Metaphysics has as the proper end of its investigation only three ideas: God, freedom, and immortality … (B395n.)Footnote
1
Frederick Rauscher’s Naturalism and Realism in Kant’s Ethics
Footnote
2
is a bold and well-written interpretation of Kant’s practical philosophy, one that exhibits a mastery not only of Kant’s own texts (his published works as well as his extensive lectures, notes and fragments), but also the flourishing secondary literature on Kant as well as relevant currents in contemporary philosophy – particularly as regards the central topics of naturalism and realism. But despite (and, I suspect, also to a certain extent because of) Rauscher’s intimate familiarity with Kant’s texts, there is a formidable methodological warning issued near the beginning of the book that makes critical discussion of its main theses difficult. For Rauscher is ‘not providing a strictly exegetical work’, and he acknowledges that there are ‘passages in Kant’s writings that are inconsistent with elements of … [his] interpretation’ (p. 5). Nor does he claim ‘to have presented precisely the historical Kant’s position’ (p. 242). Rather, Rauscher believes he has offered ‘an interpretation that encompasses the main claims in Kant’s ethics and shows how Kant either did or could have, using the resources available within his practical philosophy, presented an entirely metaphysically naturalistic ethics’ (p. 242). Fair enough. But is there sufficient consensus concerning what the ‘main claims in Kant’s ethics’ are and what these claims mean and imply for the tribunal of reason to conduct a fair trial and issue its judgement (see Axi–xii; for discussion, see O’Neill Reference O’Neill1989: 3–28)? I am honestly not sure. Additionally, there is the pragmatic constraint imposed by the editors of Kantian Review on each of the participants in this particular tribunal to adhere to their respective word limits. But if consensus regarding Kant’s main claims in ethics does not yet exist, is it likely to be attained in the space of a few pages?
In what follows I will concentrate on some of Kant’s main claims about God, freedom and immortality, key concepts which – according to both Kant and Rauscher – properly belong ‘not to physics, that is, to speculative reason, but to morals’ (KpV, 5: 140; cf. 138), but which – or so I shall argue – do not belong to morals in the thin way that Rauscher envisages. I am focusing on these three perennial topics in part because I believe they illustrate concretely what many readers will find most problematic about Rauscher’s book – namely, its defence of the claim that Kant can and should be read as a ‘metaphysical naturalist’ who ‘accepts as real only entities studied by the sciences’ (pp. 29, 241). In the end, while Rauscher’s Kant is perhaps tidied up sufficiently to appeal to contemporary naturalists and science fans, what remains is not only not the historical Kant but also someone who would have to disavow the main claims in Kant’s ethics.
1 God
There are a surprisingly large number of references to ‘God’ in the index to Naturalism and Realism in Kant’s Ethics, especially given the fact that its author is determined to read Kant as someone who accepts as real only entities studied by the sciences. But God, according to Rauscher’s Kant, can and should ‘be understood in a metaphysically naturalistic framework’. He thus rejects ‘any realism about God’ (p. 149). In other words, God does not exist. God is merely ‘a useful concept without an object’ (p. 174). God ‘is not seen as a substance; rather, God is an idea created by reason for moral purposes’ (p. 177). What moral purposes? God (that is to say, the concept of God – not a God who actually exists) is ‘needed for the realization of the highest good’ (p. 42).
But in what way is the concept of God needed for the realization of the highest good? As Kant sees it, realizing the highest good involves an impartial and fair distribution of happiness in accord with virtue on a universal scale – ‘the exact correspondence of happiness with morality’ (KpV, 5: 125). And this gargantuan distribution task – a task that must also be carried out ‘disinterestedly’ and ‘solely from impartial reason’ (5: 124) if it is to be done correctly – is far beyond the capacities of mere finite human beings, even if they do someday (do not hold your breath) manage to achieve ‘a
civil society
which can administer justice universally’ (IaG, 8: 22). Part of the reason for this is that ‘[t]he real morality of actions (their merit and guilt), even that of our own conduct, … remains entirely hidden from us’ (A551/B579n.; cf. GMS, 4: 407; MS, 6: 392; RGV, 6: 51). But God, who ‘knows the heart’ (RGV, 6: 67; cf. Luke 16:15), is not stymied by this inscrutability of motives conundrum. Also, given his omniscience and omnipotence (see KpV, 5: 140), God is capable of carrying out challenging tasks that mere mortals – even if their ‘cosmopolitical disposition’ does someday manage to win ‘the upper hand over the selfish predisposition of people’ (Anth, 7: 412; for discussion, see Louden Reference Louden2014) – are simply incapable of. So the realization of ‘the highest good is possible only with God’s help’ (Louden Reference Louden2015a: 123). Humans cannot do it on their own. Even though philosophy cannot prove that God exists, in order to realize the highest good ‘it is morally necessary to assume the existence of God’ (KpV, 5: 125).
