Philosophy · Bertrand Russell
SOME GREAT PHILOSOPHIES OF THE PAST
Our discussions, hitherto, have been concerned very largely with Man, but Man on his own account is not the true subject-matter of philosophy. What concerns philosophy is the universe as a whole; Man demands consideration solely as the instrument by means of which we acquire knowledge of the universe. And that is why it is human beings as capable of knowledge that have concerned us mainly in past chapters, rather than as centres of will or of emotion. We are not in the mood proper to philosophy so long as we are interested in the world only as it affects human beings; the philosophic spirit demands an interest in the world for its own sake. But since we apprehend the world through our own senses, and think about it with our own intellect, the picture that we acquire is inevitably coloured by the personal medium through which it comes to us. Consequently we have to study this medium, namely ourselves, in order to find out, if we can, what elements in our picture of the world are contributed by us, and what elements we may accept as representative of outside fact. Previous chapters have studied cognition, both as an outwardly observable reaction, and as it appears to introspection. In the chapters that remain, we shall be concerned with what we can know about the universe, in view of the nature of the instrument that we have to employ. I do not think we can know as much as many philosophers of the past have supposed, but I think it is worth while to have in our minds an outline of their systems. I shall therefore begin by setting forth a few typical philosophical constructions of earlier centuries.
Modern philosophy is generally taken as beginning with Descartes, who flourished in the first half of the seventeenth century. We have already had occasion, in Chapter XVI, to consider his argument “I think, therefore, I am”, but now we will deal with him somewhat more generally. He inaugurated two movements, one in metaphysics, one in theory of knowledge. In metaphysics, he emphasised the gulf between mind and matter, or between soul and body; in theory of knowledge he advocated a critical scrutiny of premises. These two movements had different histories, each of them interesting. The science of dynamics was rapidly developing in Descartes’ time, and seemed to show that the motions of matter could be calculated mathematically, given sufficient data. As the motions of matter include our bodily acts, even speaking and writing, it seemed as if the consequence must be a materialistic theory of human behaviour. This consequence, however, was distasteful to most philosophers, and they therefore invented various ways of escaping from it. Descartes himself thought that the will could have certain direct physical effects. He thought that the brain contains a fluid called the “animal spirits”, and that the will could influence the direction of its motion, though not the velocity. In this way he was still able to hold that the will is effective in the manner in which common sense supposes it to be. But this view did not fit in at all well with the rest of his philosophy. He held that, apart from the Supreme Substance, namely God, there are two created substances, mind and matter; that the essence of mind is thought, and that the essence of matter is extension. He made these two substances so different that interaction between them became difficult to understand, and his followers decided that there is never any effect either of mind on matter or of matter on mind.
The motives for this development were various; perhaps the most important was the development of physics immediately after Descartes’ time. A law was discovered called the “conservation of momentum”. This states that, if a system of bodies is in any sort of motion, and is free from outside influences, the amount of motion _in any direction_ is constant. This showed that the kind of action of the will on the “animal spirits” which Descartes had assumed was contrary to the principles of dynamics. It seemed to follow that mind cannot influence matter, and it was inferred that matter cannot influence mind, since the two were regarded as co-equal substances. It was held that each goes it own way, according to its own laws. The fact that our arm moves when we will it to move was regarded as analogous to the fact that two perfectly accurate clocks strike at the same moment, though neither has any effect upon the other. The series of mental events and the series of physical events were parallel, each going at the same rate as the other, therefore they continued to synchronise, in spite of their independence of each other. Spinoza sought to make this parallelism less mysterious by denying that there are two separate substances, mind and matter. He maintained that there is only one substance, of which thought and extension are attributes. But there seemed still no good reason why the events belonging to the two attributes should develop along parallel lines. Spinoza is in many ways one of the greatest philosophers, but his greatness is rather ethical than metaphysical. Accordingly he was regarded by contemporaries as a profound metaphysician but a very wicked man.
The notion of the impossibility of interaction between mind and body has persisted down to our own day. One still hears of “psychophysical parallelism”, according to which to every state of the brain a state of mind _corresponds_ and vice versa, without either acting on the other. This whole point of view, though not exactly that of Descartes, derives from him. It has a number of sources, religious, metaphysical, and scientific; but there seems no ground whatever for regarding it as true. Take, first, the rigid determinism of traditional physics, which was to have been avoided. Spinoza rightly perceived that this could not be avoided by such methods, and therefore accepted determinism in the psychical as in the physical realm. If everything we _say_ is determined by physical causes, our thoughts are only free when we tell lies: so long as we say what we think, our thoughts also can be inferred from physics. The philosophy which I advocate escapes this consequence in several ways. In the first place, causality does not involve _compulsion_, but only a law of sequence: if physical and mental events run parallel, either may with equal justice be regarded as causing the other, and there is no sense in speaking of them as causally independent. Thus the Cartesian dualism does not have the pleasant consequences which were intended. In the second place, modern physics has become less deterministic than the physics of the past few centuries. We do not know, _e.g._ what makes a radio-active atom explode or an electron jump from a larger to a smaller orbit. In these matters we only know statistical averages.
