[155] Life of Mackintosh, ii. 235-37.
[156] Begun for the Encyclopædia Metropolitana in 1818; and published in 1835-37. Dugald Stewart's chief criticism is in his Essays (Works, v. 149-188). John Fearn published his Anti-Tooke in 1820.
If English philosophy was a blank, there was still a leader of high reputation in Scotland. Dugald Stewart (1753-1828) had a considerable influence upon the Utilitarians. He represented, on the one hand, the doctrines which they thought themselves specially bound to attack, and it may perhaps be held that in some ways he betrayed to them the key of the position. Stewart[157] was son of a professor of mathematics at Edinburgh. He studied at Glasgow (1771-72) where he became Reid's favourite pupil and devoted friend. In 1772 he became the assistant, and in 1775 the colleague, of his father, and he appears to have had a considerable knowledge of mathematics. In 1785 he succeeded Adam Ferguson as professor of moral philosophy and lectured continuously until 1810. He then gave up his active duties to Thomas Brown, devoting himself to the completion and publication of the substance of his lectures. Upon Brown's death in 1820, he resigned a post to which he was no longer equal. A paralytic stroke in 1822 weakened him, though he was still able to write. He died in 1828.
If Stewart now makes no great mark in histories of philosophy, his personal influence was conspicuous. Cockburn describes him as of delicate appearance, with a massive head, bushy eyebrows, gray intelligent eyes, flexible mouth and expressive countenance. His voice was sweet and his ear exquisite. Cockburn never heard a better reader, and his manners, though rather formal, were graceful and dignified. James Mill, after hearing Pitt and Fox, declared that Stewart was their superior in eloquence. At Edinburgh, then at the height of its intellectual activity, he held his own among the ablest men and attracted the loyalty of the younger. Students came not only from Scotland but from England, the United States, France and Germany.[158] Scott won the professor's approval by an essay on the 'Customs of the Northern Nations.' Jeffrey, Horner, Cockburn and Mackintosh were among his disciples. His lectures upon Political Economy were attended by Sydney Smith, Jeffrey and Brougham, and one of his last hearers was Lord Palmerston. Parr looked up to him as a great philosopher, and contributed to his works an essay upon the etymology of the word 'sublime,' too vast to be printed whole. Stewart was an upholder of Whig principles, when the Scottish government was in the hands of the staunchest Tories. The irreverent young Edinburgh Reviewers treated him with respect, and to some extent applied his theory to politics. Stewart was the philosophical heir of Reid; and, one may say, was a Whig both in philosophy and in politics. He was a rationalist, but within the limits fixed by respectability; and he dreaded the revolution in politics, and believed in the surpassing merits of the British Constitution as interpreted by the respectable Whigs.
Stewart represents the 'common sense' doctrine. That name, as he observes, lends itself to an equivocation. Common sense is generally used as nearly synonymous with 'mother wit,' the average opinion of fairly intelligent men; and he would prefer to speak of the 'fundamental laws of belief.'[159] There can, however, be no doubt that the doctrine derived much of its strength from the apparent confirmation of the 'average opinion' by the 'fundamental laws.' On one side, said Reid, are all the vulgar; on the other all the philosophers. 'In this division, to my great humiliation, I find myself classed with the vulgar.'[160] Reid, in fact, had opposed the theories of Hume and Berkeley because they led to a paradoxical scepticism. If it be, as Reid held, a legitimate inference from Berkeley that a man may as well run his head against a post, there can be no doubt that it is shocking to common sense in every acceptation of the word. The reasons, however, which Reid and Stewart alleged for not performing that feat took a special form, which I am compelled to notice briefly because they set up the mark for the whole intellectual artillery of the Utilitarians. Reid, in fact, invented what J. S. Mill called 'intuitions.' To confute intuitionists and get rid of intuitions was one main purpose of all Mill's speculations. What, then, is an 'intuition'? To explain that fully it would be necessary to write once more that history of the philosophical movement from Descartes to Hume, which has been summarised and elucidated by so many writers that it should be as plain as the road from St. Paul's to Temple Bar. I am forced to glance at the position taken by Reid and Stewart because it has a most important bearing upon the whole Utilitarian scheme. Reid's main service to philosophy was, in his own opinion,[161] that he refuted the 'ideal system' of Descartes and his followers. That system, he says, carried in its womb the monster, scepticism, which came to the birth in 1739,[162] the date of Hume's early Treatise. To confute Hume, therefore, which was Reid's primary object, it was necessary to go back to Descartes, and to show where he deviated from the right track. In other words, we must trace the genealogy of 'ideas.' Descartes, as Reid admitted, had rendered immense services to philosophy. He had exploded the scholastic system, which had become a mere mass of logomachies and an incubus upon scientific progress. He had again been the first to 'draw a distinct line between the material and the intellectual world'[163]; and Reid apparently assumes that he had drawn it correctly. One characteristic of the Cartesian school is obvious. Descartes, a great mathematician at the period when mathematical investigations were showing their enormous power, invented a mathematical universe. Mathematics presented the true type of scientific reasoning and determined his canons of inquiry. The 'essence' of matter, he said, was space. The objective world, as we have learned to call it, is simply space solidified or incarnate geometry. Its properties therefore could be given as a system of deductions from first principles, and it forms a coherent and self-subsistent whole. Meanwhile the essence of the soul is thought. Thought and matter are absolutely opposed. They are contraries, having nothing in common. Reality, however, seems to belong to the world of space. The brain, too, belongs to that world, and motions in the brain must be determined as a part of the material mechanism. In some way or other 'ideas' correspond to these motions; though to define the way tried all the ingenuity of Descartes' successors. In any case an idea is 'subjective': it is a thought, not a thing. It is a shifting, ephemeral entity not to be fixed or grasped. Yet, somehow or other, it exists, and it 'represents' realities; though the divine power has to be called in to guarantee the accuracy of the representation. The objective world, again, does not reveal itself to us as simply made up of 'primary qualities'; we know of it only as somehow endowed with 'secondary' or sense-given qualities: as visible, tangible, audible, and so forth. These qualities are plainly 'subjective'; they vary from man to man, and from moment to moment: they cannot be measured or fixed; and must be regarded as a product in some inexplicable way of the action of matter upon mind; unreal or, at any rate, not independent entities.