But note that Kant says we must assume ‘the existence (das Dasein) of God’ (KpV, 5: 125; cf. 124, 132). No mere concept without an object could possibly carry out the universal distribution of happiness in accordance with individual virtue that is required to realize the highest good. For strictly speaking, a concept cannot do anything. And even if humans somehow get revved up after their practical reason constructs the concept of God (which seems to be Rauscher’s thought), they will still lack the necessary power and discernment to carry out the universal union of happiness and virtue.
Granted, Kant does occasionally describe God as if he were a mere concept rather than a being who exists. For instance, in the Opus Postumum, God is described as not being a substance ‘outside my thought’ (21: 21) – ‘not a substance to be found outside me but merely a moral relationship in me’ (21: 149; for discussion, see Förster Reference Förster2000: esp. 82, 173). And Rauscher does make heavy use of this material (see pp. 149, 174–7). But as others have pointed out, Kant’s remarks about God in the Opus Postumum ‘are often in open contradiction with each other’ (Ward Reference Ward1972: 161). For instance, elsewhere in the Opus Postumum God is described as ‘the highest cause of world beings and … a person’ (OP, 21: 19), and no mere concept can be either a cause of other beings or a person. And in yet another passage Kant even claims that ‘to have religion, the concept of God is not required (still less the postulate: “There is a God”)’ (21: 81). Because of the contradictory claims about God that we find in the Opus Postumum, I do not think it is a suitable text to turn to in seeking out Kant’s main claims about God.Footnote
3
2 Freedom
The question of free will – a ‘difficult problem on the solution of which millennia have worked in vain’ (KpV, 5: 96) – poses a particularly severe challenge for metaphysical naturalism. For what is traditionally meant by this idea is that humans have the capacity to act without being causally determined by factors beyond their control, and that it is in virtue of this capacity that they are responsible for their actions. If free will exists, how could it be an entity studied by any science that assumes that all events are causally determined? For those who believe in free will, it appears that ‘there can be no science of man’ (Chisholm Reference Chisholm2009: 181).
Although freedom for Kant is one of the three postulates of pure practical reason (see KpV, 5: 132), its status, as Rauscher notes, is different ‘than the other two postulates of immortality of the soul and the existence of God’ (p. 204). For the reality of freedom is proved by the moral law, and its reality in turn grounds the possibility of the other two postulates. As Kant notes in the Preface to the second Critique:
Now, the concept of freedom, insofar as its reality is proved by an apodictic law of practical reason, constitutes the keystone of the whole structure of a system of pure reason, even of speculative reason; and all other concepts (those of God and immortality), which as mere ideas remain without support in the latter, now attach themselves to this concept and with it and by means of it get stability and objective reality, that is, their possibility is proved by this: that freedom is real, for this idea reveals itself through the moral law. (KpV, 5: 3–4; cited by Rauscher on pp. 204–5)
Freedom is a condition of the moral law (morality and responsibility do not make sense without freedom), while God and immortality are ‘only conditions of the necessary object of a will determined by this law’ (KpV, 5: 4) – namely, they are necessary in order to realize the highest good.
But in part because Kantian freedom is a postulate of practical reason, Rauscher interprets it in the same way that he interprets God and immortality. Freedom along with God and immortality are merely ‘claims postulated for practical purposes as concepts which function to support moral life without ontological implications’ (p. 204). In plainer English, freedom is not real (see pp. 231, 47). When humans engage in deliberation, they ‘decide as if they are free’ (p. 106), but in deliberating in this manner they make no ‘claim to reality of any nonnatural cause’ (p. 204), and hence their conception of what they are doing ‘is compatible with a metaphysical naturalism’ (p. 204).