Take next the view that mind and matter are quite disparate. This we have criticised already. It rests upon a notion that we know much more about matter than we do, and in particular upon the belief that the space of physics can be identified with the space of sensible experience. This belief is absent in Leibniz, who, however, never quite realised what his own view was. It is not absent in Kant, who realised that the space of sensible experience is subjective, and inferred that the space of physics is subjective. Since Kant, no one seems to have thought clearly about space until Einstein and Minkowski. The separation of physical and sensible space, logically carried out, shows the groundlessness of traditional views about mind and matter. This part of Descartes’ philosophy, therefore, though it accelerated the progress of physics, must be regarded as metaphysically an aberration.
The other part of Descartes’ philosophy, namely, the emphasis upon methodical doubt, and consequently upon theory of knowledge, has been more fruitful. The beginning of a philosophic attitude is the realisation that we do not know as much as we think we do, and to this Descartes contributed notably. We have seen that he set to work to doubt all he could, but found he could not doubt his own existence, which he therefore took as the starting-point of his constructive system. He supposed that the most certain fact in the world is “I think”. This was unfortunate, since it gave a subjective bias to modern philosophy. As a matter of fact, “I” seems to be only a string of events, each of which separately is more certain than the whole. And “think” is a word which Descartes accepted as indefinable, but which really covers complicated relations between events. When is an event a “thought”? Is there some intrinsic characteristic which makes it a thought? Descartes would say yes, and so would most philosophers. I should say no. Take, _e.g._ a visual and an auditory sensation. Both are “thoughts” in Descartes’ sense, but what have they in common? Two visual sensations _have_ an indefinable common quality, viz. that which makes them visual. Two auditory sensations likewise.
But a visual and an auditory sensation have in common, if I am not mistaken, no intrinsic property, but a certain capacity for being _known_ without inference. This amounts to saying that they are mnemic causes of a certain kind of event, called a cognition, and that they have moreover, a certain formal similarity to the cognition which they cause. Therefore, instead of taking the general “I think” as our basis, we ought to take the particular occurrences which are known without inference, among which sensations (or rather “perceptions”) will be included. These occurrences, as we have already seen, may be regarded with equal justice as physical and mental: they are parts of chains of physical causation, and they have mnemic effects which are cognitions. The former fact makes us call them physical, the latter mental, both quite truly. It is the particular events which are certain, not the “I think” which Descartes made the basis of his philosophy. It is not correct to regard the ultimate certainties as “subjective”, except in the sense that they are events in that part of space-time in which our body is--and our mind also, I should say.
A new turn was given to the Cartesian type of metaphysics by Leibniz (1646–1716), who, like Descartes, was supremely eminent both in mathematics and in philosophy. Leibniz rejected the view that there is only one substance, as Spinoza held, or only two other than God, as the orthodox followers of Descartes maintained. He also rejected the dualism of mind and matter, holding that there are innumerable substances all in a greater or less degree mental, and none in any degree material. He maintained that every substance is immortal, and that there is no interaction between one substance and another--this last being a view derived from the Cartesian independence of mind and matter. He also extended to his many substances the belief in parallelism which had existed for the two substances of the Cartesians. He called his substances “monads”, and maintained that every monad mirrors the universe, and develops along lines which correspond, point by point, with those along which every other monad is developing. A man’s soul or mind is a single monad, while his body is a collection of monads, each mental in some degree, but less so than the monad which is his soul. Inferior monads mirror the world in a more confused way than higher ones do, but there is some element of confusion in the perceptions of even the most superior monads. Every monad mirrors the world from its own point of view, and the difference between points of view is compared to a difference of perspective. “Matter” is a confused way of perceiving a number of monads; if we perceived clearly, we should see that there is no such thing as matter.
