A Short History of Modern Philosophy: From Descartes to Wittgenstein

by Roger Scruton

  Indeed, by extending his naturalism into the realm of ethics, Hume produced a moral philosophy which contains an interesting and to some extent credible answer to moral scepticism. The sceptic supposes that nothing holds sway in the human heart besides its own emotions, and that we each pursue our own goals, resisting those who impede us.

  Morality is merely a fiction, with which we try to hoodwink those who stand between us and our prize. In fact, Hume argues, this picture entirely misrepresents our nature as social beings. There are occasions when we are not in the grip of passion, when our goals recede from view and when we contemplate the human world from a position of detached curiosity. This happens when we read a story, a tragedy or a work of history. It happens too when others set their case before us, as in a court of law, and solicit our judgement. In such cases our passions are stirred not on our own behalf, but on behalf of another. This movement of sympathy is natural to human beings and informs all their perceptions of the social world. Moreover, it tends always in the same direction. Whatever our goals, you and I can agree once we have learned to discount them. If two parties to a dispute come before us, then we shall tend to agree in our verdict, provided the facts are clear and provided neither you nor I have a personal interest in the outcome. This discounting of personal interest leaves an emotional vacuum which only sympathy can fill. And sympathy, being founded in our common nature, tends to a common conclusion.

  Such is the origin of morality for Hume: the disposition that we all have, to discount our interests and reflect impartially on the world. Although the resulting passions are faint compared with our selfish desires, they are steady and durable. Moreover, they are reinforced by the agreement of others, so that, collectively, our moral sentiments provide a far stronger force than any individual passion and lead to the kind of public constraints on conduct that are embodied in custom and law.

  And here lies the justification for Hume’s claim that reason ought to be the slave of the passions. For if we assign to reason the final authority in matters of moral judgement, we shall be driven to scepticism, upon discovering that reason has no competence in the matter. Here as elsewhere reason must give way to custom, as the final guide to human life and the embodiment of our human nature.

  God and free will

  In his posthumously published Dialogues Concerning Natural Religion, Hume demolishes to his satisfaction what he considers to be the principal arguments for the existence of God. His professed aim is once again to curtail the pretensions of reason and put instinct in their place. But his subdued protestation of a ‘faith’ that needs to be safeguarded from the absurdities of metaphysical speculation has seldom been read as other than ironical. Hume was well known among his contemporaries for his scepticism towards the idea of an afterlife. He is reputed to have found nothing more absurd in the idea that he should cease to exist on dying than in the idea that he began to exist at birth. Two vast periods of Humelessness stretch before and after him—and why should he be concerned by either?

  In a famous essay, and again in the first Enquiry, Hume also mounted an argument, of which he was particularly proud, despite the fact that it had been anticipated by Spinoza, to show that belief in miracles is always irrational. The very laws of nature which suffice to summarise our knowledge of reality constitute the strongest possible evidence against the testimony of those who bear witness to miracles. For a miracle is, by definition, a violation of a law of nature, and is therefore ruled out by the rest of our scientific knowledge.

  In the matter of human freedom, however, Hume appears once again in his irenic character. He held that there is in fact no contradiction between the belief that we are free and the belief that nature (including human nature) is governed by immutable and universal laws. If we examine the idea of freedom, he argued, we shall find in it nothing that supposes the abrogation of natural laws. For freedom does not mean the absence of causation. Rather, it is ‘the power of acting or not acting, according to the determinations of the will; that is, if we choose to remain at rest, we may; if we choose to move, we also may.’ Even if the universe is a fully deterministic system and human beings are governed by the laws that determine everything else, this does not contradict the belief that we have this power to act, according to the determination of the will. Indeed, the very definition of freedom shows that free will presupposes causality and therefore does not deny it. What has been thought to be a philosophical problem is no problem at all, but a metaphysical illusion caused by the failure to define our terms. This ‘compatibilist’ solution to the problem of free will has been greatly influential, even though few would now adopt it in the simple form put forward by Hume. Hume’s ‘dissolution’ of a traditional metaphysical question shows him attempting to remove rather than to create intellectual perplexity, over a matter where he regarded perplexity to be not natural, but artificial.

  If Hume’s philosophy is purified of its attachment to discredited theories of meaning and outmoded psychology, we can see in it a remarkable derivation of the consequences of the Cartesian doubt. Combining Descartes’ emphasis on epistemology and the first person with a rigorous empiricism, Hume found himself successively breaking down our common-sense claims to objective knowledge. The consequent retreat into the confines of the first person was accompanied by no thread of reasoning that would enable him to emerge from there except by appeal to custom and instinct. Even the sphere of the subject is thrown in doubt when, as is almost inevitable for a philosophy which consistently questions all propositions that cannot be translated into empirical terms, the concept of substance is abandoned. Hume finds himself trapped within the sphere of his own experience without even the assurance of a self to whom that experience belongs. The loss of the object seems to bring the loss of the subject in its train. Kant perceived this, and perceived the ultimate incoherence in a philosophy which elevates subjective experience into the sole basis of knowledge, while demolishing the idea of the subject. He therefore sought to reverse Hume’s argument and to show that the very supposition of a realm of subjective knowledge already involves the covert affirmation of everything Hume had sought to deny. It is to the Kantian enterprise that we now must turn. We may then see the full historical significance of Hume.