However, in settling for an essentially compatibilist and naturalist reading of Kantian freedom, Rauscher lays himself open to some of Kant’s most powerful rhetoric. This strategy is nothing but ‘a wretched subterfuge (ein elender Behelf)’ (KpV, 5: 96), and the result achieved is at bottom ‘nothing better than the freedom of a turnspit, which, when once it is wound up, also accomplishes its movements of itself’ (5: 97). Whether the cause of action lies ‘within the subject or outside him’ (5: 96) makes no difference when it comes to moral responsibility, for in either case we are talking about a causal chain in nature that controls the agent. And this is why Kant rejects compatibilism of either a Humean or Leibnizian variety, insisting rather on ‘transcendental freedom, which must be thought of as independence from everything empirical and so from nature as such (Unabhängigikeit von allem Empirischen und also von der Natur überhaupt)’ (KpV, 5: 96–7). Rauscher, in keeping within his self-imposed constraint of metaphysical naturalism, contends that ‘transcendentally free reason can exist in nature’ (pp. 120–1), but this seems to fly squarely in the face of one of Kant’s main claims in ethics.
3 Immortality
Finally, immortality – a topic much less on philosophy’s current agenda than freedom or even God. If Ray Kurzweil and his fellow Singularitarians are to be believed, ‘a form of immortality’ will be achievable by ‘the middle of the twenty-first century’ (Kurzweil Reference Kurzweil2006: 325), but Bernard Williams perhaps represents the views of more readers of this journal in his conviction that ‘it is a good thing … that we are not’ immortal and that we are ‘lucky in having the chance to die’ (Williams Reference Williams1973: 82, 100).
Although immortality is discussed far less by Rauscher than either God or freedom, his remarks on this topic bear scrutiny, and they do form an important part of the picture I am attempting to sketch. Immortality, as one of the three postulates of practical reason, makes ‘no ontological claims about actual objects’ (p. 83). That is, immortality, according to Rauscher’s Kant, is not real. Rather, it is a mere idea that functions as a heuristic aid in pursuing certain moral goals – namely, the idea of immortality ‘is needed for the realization of the highest good’ (p. 42). And a ‘metaphysical naturalism, of course, would preclude any role in morality for the immortality of the soul’ (p. 43).
But why on Kant’s view is immortality needed for the highest good? As he sees it, the complete conformity of the will with the moral law which is necessary for virtue to be rewarded with happiness ‘can only be found in endless progress toward that complete uniformity’ (KpV, 5: 122). But this necessary endless progress is itself ‘possible only on the presupposition of the existence (Existenz) and personality of the same rational being continuing endlessly (which is called the immortality of the soul)’ (KpV, 5: 122). It should be clear that Kant is making an ontological claim about an actual object here. The immortality of the soul must be real in order for his argument to make sense. If we substitute the thin gruel of a mere idea of immortality that does not refer to anything in the real world, then there is no endless progress, no personality that continues endlessly, and hence no highest good in Kant’s sense. So here too, it does seem that Rauscher’s interpretation is not consistent with one of the main claims in Kant’s ethics.
In closing, two more quick points: (1) In my own work I too have often argued that Kant is closer to naturalism than many of his friends as well as foes realize. Kant’s naturalism is perhaps most noticeable in his philosophy of education, where he criticizes existing educational theories on the ground that ‘everything in them works against nature’, and urges their replacement by a new educational method ‘which is wisely derived from nature herself (aus der Natur selbst gezogen) and not slavishly copied from old habit and inexperienced ages’ (AP, 2: 449). But this is a species of what I have called ‘weak naturalism’ (Louden Reference Louden2000: 8), and it is much more modest than the gung-ho metaphysical naturalism that Rauscher attributes to Kant. (2) As Rauscher notes, at bottom his reading of Kant is highly reminiscent of the famous ‘als ob’ interpretation developed by Hans Vaihinger over a century ago (see esp. pp. 150–1, n. 2). According to this interpretation, ‘human life is structured by a set of assumptions and ideas which are themselves “fictions” but which help humans beings survive and thrive’ (p. 150, n. 2). But just as many have questioned whether the sceptic can ‘live his skepticism’ by arguing that a life ‘without belief is not … a possible life for man’ (Burnyeat Reference Burnyeat1983: 141), I also wonder whether Vaihingerian fictionalism is liveable. Humans ‘must act and reason and believe’ (Hume Reference Hume1975: 160), and replacing beliefs with fictions (particularly fictions about fundamental matters such as God, freedom and immortality) may make action difficult. Also, at least for those of us who take Kant’s ethics seriously – particularly the importance he attaches to truthfulness – there is an additional moral problem. If ‘I ought not to lie, no matter how great the benefits to myself and my friend might be’ (MS, 6: 481, cf. 429; GMS, 4: 389; VRML, 8: 426–7), then is there not also something morally wrong in acting on what we know are false propositions, no matter how great the benefits to myself and my friend might be?
