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Sidgwick on Kant

by Soshichi Uchii

Sidgwick on Kant

(1) On Kant's derivation of duties from the categorical imperative

It is well known that Sidgwick's principle of justice owes at least a part of its content to Kant's categorical imperative. However, even where he acknowldges this, Sidgwick is quite critical to Kant's whole project of ethics based on the categorical imperative. For example, in a preliminary discussion of the principle of justice, Sidgwick argues as follows:

... if we ask ourselves whether we believe that any similar person in similar circumstances ought to perform the contemplated action, the question will often disperse the false appearance of rightness which our strong inclination has given to it. We see that we should not think it right for another, and therefore that it cannot be right for us. Indeed this test of the rightness of our volitions is so generally effective, that Kant seems to have held that all particular rules of duty can be deduced from the one fundamental rule "Act as if the maxim of thy action were to become by thy will a universal law of nature". But this appears to me an error analogous to that of supposing that Formal Logic supplies a complete criterion of truth. (The Methods of Ethics, bk.iii, ch. i, p. 209-210; to be precise, the rule Sidgwick refers to is the "formula of the law of nature" of the categorical imperative.)

The reason why Sidgwick does not agree with Kant is very clearly stated in several places in The Methods of Ethics. First in general terms, he says that, although a volition which does not stand this test is to be condemned, "a volition which does stand it may after all be wrong" (p. 210). I think this is perfectly right, and it seems quite strange that eminent Kantian scholars such as H. J. Paton do not refer to this criticism (see, for instance, Categorical Imperative, p. 152); presumably many Kantians just disregard what a utilitarian says!

Moreover, Sidgwick later goes on to a more specific criticism, which any serious student of Kant must consult. At the end of chapter xiii (where the three self-evident principles are stated), book iii, Sidgwick added a long note on Kant, arguing against Kant's "deduction", from the categorical imperative, of the duty of promoting the happiness of others (Kant's Grundlegung, ch. 2, the fourth example of the application of the formula of the law of nature). According to Kant, the maxim that each should be left to take care of himself without either aid or intereference, can be a universal law, since it does not contain a contradiction; but Kant argues that it would be impossible for us to will it to be a universal law.

Thus Sidgwick quotes from Kant, "A will that resolved this would be inconsistent with itself, for many cases may arise in which the individual thus willing needs the benevolence and sympathy of others". Futher, Sidgwick refers also to passages from Metaphysik der Sitten (Metaphysische Angangsgruende der Tugendlehre) that "the Self-love which necessarily exists in every one involves the desire of being loved by others and receiving aid from them in case of need" (The Methods of Ethics, 389). Thus, according to Kant, we regard ourselves as an end for others and claim that they should contribute to our own happiness; then why should we not recognize, according to the categorical imperative, the duty of making their happiness our end? (ibid.)

But Sidgwick argues that such reasonings are invalid.

In the first place, that every man in need wishes for the aid of others is an empirical proposition which Kant cannot know a priori. We can certainly conceive a man in whom the spirit of independence and the distaste for incurring obligations would be so strong that he would choose to endure any privations rather than receive aid from others. But even granting that every one, in the actual moment of distress, must necessarily wish to the assistance of others; still a strong man, after balancing the chances of life, may easily think that he and such as he have more to gain, on the whole, by the general adoption of the egoistic maxim; benevolence being likely to bring them more trouble than profit. (ibid.)

I can find no flaw in this argument; Sidgwick is right and Kant wrong. Moreover, Sidgwick is fair to Kant in that he does not disregard another argument by Kant for deriving the same conclusion, where Kant presents the formula of the end in itself. In order to show the fairness and clearness of Sidgwick's exposition, let me quote.

