is introspective observation and analysis, I think Reid has a fair claim to be regarded as a second founder: and even now his psychological work may be studied with interest from the patient fidelity of his self-observation, the acumen of his reflective analysis, and, especially, his entire freedom from the vague materialism that, in spite of Descartes, still hung about the current philosophical conception of Mind and its operations. It is, indeed, in the task of exposing the unwarrantable assumptions generated by this vague materialism that the force and penetration of Reid's intellect is most conspicuously shown.

Let me briefly note this in the case of the beliefs involved in ordinary sense-perception, since this problem occupies a leading place in his discussion. Not, I ought to say, that he is specially interested in this problem on its own account: he makes it quite clear that it is on far greater issues that his thought is really set. God, Freedom, Duty, the spirituality of human nature, -- these are, for Reid as for Kant, the grave matters really at stake in the epistemological controversy. But these greater matters, for the very reason of their supreme importance, are apt to stir our deepest emotions so strongly as to render difficult the passionless precision of analysis and reasoning which Reid rightly held to be needful for the attainment of philosophical truth: while at the same time it is clear to him that all the questions hang together, and that the decision of one in the sense that he claims will carry with it the similar determination of the rest.

Accepting this view then, and remembering that in a trivial case we are trying no trivial issue, let us examine his treatment of the cognition by Mind of particular material things. Here Reid's task, as he ultimately saw, was merely carrying further the work of Descartes. By clearly distinguishing the motions of material particles antecedent to perception from perception itself as a psychical fact, Descartes had got rid of the old psychophysical muddle, by which forms or semblances of things perceived by the senses were supposed somehow to get into the brain through the "animal spirits" and so into the mind. But he had not equally got rid of the view that perception was the getting of an idea in the mind, from which the existence of a thing outside the mind like the idea had to be somehow inferred. This view is definitely held, not only by his disciple Malebranche but by his independent successor Locke. They do not see what Reid came to see, that the normal perception of an external object presents itself to introspection as an immediate cognition: that is, as a cognition which has no psychical mediation, no inference in it. What prevented them and others from seeing this was, mainly, a naive assumption that the mind can only know immediately what is "present" to it, and that things outside the body cannot be thus present; as the mind cannot go out to them and they cannot get into the mind, only the ideas of them can get in. It was reserved to Reid to point out the illegitimacy of this assumption, and to derive it from a confused half unconscious transfer to Mind and its functions of cognition, of the conditions under which body acts on body in ordinary physical experience. When the assumption is made explicit and traced to its source, it loses, I think, all appearance of validity.

It is to be observed, that in affirming external perception to be an immediate cognition, Reid does not of course mean that it is physically uncaused. He only means that the perceiving mind has not a double object, its own percept and a non-mental thing like its percept: and accordingly that our normal conviction of the present existence of the non-mental thing perceived is not a judgment attained by reasoning, but a primary datum of knowledge. He recognizes like his predecessors that it has physical antecedents, movements of material particles both without and within the organism. And he recognizes, more distinctly than his predecessors, that it has psychical antecedents and concomitants, i.e. sensations which he carefully distinguishes from the perception that they suggest and accompany. A consideration of these antecedents may possibly affect our reflective confidence in the cognition that follows them, -- that question I will deal with presently, -- but at any rate it cannot properly modify our view of the content of this cognition as ascertained by introspective observation. This, I think, remains true after duly taking account of the valuable work that has been done since Reid's time, in ascertaining more accurately the antecedents and concomitants of our common perceptions of extended matter. Whatever view we may take on the interesting but still disputed questions as to the precise manner in which visual, tactual, and muscular feelings have historically been combined in the genesis of our particular perceptions and general notions of matter and space, -- there can still be no doubt of the fundamental difference in our present consciousness between these perceptions or notions and any combinations of muscular, tactual, and visual feelings.

It has indeed been held, by an influential school of British psychologists, that this manifest difference is merely apparent and illusory: it has been held that by a process of "mental chemistry" sensations and images of sensation have been "compounded" into what we now distinguish as perceptions and conceptions of matter in space, and that the latter really consist of sensations and images of sensation, just as water really consists of oxygen and hydrogen. But this view involves a second illegitimate transfer of physical conditions to psychical facts; and Reid would certainly have rejected "mental chemistry" in this application as unhesitatingly as he does reject it when applied to support the conclusion that a "cluster of the ideas of sense, properly combined may make up the idea of a mind." He would have rejected it for the simple reason that we have no ground for holding any fact of consciousness to be other than careful introspection declares it to be. In the case of material chemistry, the inference that a compound consists of certain elements depends on experimental proof that we can not only make the compound out of the elements, but can also make the elements again out of the combined. But even if we grant that our cognitions of Matter and Space, of Self and Duty, are derived from more elementary feelings, it is certain that no psychical experiment will enable us to turn them into such feelings again: the later phenomena, if products, are biological not chemical products, resulting from evolution, not mere composition.