You have
Access
Metaphysics has as the proper end of its investigation only three ideas: God, freedom, and immortality … (B395n.)Footnote 1
Frederick Rauscher’s Naturalism and Realism in Kant’s Ethics Footnote 2 is a bold and well-written interpretation of Kant’s practical philosophy, one that exhibits a mastery not only of Kant’s own texts (his published works as well as his extensive lectures, notes and fragments), but also the flourishing secondary literature on Kant as well as relevant currents in contemporary philosophy – particularly as regards the central topics of naturalism and realism. But despite (and, I suspect, also to a certain extent because of) Rauscher’s intimate familiarity with Kant’s texts, there is a formidable methodological warning issued near the beginning of the book that makes critical discussion of its main theses difficult. For Rauscher is ‘not providing a strictly exegetical work’, and he acknowledges that there are ‘passages in Kant’s writings that are inconsistent with elements of … [his] interpretation’ (p. 5). Nor does he claim ‘to have presented precisely the historical Kant’s position’ (p. 242). Rather, Rauscher believes he has offered ‘an interpretation that encompasses the main claims in Kant’s ethics and shows how Kant either did or could have, using the resources available within his practical philosophy, presented an entirely metaphysically naturalistic ethics’ (p. 242). Fair enough. But is there sufficient consensus concerning what the ‘main claims in Kant’s ethics’ are and what these claims mean and imply for the tribunal of reason to conduct a fair trial and issue its judgement (see Axi–xii; for discussion, see O’Neill Reference O’Neill1989: 3–28)? I am honestly not sure. Additionally, there is the pragmatic constraint imposed by the editors of Kantian Review on each of the participants in this particular tribunal to adhere to their respective word limits. But if consensus regarding Kant’s main claims in ethics does not yet exist, is it likely to be attained in the space of a few pages?
In what follows I will concentrate on some of Kant’s main claims about God, freedom and immortality, key concepts which – according to both Kant and Rauscher – properly belong ‘not to physics, that is, to speculative reason, but to morals’ (KpV, 5: 140; cf. 138), but which – or so I shall argue – do not belong to morals in the thin way that Rauscher envisages. I am focusing on these three perennial topics in part because I believe they illustrate concretely what many readers will find most problematic about Rauscher’s book – namely, its defence of the claim that Kant can and should be read as a ‘metaphysical naturalist’ who ‘accepts as real only entities studied by the sciences’ (pp. 29, 241). In the end, while Rauscher’s Kant is perhaps tidied up sufficiently to appeal to contemporary naturalists and science fans, what remains is not only not the historical Kant but also someone who would have to disavow the main claims in Kant’s ethics.
1 God
There are a surprisingly large number of references to ‘God’ in the index to Naturalism and Realism in Kant’s Ethics, especially given the fact that its author is determined to read Kant as someone who accepts as real only entities studied by the sciences. But God, according to Rauscher’s Kant, can and should ‘be understood in a metaphysically naturalistic framework’. He thus rejects ‘any realism about God’ (p. 149). In other words, God does not exist. God is merely ‘a useful concept without an object’ (p. 174). God ‘is not seen as a substance; rather, God is an idea created by reason for moral purposes’ (p. 177). What moral purposes? God (that is to say, the concept of God – not a God who actually exists) is ‘needed for the realization of the highest good’ (p. 42).
But in what way is the concept of God needed for the realization of the highest good? As Kant sees it, realizing the highest good involves an impartial and fair distribution of happiness in accord with virtue on a universal scale – ‘the exact correspondence of happiness with morality’ (KpV, 5: 125). And this gargantuan distribution task – a task that must also be carried out ‘disinterestedly’ and ‘solely from impartial reason’ (5: 124) if it is to be done correctly – is far beyond the capacities of mere finite human beings, even if they do someday (do not hold your breath) manage to achieve ‘a civil society which can administer justice universally’ (IaG, 8: 22). Part of the reason for this is that ‘[t]he real morality of actions (their merit and guilt), even that of our own conduct, … remains entirely hidden from us’ (A551/B579n.; cf. GMS, 4: 407; MS, 6: 392; RGV, 6: 51). But God, who ‘knows the heart’ (RGV, 6: 67; cf. Luke 16:15), is not stymied by this inscrutability of motives conundrum. Also, given his omniscience and omnipotence (see KpV, 5: 140), God is capable of carrying out challenging tasks that mere mortals – even if their ‘cosmopolitical disposition’ does someday manage to win ‘the upper hand over the selfish predisposition of people’ (Anth, 7: 412; for discussion, see Louden Reference Louden2014) – are simply incapable of. So the realization of ‘the highest good is possible only with God’s help’ (Louden Reference Louden2015a: 123). Humans cannot do it on their own. Even though philosophy cannot prove that God exists, in order to realize the highest good ‘it is morally necessary to assume the existence of God’ (KpV, 5: 125).