He lays down that, as all action of rational beings is done for some end, there must be some absolute end, corresponding to the absolute rule before given, that imposes on our maxims the form of universal law. This absolute end, prescribed by Reason necessarily and a priori for all rational beings as such, can be nothing but Reason itself, or the Universe of Rationals; for what the rule inculcates is, in fact, that we should act as rational units in a universe of rational beings ... Or again, we may reach the same result negatively. For all particular ends at which men aim are constituted such by the existence of impulses directed towards some particular objects. Now we cannot tell a priori that any one of these special impulses forms part of the consitution of all men: and therefore we cannot state it as an absolute dictate of Reason that we should aim at any such special object. If, then, we thus exclude all particular empirical ends, there remains only the principle that "all Rational beings as such are ends to each": or, as Kant sometimes puts it, that "humanity exists as an end in itself." (389-390)

Notice that Kant substituted "humanity" for "Reason" in the preceding argument. And because of this, Kant could argue as follows (Sidgwick's paraphrasing): "so long as I confine myself to mere non-interference with others, I do not positively make Humanity my end; my aims remain selfish, though restricted by this condition of non-interference with others. My action, therefore, is not truly virtuous; for Virtue is exhibited and consists in the effort to realize the end of Reason in opposition to mere selfish impulses" (390). And therefore, in Grundlegung, Kant concluded that "the end of the subject, which is itself an end, must of necessity be my ends, if the representation of Humanity as an end in itself is to have its full weight with me."

Now Sidgwick is quick to point out that the conception of "humanity as an end in itself" is perplexing. And Sidgwick's decisive criticism is this:

there seems to be a sort of paralogism in the deduction of the principle of Benevolence by means of this conception. For the humanity which Kant maintains to be an end in itself is Man (or the aggregate of men) in so far as rational. But the subjective ends of other men, which Benevolence directs us to take as our own ends, would seem, according to Kant's own view, to depend upon and correspond to their non-rational impulses---their empirical desires and aversions.

As Sidgwick points out, it is hard to see why, if man as a rational being is an absolute end to other rational beings, they must regard his subjective aims which are determined by his non-rational impulses as their own ends. Thus Kant's attempt to derive the duty of benevolence (or kindness or whatever) is decisively refuted by Sidgwick. I may add that I find none of Kant's derivation of duties from the categorical imperative in Grundlegung convincing (see Uchii 1988, sect. 49).

(2) On Kant's Conception of Free Will

Another important contribution Sidgwick made in the study of Kant is his criticism of Kant's conception of Free Will (originally in Mind 13, 1888; reprinted as Appendix in The Methods of Ethics. A brief reference to this criticism is also made in Sidgwick 1902, 274, note 1).

Sidgwick distinguishes three conceptions of Freedom. (1) Good or Rational Freedom, which means that a man is free in proportion as he acts in accordance of Reason; (2) Neutral or Moral Freedom, which means that a man is free to choose between good and evil; (3) Capricious Freedom, which means that a man is free in so far as he has a power of acting without a motive.

And Sidgwick's main contention is that while Kant expressly repudiated Capricious Freedom and adopted Rational Freedom, he actually uses Neutral Freedom as well as Rational Freedom. But what is wrong with using these two conceptions? Well, Sidgwick says (correctly) that, in some cases at least, the two conceptions are incompatible: "if we say that a man is a free agent in proportion as he acts rationally, we cannot also say, in the same sense of the term, that it is by his free choice that he acts irrationally when he does so act" (The Methods of Ethics, 511). Thus, if Kant turns out to use both conceptions (1) and (2), Kant's theory of ethics may well contain grave inconsistencies.