  Part Three - Kant and idealism

  10 - KANT I: THE CRITIQUE OF PURE REASON

  We have traced two contrasting philosophical currents, rationalism and empiricism, from their common inception in the ‘cogito’ of Descartes, to their final divergence in Leibniz and Hume. In the eighteenth century, the century of Enlightenment, it was between those two philosophies that a thinking person had to choose. It was Kant’s principal contribution to show that the choice between empiricism and rationalism is unreal, that each philosophy is equally mistaken, and that the only conceivable metaphysics that could commend itself to a reasonable being must be both empiricist and rationalist at once.

  Immanuel Kant (1724-1804) lived and taught at Königsberg, then in Prussia (but now part of Russia). His early works (known as the ‘pre-critical’ writings) were followed by a period of silence (1770-1781) and then by the first of the three great Critiques—the Critique of Pure Reason (1781, second edition 1787). This dealt in a systematic way with the entire field of epistemology and metaphysics; it was followed by the Critique of Practical Reason (1788), concerned with ethics, and the Critique of Judgement (1790), concerned largely with aesthetics. Among Kant’s other works, the most important are the Prolegomena to any Future Metaphysics (1783) and The Foundation of the Metaphysic of Morals (1785), the first being a popular exposition of his mature metaphysics, the second of his lifelong stance towards morality. His writings on logic, jurisprudence and political philosophy have been less influential, although Hegel’s political transformation of the Critique of Practical Reason has had an incalculable effect on subsequent political thought and practice.

  Of diminutive stature and austere habits, Kant was nevertheless a gregarious man, a brilliant talker, and a loved a
nd respected member of social and literary circles. He was a founding spirit of the German Romantic movement which was to change the consciousness of Europe, and also the father of nineteenth-century idealism. He was (and remains) the greatest philosopher since Aristotle, and his most important book— the Critique of Pure Reason—is of an intellectual depth and grandeur that defy description. Mme de Staël wrote of it thus:

  His treatise on the nature of the human understanding, entitled the 'Examination of Pure Reason', appeared nearly thirty years ago, and this work was for some time unknown; but when at length the treasures of thought which it contains were discovered, it produced such a sensation in Germany, that almost all which has been accomplished since in literature as well as in philosophy, has flowed from the impulse given by this performance.

  I shall devote this chapter to a discussion of that work, leaving the ethics, the aesthetics and the vagaries of Kant’s immediate influence to the chapter which follows.

  Kant’s early philosophical inspiration had been the system of Leibniz, as expounded by Wolff (see chapter 6). But despite this influence—which is everywhere apparent in the Critique of Pure Reason—Kant’s philosophy is unique, both in its methods and in its aims. In order to understand those aims we must again consider the impact, during the seventeenth and eighteenth centuries, of the rise of science. Science presented itself as a universal discipline, the premises of which were certain, and the methods of which were disputable only by the adoption of a stance of philosophical scepticism. No one could engage in science without accepting both the established results of his predecessors, and also the empirical methods that led to their discovery. Science presented a picture of unanimity and objectivity which no system of metaphysics could rival. Forced by this fact into unnatural self-consciousness, philosophy found itself with no results that it could offer as its own peculiar contribution to the fund of human knowledge. The very possibility of metaphysics was thrown in doubt, and this doubt was only exacerbated by Hume’s radical scepticism—a scepticism which, according to Kant, aroused him from his ‘dogmatic [by which he meant Leibnizian] slumbers’. All philosophy, then, for Kant, must begin from the question ‘How is metaphysics possible?’

  In answer to that question, Kant attempted a systematic critique of human thought and reason. He tried to explore not just scientific beliefs, but all beliefs, in order to establish exactly what is presupposed in the act of belief as such. He wished to describe the nature and limits of knowledge, not just in respect of scientific discovery, but absolutely: his metaphysics was designed, not as a postscript to physics, but as the very foundation of discursive thought. He hoped to show three things:

  That there is a legitimate employment of the understanding, the rules of which can be laid bare, and that limits can be set to this legitimate employment. (It is a striking conclusion of Kant’s thought that rational theology is not just unbelievable, but unthinkable.)

  That Humean scepticism is impossible, since the rules of the understanding are already sufficient to establish the existence of an objective world obedient to a law of causal connection.

  That certain fundamental principles of science—such as the principle of the conservation of substance, the principle that every event has a cause, the principle that objects exist in space and time, can be established a priori.

