A Short History of Modern Philosophy: From Descartes to Wittgenstein, Second Edition (20 page)

in every system of morality which I have hitherto met with.the author proceeds for some time in the ordinary way of reasoning.when of a sudden I am surprised to find that, instead of the usual copulation of propositions is and is
not,
I meet with no proposition that is not connected with an
ought
or
ought not.
This change is imperceptible; but is, however, of the last consequence. For as this
ought
or
ought not
expresses some new relation or affirmation, it is necessary that it should be observed and explained; and that at the same time a reason should be given, for what seems altogether inconceivable, how this new relation can be a deduction from others which are entirely different from it.

As in his criticism of induction, Hume is here arguing that the relation between propositions which we accept and the evidence that we adduce for them is not, and cannot be, deductive. In which case, on what do we base our confidence that the ‘evidence’ provides us with any reason at all for asserting the propositions that we suppose to be grounded in it? Here the difficulty is that of finding a satisfactory relationship between propositions about what is and propositions about what ought to be. That there is no deductive relation between an ‘is’ and an ‘ought’ is a proposal which is sometimes known as Hume’s law. If true it has seemed to many that this ‘law’ must jeopardise all claims to moral knowledge and leave ethics at the mercy of subjective whim, against which no arguments can be cogently delivered.

The second difficulty that Hume discerned for the objectivity of morality is more profound and more far-reaching in its implications. This is a difficulty not for the idea of moral judgement, but for the more fundamental idea upon which moral judgement rests, the idea of practical reason. Hume denied that there could be such a thing as practical reason. For reason to be practical it is not sufficient that it be applied to practical matters; it must also be capable of generating practical conclusions. As Aristotle argued in the
Nicomachean Ethics,
practical conclusions are not thoughts but actions. Reason, in its practical employment, must therefore generate actions in just the way that, in its theoretical employment, it generates thoughts and beliefs. But how can this be so?

Actions are generated by motives, but reason alone, Hume argued, can never provide a motive to action. All reason can do is present us with a picture of the means to given ends; it cannot persuade us either to adopt those ends or to reject them. Reason is confined in its operation to matters of fact and the relations among ideas. ‘After every circumstance, every relation, is known, the understanding has no further room to operate nor any object on which it could employ itself.’ Whatever conclusions we may draw as to the way things are, we are still as far as ever from the motive to action. It is therefore ‘not contrary to reason to prefer the destruction of the whole world to the scratching of my finger’. What we take to be practical reasoning is simply the working out of the best means to the satisfaction of desires that have their origin not in reason, but in passion. Indeed, Hume goes so far as to say, ‘Reason is, and ought only to be, the slave of the passions.’ As a modern philosopher would put it, all practical reasons are relative to some antecedent desire, which is therefore the sole origin of their persuasive power. In which case, no amount of reasoning can persuade evil people (those with evil desires) to any course of action except that which already attracts them. This ethical scepticism can be seen as a further application of the thought that there can be only contingent relations between events identified at separate times. If reason could provide a motive to act, then an action could be determined by the reasoning which precedes it. But the relation between this reasoning and the action would have to be necessary, which contradicts the assumption that the action
follows
the reasoning and is distinct from it.

Why does Hume say that reason
ought
to be the slave of the passions? Surely this is hardly compatible with his far-reaching scepticism about the word ‘ought’? The answer to this is to be found in the part of Hume’s philosophy which was most obviously a product of the intellectual environment into which he grew: his theory of the moral sentiments, and of their immovable centrality in human nature. Hume insists that, despite apparent local variations, there is a basic uniformity of moral sentiment among human beings. Like the British moralists discussed in the last chapter, Hume thought that in every locality and in every period of history, people have been drawn to favour some things and disapprove of others, through the innate disposition, inseparable from human nature, to sympathise with their fellows. It is from the sentiment of sympathy, the origin and object of which lies in man’s social condition, and from the benevolence which alone makes that condition possible, that the world comes to appear to us as decked out in the colours of morality. But we should not therefore think that ‘right’ and ‘wrong’ are properties that inhere in things independently of our disposition to approve or disapprove of them. By an extension of the Lockean idea of a secondary quality, Hume argued that there is no
fact
of the matter here, other than our moral sentiments. ‘Vice and virtue...may be compared to sounds, colours, heat and cold, which are not qualities in objects, but perceptions in the mind.’ With the result that, ‘when you pronounce any action or character to be vicious you mean nothing but that from the constitution of your nature you have a feeling or sentiment of blame towards it.’

In his description of the moral sentiments Hume drew heavily on the analysis of moral feelings given by Aristotle, Hutcheson and, to some extent, Spinoza. His perception of the complexity of these feelings and his attempt to give a truthful account of their significance led to a system of ethics which mitigated his scepticism about the place of reason in determining human action. Having subverted the ‘vulgar’ systems of morality, Hume raised in their place a balanced and dispassionate picture of the good life for man. This picture was not wholly dissimilar from that already defended by Shaftesbury and Hutcheson.

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.

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.