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How Common Is Common Human Reason? The Plurality of Moral Perspectives and Kant’s Ethics


In his practical philosophy, Kant aims to systematize and ground a conception of morality that every human being already in some form is supposedly committed to in virtue of her common human reason. While Kantians especially in the last few years have explicitly acknowledged the central role of common human reason for a correct understanding of Kant’s ethics, there has been very little detailed critical discussion of the very notion of a common human reason as Kant envisages it. Sticker critically discusses in what ways Kant is committed to the notion that there are certain rational insights and rational capacities that all humans share, and thus investigates critically how Kant thinks moral normativity appears to the common human being, the rational agent who did not enjoy special education or philosophical training.

I am grateful to the philosophy departments of the University of Bristol, the University of the West of England, to Waseda University, Kings College London and the London Post-Kantian Seminar for providing venues to present my material as well as to Jens Timmermann, Kiyoshi Chiba, Joe Saunders, James Camien McGuiggan, Joanna Burch-Brown, Seiriol Morgan, Charlotte Alderwick and Katrina Mitcheson for discussion and feedback. Work on this article was supported by a 2-year research fellowship from the Irish Research Council (GOIPD/2016/244). Moreover, this research was supported by the Ministry of Science and Higher Education of the Russian Federation grant no. 075-15-2019-1929, project “Kantian Rationality and Its Impact in Contemporary Science, Technology, and Social Institutions”, Immanuel Kant Baltic Federal University (IKBFU), Kaliningrad.

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  1. 1.

    See many works by Ameriks, such as Ameriks (2003); also Grenberg (2013), Zhouhuang (2016), as well as Geiger (2010) and Sticker (2014, 2015a, b, 2016a, b, 2017a and b).

  2. 2.

    We already find this foreshadowed in the First Critique (CpR A/B: 830–1/859–60) and, most prominently, expressed in the title of Groundwork I: “Transition from common to philosophical moral rational cognition” (GW 4:393).

  3. 3.

    Kant himself indicates that it was Rousseau who inspired his egalitarianism (Notes 20: 44). See Callanan 2019 for more on Kant’s reception of Rousseau.

  4. 4.

    Other passages that make this apparent are Kant’s discussions of how common agents would judge that it is inappropriate to do the externally right thing only as a means to something else, since there is nothing of higher authority than morality (GW 4:397, TP 8: 284, Tone 8: 403, Ped 9: 493–4).

  5. 5.

    I argue for this in detail in Sticker (2020 forthcoming).

  6. 6.

    I discuss the relationship between common cognition of duty and universality in greater detail in Sticker 2015a.

  7. 7.

    See also GW 4:403, 422, 423, CPracR 5: 27 for examples. Geiger 2010, 281 maintains that common agents are aware of “what moral laws bind them without employing the universalization test”. In Sticker 2015a, I argue that common agents do employ a common universalization test (albeit not a reflected philosophical formula).

  8. 8.

    CPracR 5: 44. See also GW 4:421–423, CPracR 5: 44, 69–70. Yet, another version of the common universalization test is taking “account (a priori) of everyone else’s way of representing in thought” by “holding one’s judgement up not so much to the actual as to the merely possible judgements of others, and putting oneself in the position of everyone else” (CPJ 5: 293.32–294. 3). Since this Maxim of Enlarged Thought is not explicitly introduced in a moral context, I will bracket it here. See Anth: 7: 200, 228–9, and Zhouhuang, sensus communis, 23–32, 44–6 for more.

  9. 9.

    See Piper (2012, 246) for a formulation of the universalization procedure along those intuitive lines. See Sensen (2014, 169) for an interpretation of the Categorical Imperative based on a “demand of fairness: One should not make an exception for oneself in the sense that one should not regard oneself as something better” (see also GW 4:424). According to Sensen (2014, 175), this notion of fairness is “more or less a human universal”.

  10. 10.

    I here cannot address well-known empty formalism and false positive/negative objections against universalizability as an ethical criterion. See instead Wood (1999, 102–6), Sensen (2014), Nyholm (2015), Bojanowski (2018) and Sticker (forthcoming) for discussion. We should bear in mind that the claim that certain moral insights and criteria of moral evaluation are universally shared among rational human beings is different from and independent of the notion that universality or universalizability can function as such a criterion of evaluation. I am only concerned with the former claim.

  11. 11.

    For sceptical takes see Kerstein (2002) and Formosa (2017), ch. 1. For a defence of a strong version of this equivalence, see Mariña’s contribution to this volume.

  12. 12.

    The modern locus classicus for this observation is J.L. Mackie (1977, 37) who bases his argument from relativity on the “actual variations in the moral codes”. These variations are supposedly better explained by how moral norms reflect different ways of life than by an underlying objective framework of moral values.

  13. 13.

    Even philosophers who do stress the importance of common human reason for Kant avoid discussion of this problem. There is no discussion in Zhouhuang’s monograph on the topic (Zhouhuang 2016) and no extended discussion that I am aware of in the works of Ameriks. Likewise, Grenberg (2013) does not discuss the problem, presumably because she believes that the element of the common perspective she focuses on, the experience of unconditional obligation, is sufficiently uncontentious to be widely shared. It is also striking that there is now a fair amount of literature on Kant’s discussion of ethnic and other diversity, but not of different fundamental moral principles and values prevailing in different cultures. See, for instance, Larrimore (2008) who shows that Kant was very concerned with human variety and diversity, but who only discusses this diversity in terms of races, temperaments and national character. Kleingeld (2014, 46) notes that “Kant’s characterizations of the different ‘races’” extendto “politically relevant mental and agential characteristics”. She does not indicate, however, whether it also extends to different notions of the good and duty.