But note that Kant says we must assume ‘the existence (das Dasein) of God’ (KpV, 5: 125; cf. 124, 132). No mere concept without an object could possibly carry out the universal distribution of happiness in accordance with individual virtue that is required to realize the highest good. For strictly speaking, a concept cannot do anything. And even if humans somehow get revved up after their practical reason constructs the concept of God (which seems to be Rauscher’s thought), they will still lack the necessary power and discernment to carry out the universal union of happiness and virtue.
Granted, Kant does occasionally describe God as if he were a mere concept rather than a being who exists. For instance, in the Opus Postumum, God is described as not being a substance ‘outside my thought’ (21: 21) – ‘not a substance to be found outside me but merely a moral relationship in me’ (21: 149; for discussion, see Förster Reference Förster2000: esp. 82, 173). And Rauscher does make heavy use of this material (see pp. 149, 174–7). But as others have pointed out, Kant’s remarks about God in the Opus Postumum ‘are often in open contradiction with each other’ (Ward Reference Ward1972: 161). For instance, elsewhere in the Opus Postumum God is described as ‘the highest cause of world beings and … a person’ (OP, 21: 19), and no mere concept can be either a cause of other beings or a person. And in yet another passage Kant even claims that ‘to have religion, the concept of God is not required (still less the postulate: “There is a God”)’ (21: 81). Because of the contradictory claims about God that we find in the Opus Postumum, I do not think it is a suitable text to turn to in seeking out Kant’s main claims about God.Footnote 3
2 Freedom
The question of free will – a ‘difficult problem on the solution of which millennia have worked in vain’ (KpV, 5: 96) – poses a particularly severe challenge for metaphysical naturalism. For what is traditionally meant by this idea is that humans have the capacity to act without being causally determined by factors beyond their control, and that it is in virtue of this capacity that they are responsible for their actions. If free will exists, how could it be an entity studied by any science that assumes that all events are causally determined? For those who believe in free will, it appears that ‘there can be no science of man’ (Chisholm Reference Chisholm2009: 181).
Although freedom for Kant is one of the three postulates of pure practical reason (see KpV, 5: 132), its status, as Rauscher notes, is different ‘than the other two postulates of immortality of the soul and the existence of God’ (p. 204). For the reality of freedom is proved by the moral law, and its reality in turn grounds the possibility of the other two postulates. As Kant notes in the Preface to the second Critique:
Now, the concept of freedom, insofar as its reality is proved by an apodictic law of practical reason, constitutes the keystone of the whole structure of a system of pure reason, even of speculative reason; and all other concepts (those of God and immortality), which as mere ideas remain without support in the latter, now attach themselves to this concept and with it and by means of it get stability and objective reality, that is, their possibility is proved by this: that freedom is real, for this idea reveals itself through the moral law. (KpV, 5: 3–4; cited by Rauscher on pp. 204–5)
Freedom is a condition of the moral law (morality and responsibility do not make sense without freedom), while God and immortality are ‘only conditions of the necessary object of a will determined by this law’ (KpV, 5: 4) – namely, they are necessary in order to realize the highest good.
But in part because Kantian freedom is a postulate of practical reason, Rauscher interprets it in the same way that he interprets God and immortality. Freedom along with God and immortality are merely ‘claims postulated for practical purposes as concepts which function to support moral life without ontological implications’ (p. 204). In plainer English, freedom is not real (see pp. 231, 47). When humans engage in deliberation, they ‘decide as if they are free’ (p. 106), but in deliberating in this manner they make no ‘claim to reality of any nonnatural cause’ (p. 204), and hence their conception of what they are doing ‘is compatible with a metaphysical naturalism’ (p. 204).