Still it may be said, granting the existence of cognitions and beliefs that cannot now be resolved into more elementary feelings, and that present themselves in ordinary thought with the character of unreasoned certitude, systematic reflection on these beliefs and their antecedents must render it impossible to accept them as trustworthy premises for philosophical reasoning. It is a commonplace that the senses deceive, and the more we learn of the psychophysical process of sense-perception, the more clear it becomes why and how they must deceive. Even apart from cases of admitted illusion, philosophical reflection on normal perception continually shows us, as Hume urges, a manifest difference between the actual percept and what we commonly regard as the real thing perceived. Thus, Hume says, "the table which we see seems to diminish as we remove farther from it: but the real table which exists independent of us suffers no alteration. It was, therefore, nothing but its image which was present to the mind. These are the obvious dictates of reason." In answering this line of objection Reid partly relies on a weak distinction between original and acquired perception, which the progress of science has rendered clearly untenable and irrelevant. Apart from this his really effective reply is twofold. First he points out that the very evidence relied upon to show the unreality of sense-percepts really affords striking testimony to the general validity of the belief in an independent reality known through sense-perception. It is by trusting, not by distrusting, this fundamental belief that Common Sense organised into Science continually at once corrects and confirms crude Common Sense. Take Hume's case of the table. If nothing but images were present to the mind, how could we ever know that there exists a real table which does not alter while the visible magnitude changes its distance from us? The plain man knows this through an acquired perception, by which he habitually judges of real magnitude from visible appearances: but science carries the knowledge further, enabling us to predict exactly what appearance a given portion of extended matter will exhibit at any given distance from the spectators. Now all this coherent, precise and unerring prediction rests upon innumerable sense-perceptions; and the scientific processes which have made it possible have been carried on throughout the basis of the vulgar belief in the independent existence of the matter perceived. "Is it not absurd," Reid asks, "to suppose that a false supposition of the rude vulgar has been so lucky in solving an infinite number of phenomena of nature?"

Suppose, however, that the opponent resists this argument: suppose he maintains that, though physical science may find the independent existence of matter a convenient fiction, -- as mathematicians find it convenient to feign that they can extract the square root of negative quantities, -- still in truth Mind can know only mental facts -- feelings and thoughts. Suppose he further urges that the common belief in the independent existence of the object of perception is found on reflection to have no claim to philosophic acceptance, because while admittedly unreasoned it cannot be said to be strictly intuitive: -- granted that I may directly perceive the table before me, I cannot directly perceive that it exists independently of my perception. To this line of argument Reid has another line of reply. He points out to the Idealist that he does not escape from this kind of unreasoned belief by refusing to recognise a reality beyond consciousness. He has still to rely on data of knowledge which are open to the same objections as the belief in the independent existence of matter. For instance, he has to rely on memory. If sense-perception is fallible, memory is surely more fallible; if we do not know intuitively and cannot prove that what we perceive really exists independently of our perception, still less can we either know intuitively or prove that what we recollect really happened: if on reflection we find it difficult to conceive how the Non-ego can be known by the Ego, there is surely an equal difficulty in understanding how the Present Ego can know the Past. And yet once cease to rely on memory, and intellectual life becomes impossible: even in reasoning beyond the very simplest we have to rely on our recollection of previous steps in reasoning. A pure system of truths reasoned throughout from rational intuitions may be the philosophic ideal: but it is as true of the intellectual as of the physical life that living somehow is prior to living ideally well: and if we are to live at all, we must accept some beliefs that cannot claim Reason for their source. Is it not then, Reid urges, arbitrary and unphilosophical to acquiesce tranquilly in some of these beliefs of Common Sense, and yet obstinately to fight against others that have an equal warrant of spontaneous certitude? May we not rather say that it is the duty of a philosopher to give impartially a provisional acceptance to all such beliefs, and then set himself to clarify them by reflection, remove inadvertencies, confusions and contradictions, and as far as possible build together the purged results into an ordered and harmonious system of thought?

If, finally, the opposing philosopher answers that he cannot be satisfied by any system that is not perfectly transparent to reason, Reid does not altogether refuse him his sympathy, although he cannot encourage him to hope. "I confess," he says, "after all that the evidence of reasoning, and of necessary and self-evident truths, seems to be the least mysterious and the most perfectly comprehended & . . . the light of truth so fills my mind in these cases that I can neither conceive nor desire anything more satisfying. On the other hand, when I remember distinctly a past event, or see an object before my eyes," though "this commands my belief no less than an axiom & . . . I seem to want that evidence which I can best comprehend and which gives perfect satisfaction to an inquisitive mind." And "to a philosopher who has been accustomed to think that the treasure of his knowledge is the acquisition of his reason, it is no doubt humiliating to find" that "his knowledge of what really exists or did exist comes by another channel" and that "he is led to it" as it were "in the dark." "It is no wonder" then "that some philosophers should invent vain theories to account for this knowledge:" while others "spurn at a knowledge they cannot account for and vainly attempt to throw it off." But all such "attempts" he holds, are as impracticable as "an attempt to fly."

The passage from which I have quoted was published in 1785, when Reid was seventy-five years of age. Even before it was published, attempts at aerial navigation had suddenly come to seem less chimerical in the physical world; and, before the end of the century, in the world of thought, attempts to transcend and rationally account for the beliefs of Common Sense -- more remarkable than any dreamt of by Reid -- had begun to excite some interest even in our insular mind. The nineteenth century is now drawing to its close; and these attempts to fly are still going on, both in the physical and in the intellectual world; but in neither region, according to my information, have they yet attained a triumphant success. At the same time our age, which has seen so many things achieved that were once thought impossible, may without presumption contemplate such attempts in a somewhat more hopeful spirit than was possible to Reid: and I should be sorry to say anything here to damp the noble ardour or to depress the high aspirations that ought to animate a society like yours. But if there should be any one among you who, desirous to philosophize and yet fearing the fate of Icarus, may prefer to walk in the dimness and twilight of the lower region in which my discourse has moved, -- then I venture to think that he may even now find profit in communing with the earnest, patient, lucid and discerning intellect of the thinker, who, in the history of modern speculation, has connected the name of Scotland with the Philosophy of Common Sense.