  14. 14.

    In V-prac Herder 27: 43, the Innuits’ parricide is mentioned as seeming support for Voltaire’s claim that conscience is not innate but acquired (and hence sensitive to cultural standards).

  15. 15.

    See, however, Sticker 2017b who argues that Kant, in fact, also does call for some revisions of the common cognition of duty and proposes that these revisions be made popular by educators and popular philosophers. These revisions are, however, still part of Kant’s larger project of systematizing and vindicating the most essential insights of common agents.

  16. 16.

    GW 4:422; see also ibid. 454, Cprac R 5: 61, 98.

  17. 17.

    See Refl 15: 877 f., Menschenkunde 25: 1187, 28: 290. Ludwig 2014 emphasizes that at least since the Religion Kant explicitly acknowledges that there can be agents endowed with empirical practical rationality only and not under the moral law (see esp. Rel 5:26).

  18. 18.

    There is now a lively scholarly debate about Kant’s racism. Bernasconi (2001) argues that Kant was an influential theorist of the notion of different human races. Kleingeld (2007) partly defends Kant by arguing that he renounced his earlier views on race in the 1790s. Larrimore (2008) argues that Kant did not even change his racist views in the light of his developed conception of moral equality and autonomy. Most recently, Allais (2016) has proposed that Kant’s views on race are instructive objects of study for a deeper understanding of the structures of racism. See also her contribution to this volume, where she argues that Kant’s conception of self-deception can help us understand racist structures we are unable to change as individuals.

  19. 19.

    Saunders (2018, 5) points out that it is, in fact, a challenge for Kant to accommodate childhood, dementia, mental illnesses and other conditions that impact rational capacities. For Kant, rationality and freedom are not in time, whereas childhood, dementia and mental illnesses are occurrences in time.

  20. 20.

    See Sticker (2015b) for more on this most basic form of moral education as well as Moran (2012, 162–3) who stresses that education, which fosters the development of moral agency, is so basic that almost all human beings undergo it.

  21. 21.

    I should note that if we accept that (some) Nazis are savages devoid of common human reason, then this implies that agents can lose common human reason. After all, Nazi war criminals, the architects of the Holocaust and the like did not grow up in a society that was completely controlled by Nazi ideology, as this ideology was the state-imposed doctrine only from 1933 to 1945.

  22. 22.

    Even otherwise staunch defenders of Kant admit that some of Kant’s normative claims are “ill-advised” and cannot be “sustained in the light of his own theory” (Timmermann 2005, 244).

  23. 23.

    See Kant’s provisional distinction in the Groundwork (GW 4:421.fn.), and the definite one in his Metaphysics of Morals (MM 6:390).

  24. 24.

    There is debate in the literature about whether latitude also extends to the question of how much obligatory ends are to be furthered. See van Ackeren and Sticker (2018) for discussion and a proposal.

  25. 25.

    See MM 6:375 fn., 390, 392, 393 for the distinction between (a) and (b) on the one hand and (c) on the other hand.

  26. 26.

    I here assume that the Formula of Universal Law is the basic formula of the CI, but a similar distinction could be made based on other formulae.

  27. 27.

    See Illingworth et al. (2011, 3–7) for a long list of applied questions pertaining to charitable giving that philosophers nowadays consider philosophically relevant.

  28. 28.

    Cf. Mariña’s discussion of suicide in her contribution to this volume.

  29. 29.

    David James (1999, 48–52), for instance, argues that some of the casuistic examples concerning self-killing are not cases of self-murder and hence permissible.

  30. 30.

    To be clear, I am not claiming that Kant himself was aware of the distinction between self-murder and other forms of suicide, but merely that he has the resources to draw this distinction. I should also note that, of course, Kant could also drop suicide as an example for perfect duties to self, as I contemplated above. My point here is one about the application of perfect duties in general and the example of suicide is intended as an illustration.

  31. 31.

    “It suffices that they are there, that they surround him, and that they are human beings, and they will mutually corrupt each other’s moral disposition” (Rel 6:94).

  32. 32.

    See also Rel 6:168–70, MM 6:430, Theo 8:265–6, 200.

  33. 33.

    It is of course an oversimplification to speak of “Innuits” as one homogeneous group. It is now well established that there was and is great diversity between different groups of Innuits, as well as that senicide was relatively rare and that some groups were strongly opposed to it.

  34. 34.

    It seems that what is doing the work here is not age per se but independence or the ability to provide for oneself. Kant might be to some extent sympathetic to the children’s and parents’ plight, because he himself places great emphasis on independence, for instance as a necessary condition for full citizenship (MM 6:313 ff.). I am grateful to Ansgar Lyssy for this point and to Kate Moran for discussion of the role of personal independence in Kant.

  35. 35.

    This, of course, greatly depends on how we formulate the maxim. For instance, if we think that the maxim is something like “Killing people” we would think that a universalization procedure should rule it out.


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Sticker, M. (2021). How Common Is Common Human Reason? The Plurality of Moral Perspectives and Kant’s Ethics. In: Lyssy, A., Yeomans, C. (eds) Kant on Morality, Humanity, and Legality. Palgrave Macmillan, Cham.

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