Leibniz’s system had great merits and great demerits. The theory that “matter” is a confused way of perceiving something non-material was an advance upon anything to be found in his predecessors. He had, though only semi-consciously, the distinction between physical and perceptual space: there is space in each monad’s picture of the world, and there is also the assemblage or pattern of “points of view”. The latter corresponds to what I have called “physical space”, the former to “perceptual space”. Leibniz maintained, as against Newton, that space and time consists only of relations--a view which has achieved a definitive triumph in Einstein’s theory of relativity. The weak point of his system was what he called the “pre-established harmony”, in virtue of which all the monads (so to speak) kept step, in spite of the fact that they were “windowless” and never acted upon each other. Perception, for Leibniz, was not an effect of the object perceived, but a modification arising in the perceiving monad and running parallel with what was happening in the perceived object. This view would never have seemed plausible but for the anterior Cartesian theory of the mutual independence of mind and matter. And if Leibniz himself developed, as he believed, in complete independence of all other created things, it is not clear what good reasons he could have had for believing in the existence of anything except himself, since, by his own theory, his experiences would remain unchanged if everything else were annihilated. In fact, he was only able to refute this possibility by bringing in theological considerations, which, whether valid or not, are out of place in philosophy. For this reason, his doctrines, ingenious as they were, found little acceptance in France and England, though in Germany they prevailed, in a modified form, until the time of Kant.
The systems of Descartes, Spinoza and Leibniz have one very important characteristic in common, namely, that they all depend upon the category of “substance”. This is a concept which has developed out of the common-sense notion of “thing”. A “substance” is that which has qualities, and is in general supposed to be indestructible, though it is difficult to see why. It acquired its hold over metaphysicians partly because both matter and the soul were held to be immortal, and partly through a hasty transference to reality of ideas derived from grammar. We say “Peter is running”, “Peter is talking”, “Peter is eating”, and so on. We think that there is one entity, Peter, who does all these things, and that none of them could be done unless there were someone to do them, but that Peter might quite well do none of them. Similarly we assign qualities to Peter: we say he is wise and tall and blond and so on. All these qualities, we feel, cannot subsist by themselves in the void, but only when there is a subject to which they belong; but Peter would remain Peter even if he became foolish and short and dyed his hair. Thus Peter, who is regarded as a “substance”, is self-subsistent as compared with his qualities and states, and he preserves his substantial identity throughout all sorts of changes. Similarly in the material world an atom is supposed (or rather was supposed until recently) to preserve its identity throughout all time, however it might move and whatever combinations it might form with other atoms. The concept of “motion”, upon which all physics seemed to depend, was only strictly applicable to a substance which preserves its identity while changing its spatial relations to other substances; thus “substance” acquired an even firmer hold upon physics than upon metaphysics.
Nevertheless, the notion of “substance”, at any rate in any sense involving permanence, must be shut out from our thoughts if we are to achieve a philosophy in any way adequate either to modern physics or to modern psychology. Modern physics, both in the theory of relativity and in the Heisenberg-Schrödinger theories of atomic structure, has reduced “matter” to a system of events, each of which lasts only for a very short time. To treat an electron or a proton as a single entity has become as wrong-headed as it would be to treat the population of London or New York as a single entity. And in psychology, equally, the “ego” has disappeared as an ultimate conception, and the unity of a personality has become a peculiar causal nexus among a series of events. In this respect, grammar and ordinary language have been shown to be bad guides to metaphysics. A great book might be written showing the influence of syntax on philosophy; in such a book, the author could trace in detail the influence of the subject-predicate structure of sentences upon European thought, more particularly in this matter of “substance”. And it must be understood that the same reasons which lead to the rejection of substance lead also to the rejection of “things” and “persons” as ultimately valid concepts.
I say “I sit at my table”, but I ought to say: “One of a certain string of events causally connected in the sort of way that makes the whole series that is called a ‘person’ has a certain spatial relation to one of another string of events causally connected with each other in a different way and having a spatial configuration of the sort denoted by the word ‘table’”. I do not say so, because life is too short; but that is what I should say if I were a true philosopher. Apart from any other grounds, the inadequacy of the notion of “substance” would lead us to regard the philosophy of Descartes, Spinoza, and Leibniz as incompatible with modern science. There is of course in all three, a great deal that does not depend upon “substance”, and that still has value; but “substance” supplied the framework and a good deal of the argumentation, and therefore introduces a fatal defect into these three great systems. I come now to the triad of British philosophers, Locke, Berkeley, and Hume--English, Irish, and Scotch respectively. Perhaps from patriotic bias or from community of national temperament, I find more that I can accept, and regard as still important, in the writings of these three than in the philosophy of their continental predecessors. Their constructions are less ambitious, their arguments more detailed, and their methods more empirical; in all these respects they show more kinship with the modern scientific outlook. On the other hand, Locke and Hume, if not Berkeley, approach philosophy too exclusively from the side of psychology, and are concerned to study Man rather than the universe.