In Locke's philosophy, the 'ideas,' legitimate or illegitimate descendants of the Cartesian theories, play a most prominent part. Locke's admirable common sense made him the leader who embodied a growing tendency. The empirical sciences were growing; and Locke, a student of medicine, could note the fallacies which arise from neglecting observation and experiment, and attempting to penetrate to the absolute essences and entities. Newton's great success was due to neglecting impossible problems about the nature of force in itself—'action at a distance' and so forth—and attention to the sphere of visible phenomena. The excessive pretensions of the framers of metaphysical systems had led to hopeless puzzles and merely verbal solutions. Locke, therefore, insisted upon the necessity of ascertaining the necessary limits of human knowledge. All our knowledge of material facts is obviously dependent in some way upon our sensations—however fleeting or unreal they may be. Therefore, the material sciences must depend upon sense-given data or upon observation and experiment. Hume gives the ultimate purpose, already implied in Locke's essay, when he describes his first treatise (on the title page) as an 'attempt to introduce the experimental mode of reasoning into moral subjects.' Now, as Reid thinks, the effect of this was to construct our whole knowledge out of the representative ideas. The empirical factor is so emphasised that we lose all grasp of the real world. Locke, indeed, though he insists upon the derivation of our whole knowledge from 'ideas,' leaves reality to the 'primary qualities' without clearly expounding their relation to the secondary. But Berkeley, alarmed by the tendency of the Cartesian doctrines to materialism and mechanical necessity, reduces the 'primary' to the level of the 'secondary,' and proceeds to abolish the whole world of matter. We are thus left with nothing but 'ideas,' and the ideas are naturally 'subjective' and therefore in some sense unreal. Finally Hume gets rid of the soul as well as the outside world; and then, by his theory of 'causation,' shows that the ideas themselves are independent atoms, cohering but not rationally connected, and capable of being arbitrarily joined or separated in any way whatever. Thus the ideas have ousted the facts. We cannot get beyond ideas, and yet ideas are still purely subjective. The 'real' is separated from the phenomenal, and truth divorced from fact. The sense-given world is the whole world, and yet is a world of mere accidental conjunctions and separation. That is Hume's scepticism, and yet according to Reid is the legitimate development of Descartes' 'ideal system.' Reid, I take it, was right in seeing that there was a great dilemma. What was required to escape from it? According to Kant, nothing less than a revision of Descartes' mode of demarcation between object and subject. The 'primary qualities' do not correspond in this way to an objective world radically opposed to the subjective. Space is not a form of things, but a form imposed upon the data of experience by the mind itself. This, as Kant says, supposes a revolution in philosophy comparable to the revolution made by Copernicus in astronomy. We have completely to invert our whole system of conceiving the world. Whatever the value of Kant's doctrine, of which I need here say nothing, it was undoubtedly more prolific than Reid's. Reid's was far less thoroughgoing. He does not draw a new line between object and subject, but simply endeavours to show that the dilemma was due to certain assumptions about the nature of 'ideas.'