However, in settling for an essentially compatibilist and naturalist reading of Kantian freedom, Rauscher lays himself open to some of Kant’s most powerful rhetoric. This strategy is nothing but ‘a wretched subterfuge (ein elender Behelf)’ (KpV, 5: 96), and the result achieved is at bottom ‘nothing better than the freedom of a turnspit, which, when once it is wound up, also accomplishes its movements of itself’ (5: 97). Whether the cause of action lies ‘within the subject or outside him’ (5: 96) makes no difference when it comes to moral responsibility, for in either case we are talking about a causal chain in nature that controls the agent. And this is why Kant rejects compatibilism of either a Humean or Leibnizian variety, insisting rather on ‘transcendental freedom, which must be thought of as independence from everything empirical and so from nature as such (Unabhängigikeit von allem Empirischen und also von der Natur überhaupt)’ (KpV, 5: 96–7). Rauscher, in keeping within his self-imposed constraint of metaphysical naturalism, contends that ‘transcendentally free reason can exist in nature’ (pp. 120–1), but this seems to fly squarely in the face of one of Kant’s main claims in ethics.
3 Immortality
Finally, immortality – a topic much less on philosophy’s current agenda than freedom or even God. If Ray Kurzweil and his fellow Singularitarians are to be believed, ‘a form of immortality’ will be achievable by ‘the middle of the twenty-first century’ (Kurzweil Reference Kurzweil2006: 325), but Bernard Williams perhaps represents the views of more readers of this journal in his conviction that ‘it is a good thing … that we are not’ immortal and that we are ‘lucky in having the chance to die’ (Williams Reference Williams1973: 82, 100).
Although immortality is discussed far less by Rauscher than either God or freedom, his remarks on this topic bear scrutiny, and they do form an important part of the picture I am attempting to sketch. Immortality, as one of the three postulates of practical reason, makes ‘no ontological claims about actual objects’ (p. 83). That is, immortality, according to Rauscher’s Kant, is not real. Rather, it is a mere idea that functions as a heuristic aid in pursuing certain moral goals – namely, the idea of immortality ‘is needed for the realization of the highest good’ (p. 42). And a ‘metaphysical naturalism, of course, would preclude any role in morality for the immortality of the soul’ (p. 43).
But why on Kant’s view is immortality needed for the highest good? As he sees it, the complete conformity of the will with the moral law which is necessary for virtue to be rewarded with happiness ‘can only be found in endless progress toward that complete uniformity’ (KpV, 5: 122). But this necessary endless progress is itself ‘possible only on the presupposition of the existence (Existenz) and personality of the same rational being continuing endlessly (which is called the immortality of the soul)’ (KpV, 5: 122). It should be clear that Kant is making an ontological claim about an actual object here. The immortality of the soul must be real in order for his argument to make sense. If we substitute the thin gruel of a mere idea of immortality that does not refer to anything in the real world, then there is no endless progress, no personality that continues endlessly, and hence no highest good in Kant’s sense. So here too, it does seem that Rauscher’s interpretation is not consistent with one of the main claims in Kant’s ethics.
In closing, two more quick points: (1) In my own work I too have often argued that Kant is closer to naturalism than many of his friends as well as foes realize. Kant’s naturalism is perhaps most noticeable in his philosophy of education, where he criticizes existing educational theories on the ground that ‘everything in them works against nature’, and urges their replacement by a new educational method ‘which is wisely derived from nature herself (aus der Natur selbst gezogen) and not slavishly copied from old habit and inexperienced ages’ (AP, 2: 449). But this is a species of what I have called ‘weak naturalism’ (Louden Reference Louden2000: 8), and it is much more modest than the gung-ho metaphysical naturalism that Rauscher attributes to Kant. (2) As Rauscher notes, at bottom his reading of Kant is highly reminiscent of the famous ‘als ob’ interpretation developed by Hans Vaihinger over a century ago (see esp. pp. 150–1, n. 2). According to this interpretation, ‘human life is structured by a set of assumptions and ideas which are themselves “fictions” but which help humans beings survive and thrive’ (p. 150, n. 2). But just as many have questioned whether the sceptic can ‘live his skepticism’ by arguing that a life ‘without belief is not … a possible life for man’ (Burnyeat Reference Burnyeat1983: 141), I also wonder whether Vaihingerian fictionalism is liveable. Humans ‘must act and reason and believe’ (Hume Reference Hume1975: 160), and replacing beliefs with fictions (particularly fictions about fundamental matters such as God, freedom and immortality) may make action difficult. Also, at least for those of us who take Kant’s ethics seriously – particularly the importance he attaches to truthfulness – there is an additional moral problem. If ‘I ought not to lie, no matter how great the benefits to myself and my friend might be’ (MS, 6: 481, cf. 429; GMS, 4: 389; VRML, 8: 426–7), then is there not also something morally wrong in acting on what we know are false propositions, no matter how great the benefits to myself and my friend might be?