Locke was a contemporary and friend of Newton; his great book, _An Essay concerning Human Understanding_, was published at almost the same moment as Newton’s _Principia_. His influence has been enormous, greater, in fact, than his abilities would seem to warrant; and this influence was not only philosophical, but quite as much political and social. He was one of the creators of eighteenth century liberalism: democracy, religious toleration, freedom of economic enterprise, educational progress, all owe much to him. The English Revolution of 1688 embodied his ideas; the American Revolution of 1776 and the French Revolution of 1789 expressed what had grown, in a century, out of his teaching. And in all these movements, philosophy and politics went hand in hand. Thus the practical success of Locke’s ideas has been extraordinary.
When, knowing all this, one comes to read Locke himself, it is difficult to resist a feeling of disappointment. He is sensible, enlightened, minute, but uninspired and (to moderns) uninspiring. One has to remember that his contemporaries found common sense exhilarating after a century of wars of religion and a long struggle with obscurantism. Locke combatted the doctrine of “innate ideas”, according to which we learned only certain things by experience, but possessed our abstract knowledge in virtue of our congenital constitution. He regarded the mind at birth as a wax tablet, upon which experience proceeded to write. Undoubtedly he was, in this matter, more in the right than his opponents, although the terms in which the controversy was waged are not such as a modern could employ. We should say that the innate apparatus of man consists of “reflexes” rather than “ideas”; also that our sense-organs, our glands, and our muscles lead to responses of certain kinds, in which our own organisation plays a part of the same importance as that played by the external stimulus. The element in our knowledge-responses that corresponds to our own bodily organisation might, perhaps, be regarded as representing what Locke’s opponents meant by “innate”. But it does not represent this at all accurately so far as our feelings towards it are concerned. The “innate” ideas were the ideas to be proud of; they embraced pure mathematics, natural theology, and ethics. But nobody is proud of sneezing or coughing. And when Locke tried to show, in detail, how our knowledge is generated by experience, he was liberating philosophy from a great deal of useless lumber, even if his own doctrines were not altogether such as we can now accept.
Locke used his own principles only in ways consistent with common sense; Berkeley and Hume both pushed them to paradoxical conclusions. The philosophy of Berkeley, to my mind, has not received quite the attention and respect that it deserves--not that I agree with it, but that I think it ingenious and harder to refute than is often supposed. Berkeley, as everyone knows, denied the reality of matter, and maintained that everything is mental. In the former respect I agree with him, though not for his reasons; in the latter respect, I think his argument unsound and his conclusion improbable, though not certainly false. However, I will leave the development of my own views to a later chapter, and confine myself to Berkeley’s argument. Berkeley contended that when, for example, you “see a tree”, all that you really _know_ to be happening is in you, and is mental. The colour that you see, as Locke had already argued, does not belong to the physical world, but is an effect upon you, produced, according to Locke, by a physical stimulus. Locke held that the purely spatial properties of perceived objects really belong to the objects, whereas such things as colour, softness, sound, etc., are effects in us. Berkeley went further, and argued that the spatial properties of perceived objects are no exception. Thus the object perceived is composed entirely of “mental” constituents, and there is no reason to believe in the existence of anything not mental. He did not wish to admit that a tree ceases to exist when we do not look at it, so he maintained that it acquires permanence through being an idea in the mind of God. It is still only an “idea”, but not one whose existence depends upon the accidents of our perceptions.
The real objection to Berkeley’s view is rather physical than metaphysical. Light and sound take time to travel from their sources to the percipient, and one must suppose that something is happening along the route by which they travel. What is happening along the route is presumably not “mental”, for, as we have seen, “mental” events are those that have peculiar mnemic effects which are connected with living tissue. Therefore, although Berkeley is right in saying that the events we know immediately are mental, it is highly probable that he is wrong as to the events which we infer in places where there are no living bodies. In saying this, however, we are anticipating the results of a fuller discussion in a later chapter. Hume, proceeding from a starting-point essentially similar to that of Locke and Berkeley, arrived at conclusions so sceptical that all subsequent philosophers have shied away from them. He denied the existence of the Self, questioned the validity of induction, and doubted whether causal laws could be applied to anything except our own mental processes. He is one of the very few philosophers not concerned to establish any positive conclusions. To a great extent, I think, we must admit the validity of his reasons for refusing to feel the usual certainties. As regards the Self, he was almost certainly right. As we have already argued, a person is not a single entity, but a series of events linked together by peculiar causal laws. As regards induction, the question is very difficult, and I shall devote a subsequent chapter to it. As regards causal laws, the question, as we shall find later, is the same as the question of induction. On both points Hume’s doubts are not to be lightly dismissed.
Ideas discussed in this chapter
Text from Project Gutenberg, public domain in the United States.