The real had been altogether separated from the phenomenal, or truth divorced from fact. You can only have demonstrations by getting into a region beyond the sensible world; while within that world—that is, the region of ordinary knowledge and conduct—you are doomed to hopeless uncertainty. An escape, therefore, must be sought by some thorough revision of the assumed relation, but not by falling back upon the exploded philosophy of the schools. Reid and his successors were quite as much alive as Locke to the danger of falling into mere scholastic logomachy. They, too, will in some sense base all knowledge upon experience. Reid constantly appeals to the authority of Bacon, whom he regards as the true founder of inductive science. The great success of Bacon's method in the physical sciences, encouraged the hope, already expressed by Newton, that a similar result might be achieved in 'moral philosophy.'[164] Hume had done something to clear the way, but Reid was, as Stewart thinks, the first to perceive clearly and justly the 'analogy between these two different branches of human knowledge.' The mind and matter are two co-ordinate things, whose properties are to be investigated by similar methods. Philosophy thus means essentially psychology. The two inquiries are two 'branches' of inductive science, and the problem is to discover by a perfectly impartial examination what are the 'fundamental laws of mind' revealed by an accurate analysis of the various processes of thought. The main result of Reid's investigations is given most pointedly in his early Inquiry, and was fully accepted by Stewart. Briefly it comes to this. No one can doubt that we believe, as a fact, in an external world. We believe that there are sun and moon, stones, sticks, and human bodies. This belief is accepted by the sceptic as well as by the dogmatist, although the sceptic reduces it to a mere blind custom or 'association of ideas.' Now Reid argues that the belief, whatever its nature, is not and cannot be derived from the sensations. We do not construct the visible and tangible world, for example, simply out of impressions made upon the senses of sight and touch. To prove this, he examines what are the actual data provided by these senses, and shows, or tries to show, that we cannot from them alone construct the world of space and geometry. Hence, if we consider experience impartially and without preconception, we find that it tells us something which is not given by the senses. The senses are not the material of our perceptions, but simply give the occasions upon which our belief is called into activity. The sensation is no more like the reality in which we believe than the pain of a wound is like the edge of the knife. Perception tells us directly and immediately, without the intervention of ideas, that there is, as we all believe, a real external world.
Reid was a vigorous reasoner, and credit has been given to him by some disciples of Kant's doctrine of time and space. Schopenhauer[165] says that Reid's 'excellent work' gives a complete 'negative proof of the Kantian truths'; that is to say, that Reid proves satisfactorily that we cannot construct the world out of the sense-given data alone. But, whereas Kant regards the senses as supplying the materials moulded by the perceiving mind, Reid regards them as mere stimuli exciting certain inevitable beliefs. As a result of Reid's method, then, we have 'intuitions.' Reid's essential contention is that a fair examination of experience will reveal certain fundamental beliefs, which cannot be explained as mere manifestations of the sensations, and which, by the very fact that they are inexplicable, must be accepted as an 'inspiration.'[166] Reid professes to discover these beliefs by accurately describing facts. He finds them there as a chemist finds an element. The 'intuition' is made by substituting for 'ideas' a mysterious and inexplicable connection between the mind and matter.[167] The chasm exists still, but it is somehow bridged by a quasi-miracle. Admitting, therefore, that Reid shows a gap to exist in the theory, his result remains 'negative.' The philosopher will say that it is not enough to assert a principle dogmatically without showing its place in a reasoned system of thought. The psychologist, on the other hand, who takes Reid's own ground, may regard the statement only as a useful challenge to further inquiry. The analysis hitherto given may be insufficient, but where Reid has failed, other inquirers may be more successful. As soon, in fact, as we apply the psychological method, and regard the 'philosophy of mind' as an 'inductive science,' it is perilous, if not absolutely inconsistent, to discover 'intuitions' which will take us beyond experience. The line of defence against empiricism can only be provisional and temporary. In his main results, indeed, Reid had the advantage of being on the side of 'common sense.' Everybody was already convinced that there were sticks and stones, and everybody is prepared to hear that their belief is approved by philosophy. But a difficulty arises when a similar method is applied to a doctrine sincerely disputed. To the statement, 'this is a necessary belief,' it is a sufficient answer to reply, 'I don't believe it,' In that case, an intuition merely amounts to a dogmatic assumption that I am infallible, and must be supported by showing its connection with beliefs really universal and admittedly necessary.
Dugald Stewart followed Reid upon this main question, and with less force and originality represents the same point of view. He accepts Reid's view of the two co-ordinate departments of knowledge; the science of which mind, and the science of which body, is the object. Philosophy is not a 'theory of knowledge' or of the universe; but, as it was then called, 'a philosophy of the human mind.' 'Philosophy' is founded upon inductive psychology; and it only becomes philosophy in a wider sense in so far as we discover that as a fact we have certain fundamental beliefs, which are thus given by experience, though they take us in a sense beyond experience. Jeffrey, reviewing Stewart's life of Reid, in the Edinburgh Review of 1804, makes a significant inference from this. Bacon's method, he said, had succeeded in the physical sciences, because there we could apply experiment. But experiment is impossible in the science of mind; and therefore philosophy will never be anything but a plaything or a useful variety of gymnastic. Stewart replied at some length in his Essays,[168] fully accepting the general conception, but arguing that the experimental method was applicable to the science of mind. Jeffrey observes that it was now admitted that the 'profoundest reasonings' had brought us back to the view of the vulgar, and this, too, is admitted by Stewart so far as the cardinal doctrine of 'the common sense' philosophy, the theory of perception, is admitted.