Sign In

Remember Me

Immanuel Kant: Morality Necessitates Immortality

Immanuel Kant (1724-1804) was an 18th century philosopher, one of the earliest philosophers belonging to the enlightenment tradition, and often considered the father of German Idealism. Kant is remembered today more for his moral philosophy than his contributions to metaphysics and epistemology (Rohlf 2010). His contributions to the field of life-extension, however, remain almost completely unexplored, despite the fact that certain claims made in his Theory of Ethics arguably qualify him as a historical antecedent of the contemporary social movement and academic discipline of life-extension.

Marquis du Condorcet (1743-1794), another historical antecedent the modern longevity movement, appears to have originated the “idea of progress” in the context of the enlightenment, which became an ideological cornerstone of the enlightenment tradition. In Sketch for a Historical Picture of the Progress of the Human Mind, Condorcet not only conceives of the idea of progress in perhaps the first form it would take within the enlightenment tradition, but also explicates its link to indefinite life-extension, which was not an existing movement or academic discipline at the time of his writing:

Would it be absurd now to suppose that the improvement of the human race should be regarded as capable of unlimited progress? That a time will come when death would result only from extraordinary accidents or the more and more gradual wearing out of vitality, and that, finally, the duration of the average interval between birth and wearing out has itself no specific limit whatsoever? No doubt man will not become immortal, but cannot the span constantly increase between the moment he begins to live and the time when naturally, without illness or accident, he finds life a burden? (Condorcet 1795)

It is this very notion of infinite progress towards endlessly-perfectible states, carried forward after Condorcet by Kant and other members of the enlightenment tradition, that also underlies Kant’s own ties to the contemporary field of life-extension. Kant’s claim, made in his Theory of Ethics, that to retain morality we must have comprehensively unending lives – that is, we must never, ever die – I will argue qualifies him as a historical antecedent of the contemporary life-extension movement. In his Theory of Ethics (Kant 1996) under “Part III: The Summum Bonnum, God and Immortality” (Kant 1996, p. 350), Kant argues that his theory of ethics necessitates the immortality of the soul in order to remain valid according to the axioms it adheres to. This is nothing less than a legitimation of the desirability of personal immortality by one of the fathers of the Enlightenment tradition.

It is important to note that the aspects making it so crucial a concern to Kant’s ethical system have to do with indefinite lifespan in general, and indeed would have been satisfied using non-metaphysical (i.e. physical and technological) means of indefinite life extension – having more to do with the end of continued life, and indefinite-longevity in particular, than with the particular means used to get there, which in Kant’s case is a metaphysical means.

Karl Ameriks, writing in reference to Kant’s views on immortality, states that “… the question of immortality is to be understood as being about a continued temporal existence of the mind. The question is not whether we belong to the realm beyond time but whether we will persist through all time…Kant also requires this state to involve personal identity.” (Ameriks, 2000).

In the fourth section, “the immortality of the soul as a postulate of pure practical reason”, of the third part of “Theory of Ethics”, Kant writes: “Pure practical reason postulates the immortality of the soul, for reason in the pure and practical sense aims at the perfect good (summum bonnum), and this perfect good is only possible on the supposition of the soul’s immortality.” (Kant 1957, p. 350)

Kant is claiming here that reason (in both senses with which they are taken into account in his system – that is, as pure reason and practical reason) is aimed at perfection, which he defines as continual progress towards the perfect good (rather than, say, the attainment of any such state of perfection) and that as finite beings we can only achieve such perfect good through an unending striving toward it.

In a later section, “The Antinomy of Practical Reason (and its Critical Solution)” (Kant 1957, p. 358), he describes the Summum Bonnum as “the supreme end of a will morally determined”. In an earlier section, The Concept of the Summum Bonnum, Kant distinguishes between two possible meanings for Summum; (1) supreme in the sense of absolute (not contingent on anything outside itself), and(2)  perfect (not being part to a larger whole). We can conclude from the conjunction of these sections that Kant meant the Summum Bonnum to embody both meanings of “supreme”.

Kant then goes on to claim that personal immortality is a necessary condition for the possibility of the perfect good. In the same section he describes the Summum Bonnum as the combination of two distinct features: happiness and virtue (defining virtue as worthiness of being happy, and in this section synonymizing it with morality). Both happiness and virtue are analytic in Kant’s epistemological framework, and thus derivable from empirical observation.