  Kant’s proof of these contentions begins from the theory of ‘synthetic a priori’ knowledge. According to Kant, scientific knowledge is a posteriori: it arises from, and is based in, actual experience. Science, therefore, deals not with necessary truths but with matters of contingent fact. However, it rests upon certain universal axioms and principles, which, because their truth is presupposed at the start of any empirical enquiry, cannot themselves be empirically proved. These axioms are, therefore, a priori, and while some of them are ‘analytic’ (true by virtue of the meanings of the words used to formulate them), others are ‘synthetic’, saying something substantial about the empirical world. Moreover, these synthetic a priori truths, since they cannot be established empirically, are justifiable, if at all, through reflection, and reflection will confer on them the only kind of truth that is within its gift: necessary truth. They must be true in any conceivable world. (Kant’s idea of necessity is here weaker than that of Leibniz, for whom necessity meant truth in every possible world; see pp. 69-70.) These truths, then, form the proper subject matter of metaphysics; the original question of metaphysics has become: ‘How is synthetic a priori knowledge possible?’

  Kant compared his answer to that question (to which he gave the vivid name ‘transcendental idealism’) to the Copernican revolution in astronomy, because, like Copernicus, he had moved away from the narrow vision which sees one thing as central, towards a wider vision from which that one thing (in this case the capacities of the human understanding) can be surveyed and criticised. There is an immediate intellectual difficulty of which Kant was aware, and which provides the explanation of the word ‘transcendental’ (a technical term which has as little to do with ‘Transcendental Meditation’ as with Liszt’s Transcendental Studies). Consider the question ‘How is logic possible?’ What argument could there be for the principles of logic that did not already presuppose them? Analogously, if the synthetic a priori principles of the understanding are as fundamental to thought as Kant asserted, then the very attempt to establish their validity must at the same time assume them. It was for this reason that Kant called his philosophical method ‘transcendental’, since it contained an attempt to transcend through argument what argument must presuppose. Not surprisingly, the possibility of such ‘transcendental argument’ has been the object of continual scepticism. Nevertheless, the individual conclusions of the Critique of Pure Reason are of such interest, and often of such intrinsic plausibility, that Kant’s own theory as to the nature of his method has dissuaded only the most fatuously common-sensical from trying to reconstruct his argument.

  Kant believed that neither the empiricists nor the rationalists could provide a coherent theory of knowledge. The first, who elevate experience over understanding, deprive themselves of the concepts with which experience might be described (for no concept can be derived as a mere ‘abstraction’ from experience); while the second, who emphasise understanding at the expense of experience, deprive themselves of the very subject matter of knowledge. Knowledge is achieved through a synthesis of concept and experience, and Kant called this synthesis ‘transcendental’, meaning that it could never be observed as a process, but must always be presupposed as a result. Synthetic a priori knowledge is possible because we can establish that experience, if it is to be subject to this synthesis, must conform to the ‘categories’ of the understanding. These categories are the basic forms of thought, or a priori concepts, under which all merely empirical concepts are subsumed. (For example, the concept ‘table’ is subsumed under ‘artifact’, which in turn is subsumed under ‘object’ and hence under ‘substance’; the concept of ‘killing’ is subsumed under ‘action’, which falls under ‘cause’. The categories are the end-points of these chains of subsumption, points beyond which one cannot proceed, since they represent the most basic operations of human thought.) Thus we can know a priori that our world (if it is to be our world) must obey certain principles, principles implicit in such concepts as substance, object and cause, and that it must fall under the general order of space and time.

  The cornerstone of this anti-sceptical proof occurs in a famous, but extremely obscure, passage of the Critique of Pure Reason, known as ‘The Transcendental Deduction of the Categories’. This exists in two versions, corresponding to the two editions of the Critique of Pure Reason, and it is hard to say which version is to be preferred, since neither is fully intelligible. But the outline of the argument can be displayed, and it can be seen that, if valid, it is one of the most important arguments in the whole of philosophy.

  Like Descartes, Kant begins from an examination of an aspect of selfconsciousness. But, unlike Descartes, he us
es his arguments in order to reject what I have called ‘the priority of the first person’. In other words, he removes the privileges from subjectivity, and in doing so destroys the possibility of an empiricist theory of the mind. The immediate result is that epistemology becomes secondary to metaphysics; for without metaphysics the deliverances of the senses become impossible to describe.

  Kant’s near contemporary Lichtenberg remarked that Descartes should have said not, ‘I think’, but only, ‘It thinks in me’. However, as Kant recognised, there is contained in the idea of a thought, as of every mental content, the notion of a subject. Moreover, this subject has an immediate and intuitive apprehension of its own unity: I know immediately of my present mental states that they are mine, and in the normal case I cannot be wrong about this. (In other words, in the case of the present contents of the mind, the distinction between being and seeming evaporates. This is what is meant by the ‘subjectivity’ of the first person.) It is impossible that I should be in the position of Mrs Gradgrind (in Hard Times), who, on her deathbed, knew only that there was a pain in the room somewhere, but not that it was hers. Nor do I have to find out that my pain and my thought belong to a single consciousness. My having these states presupposes my ability to assign them to the single subjective unity of the self.