Now, according to Sidgwick, Kant uses the conception of Neutral Freedom wherever he has to connect the notion of Freedom with that of Moral Responsibility (513); for if a free man makes a wrong choice (that is, choice against a moral law or a dictate of Reason), we wish to ask his responsibility, and we also wish to prevent him from shifting his responsibility on to causes beyond his control; "free" in this context clearly presupposes Neutral Freedom. Moreover, Kant's appeal to Neutral Freedom is contained in a very essential part of his ethics. Kant presents his metaphysical solution of Free Will and physical causality in terms of the distinction between "noumenon" and "phenomenon". According to him, every action regarded as a phenomenon determined in time, must be regarded as a necessary result of determining causes in antecedent time; but it may be also regarded in relation to the agent considered as a thing-in-itself, as the "noumenon" of which the action is a phenomenon. Since this "noumenon" is not subject to causality-in-time, "nothing is antecedent to the determination of his will" and "every action ... even the whole series of his existence as a sensible being, is in the consciousness of his supersensible existence nothing but the result of his causality as a noumenon" (quoted from Sidgwick, 513. Kant's original is in Kritik der praktischen Vernunft, I.i.3, Kritische Beleuchtung der Analytik). Sidgwick's point of quoting this passage is this:

my point is that if we accept this view of Freedom at all, it must obviously be Neutral Freedom: it must express the relation of a noumenon that manifests itself as a scoudrel to a series of bad volitions, in which the moral law is violated, no less than the relation of a moumenon that manifests itself as a saint to good or rational volitions, in which moral law or categorical imperative is obeyed. (ibid.)

As Sidgwick succinctly points out, Kant's quoted passages appear in the context where Kant raises the question "How a man who commits a theft can be called free at the moment of committing it?" Thus Kant clearly presupposes Neutral Freedom in relation to moral responsibility, moral imputation, or the judicial sentences of conscience.

As regards the conception of Rational Freedom in Kant, we need not say too much, because this is what Kant expressly advocates in many places. In a word, Kant's "official view" is that a free will and a will subject to moral laws are one and the same, and Reason dictates these laws. But, then, we have plain contradictions in Kant's ethics. As we have already seen, a man who committs a theft is free in the sense of Neutral Freedom; but he must be, at the same time, as a rational being, free in the sense of Rational Freedom, which means that he is bound to obey moral laws, and refrains in particular from committing a theft. But the two conceptions of freedom is incompatible in this instance.

However, Sidgwick is quite fair to say that "I should quite admit that the most important parts both of Kant's doctrine of morality, and of his doctrine of Freedom may be saved" (515). But its cost may be quite high.

I think that the whole topic of the "heteronomy" of the will, when it yields to empirical or sensible impulses, will have to be abandoned or profoundly modified. And I am afraid that most readers of Kant will feel the loss to be serious; since nothing in Kant's ethical writing is more fascinating than the idea ... that a man realizes the aim of his true self when he obeys the moral law, whereas, when he wrongly allows his action to be determined by empirical or sensible stimuli, he becomes subject to physical causation, to laws of a brute outer world. But if we dismiss the identification of Freedom and Rationality, and accept definitely and singly Kant's other conception of Freedom as expressing the relation of the human thing-in-itself to its phenomenon, I am afraid that this spirit-stirring appeal to the sentiment of Liberty must be dismissed as idle rhetoric. (516)

All right. Lewis White Beck, another eminent Kantian scholar, refers to Sidgwick's distinction (Beck 1960, 205; he misconstrues this distinction) but completely disregards this challenge. Have any Kantian moral philosophers ever answered this challenge of Sidgwick?


Beck, Lewis White (1960) A Commentary on Kant's Critique of Practical Reason, 1960.

Kant, I. (1785) Grundlegung zur Metaphysik der Sitten, 1785.

Kant, I. (1788) Kritik der praktischen Vernunft, 1788.

Kant, I. (1797) Metaphysik der Sitten, 1797.

Paton, H.J. (1958) The Categorical Imperative, 3rd ed.

Sidgwick, H. (1902) Outlines of the History of Ethics, 5th ed. [The reader should read a clear and fair exposition of Kant's ethics on pp.271-277.]

Sidgwick, H. (1907) The Methods of Ethics, 7th ed.

Uchii, Soshichi (1988) The Law of Freedom, the Logic of Interest [in Japanese], Minerva, 1988.

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May 11, 2000; last modified April 17, 2006. (c) Soshichi Uchii