However, their combination in the Summum Bonnum does not follow from either on its own and so must be synthetic, or reliant upon a-priori cognitive principals. Kant thusly reasons that the possibility of the Summum Bonnum requires God and the immortality of the soul because this is where Kant grounds his a-priori, synthetic, noumenal world – i.e. the domain where those a-priori principals exist (in/as the mind of God, for Kant).

Kant continues:

“It is the moral law which determines the will, and in this will the perfect harmony of the mind with the moral law is the supreme condition of the summum bonnum… the perfect accordance of the will with the moral law is holiness, a perfection of which no rational being of the sensible world is capable at any moment of his existence. Since, nevertheless, it is required as practically necessary, it can only be found in a progress in infinitum towards that perfect accordance, and on the principles of pure practical reason is nonetheless necessary to assume such a practical progress as the real object of our will.” (Kant 1957, p. 358)

Thus not only does Kant argue for the necessitated personal immortality of the soul by virtue of the fact that perfection is unattainable while constrained by time, he argues along an alternate line of reasoning that such perfection is nonetheless necessary for our morality, happiness and virtue, and that we must thus therefor progress infinitely toward it without ever definitively reaching it if the Summum Bonum is to remain valid according to its own defining-attributes and categorical-qualifiers as-such.

“Now, this endless progress is only possible on the supposition of an endless duration of existence and personality of the same rational being (which is called the immorality of the soul). The summum bonnum, then, practically is only possible on the supposition of the immortality of the soul; consequently this immortality, being inseparably connected with the moral law, is a postulate of pure practical reason (by which I mean a theoretical proposition, not demonstrable as such, but which is an inseparable result of an unconditional a priori practical law). This principal of the moral destination of our nature, namely, that it is only in an endless progress that we can attain perfect accordance with the moral law… For a rational but finite being, the only thing possible is an endless progress from the lower to higher degrees of moral perfection. In Infinite Being, to whom the condition of time is nothing… is to be found in a single intellectual intuition of the whole existence of rational beings. All that can be expected of the creature in respect of the hope of this participation would be the consciousness of his tried character, by which, from the progress he has hitherto made from the worse to the morally better, and the immutability of purpose which has thus become known to him, he may hope for a further unbroken continuance of the same, however long his existence may last, even beyond this life, and thus may hope, not indeed here, nor in any imaginable point of his future existence, but only in the endlessness of his duration (which God alone can survey) to be perfectly adequate to his will.” (Kant 1957, p. 359)

Thus, Kant first argues that the existence of the Summum Bonnum requires the immorality of the soul both (1) because finite beings conditioned by time by definition cannot achieve the absolute perfection of the Summum Bonnum, and can only embody it through perpetual progress towards it, and (2) because the components of the Summum Bonnum (both of which must be co-present for it to qualify as such) are unifiable only synthetically through a priori cognitive principals, which he has argued elsewhere must exist in a domain unconditioned by time (which is synonymous with his conception of the noumenal realm) and which must thus be perpetual for such an metaphysical realm to be considered unconditioned by time and thus noumenal.

Once arguing that the possibility of the Summum Bonnum requires personal immortality, he argues that our freedom/autonomy, which he locates as the will (and further locates the will as being determined by the moral law), also necessitates the Summum Bonnum.

In the first section, “The Concept of Summum Bonnum”, Kant writes that “it is a priori (morally) necessary to produce the summum bonnum by freedom of will…” He sees morality as a-priori and synthetic, and the determining principal which allows us to cause in the world without being caused by it – i.e. for Kant our freedom (the quality of not being externally-determined) requires the noumenal realm because otherwise we are trapped in the freedom-determinism paradox.

Thus the Summum Bonnum also vicariously necessitates the existence of God, because this is necessary for the existence of a noumenal realm unaffected by physical causation (note that Kant refers to physicality, or non-noumenal realm, as “the“phenomenal realm” and “the sensible world”). Such a God could be synonymous with the entire noumenal realm, with every mind forming but an atom as it were in the larger metaorganismal mind of a sort of meta-pantheistic, quasi-Spinozian conception of God – in other words one quite dissimilar to the anthropomorphic connotations usually invoked by the word.

Others have drawn similar conclusions regarding the claim that Kant’s immortality need not be metaphysical, and that physical, technological means of indefinite lifespans would satisfy Kant’s prerequisites for “indefinite progress towards the Summum Bonum” just as well as a metaphysically-bound soul would. Karl Ameriks summarizes Kant’s thoughts on immortality thusly:

“All other discussion of immortality in the critical period are dominated by the moral argument that Kant sets out in the second critique. The argument is that morality obligates us to seek holiness (perfect virtue), which therefore must be possible, and can only be so if God grants us an endless afterlife in which we can continually progress… As a finite creature man in incapable of ever achieving holiness, but on – and only in – an endless time could we supposedly approximate to it (in the eyes of God) as fully as could be expected… Kant is saying not that real holiness is ever a human objective, but rather that complete striving for it can be, and this could constitute for man a state of ‘perfect virtue’…” (Ameriks 2000)

The emphasis on indefinity is also present in the secondary literature; Ameriks remarks that Kant “…makes clear that the ‘continual progress’ he speaks of can ultimately have a ‘non-temporal’ nature in that it is neither momentary nor of definitive duration nor actually endless”. Only through never quite reaching our perfected state can we retain the perfection and infinite perfectibility inherent in imperfection.

Paul Guyer corroborates the claim that the real determining factor regarding Kant’s thoughts on the relationship between immortality and morality is not Kant’s claim that mind is a metaphysical entity or substance, but rather his claim that if morality requires infinite good and if we are finite beings then we must be finite beings along an infinite stretch of time in order to satisfy the categorical requirements of possessing such an infinity. Guyer writes that “..the possibility of the perfection of our virtuous disposition requires our actual immortality…” (Guyer 2000) and that “…God and immortality are conditions specifically of the possibility of the ultimate object of virtue, the highest good – immortality is the condition for the perfection of virtue and God that for the realization of happiness” (Guyer 2000).

In summary, it does not matter that Kant’s platform was metaphysical rather than technological, because the salient point is not the specific operation or underlying principles of the means used to achieve immortality, but rather the very end of indefinite longevity itself. Being able to both live and progress in(de)finitely constitute the loophole that provides, for Kant, both our freedom and our morality. Kant said we can’t die if we want to be moral, that we can’t die if we want to gain virtue and that we can’t die if we want to remain free. This I believe qualifies Kant as a veritable historical antecedent of the modern movement and academic discipline of life-extension.


[1].          Rohlf, M. (2010). “Immanuel Kant”, The Stanford Encyclopedia of Philosophy. Edward N. Zalta (ed.), URL:

[2].          Condorcet, M. J. A. N. C. (1795). Sketch for a historical picture of the progress of the human mind: tenth epoch. Dædalus: Journal of the American Academy of Arts & Sciences, 133(3), 65-82.

[3].          Kant, I. (1957). In T. M. Greene Kant selections. New York: Charles Scribner’s Sons.

[4].          Ibid,. p. 350.

[5].          Ameriks, K. (2000). Kant’s Theory of Mind: An Analysis of the Paralogisms of Pure Reason. Oxford University Press.

[6].          Kant, I. (1957). In T. M. Greene Kant selections, p. 350. New York: Charles Scribner’s

[7].          Ibid,. p. 358.

[8].          Ibid,. p. 359.

[9].          Ameriks, K. (2000). Kant’s Theory of Mind: An Analysis of the Paralogisms of Pure Reason. Oxford University Press.

[10].       Freydberg, B. (2005). Imagination of Kant’s critique of practical reason. Indiana University Press.

[11].       Guyer, P. (2000). Kant on Freedom, Law, and Happiness. Cambridge University Press


  1. ‘Kant then goes on to claim that personal immortality is a necessary condition for the possibility of the perfect good.’

    And the statement that this post makes towards the end, ‘This I believe qualifies Kant as a veritable historical antecedent of the modern movement and academic discipline of life-extension.’ do not really tie together.

    Kant suggested that immortality is a necessary condition for the perfectly good or moral being; however he does not goes on to say that, that is the reason we should march forward towards the path of immortality. I think, the main reason for not doing so, is that he knew that if the perfect good will come up through immortality, then the perfect bad will also come up. Like ying and yang perfect good won’t exist without the perfect bad (or at least it’s notion) in existence.

    So the question, we have infront of us is, Do we need the perfect good or do we want to prevent the perfect bad from arising?

  2. Hi,
    I will comment where this appears in linkdin.

Leave a Reply