More precisely, can someone provide a relatively intuitive explanation or justification for why failing the categorical imperative test should be indicative of an action which is morally wrong?

I'm only referring to the first two formulations of the categorical imperative, that is, "Act only according to the maxim which you can will that it should become a universal law without contradiction", and "Always treat humanity as an end, never merely as a means".

I understand how it rules out actions as morally wrong, but I don't understand how to articulate why an action not conforming to these two formulations of the categorical imperative is morally wrong.

Thank you.

  • one might think that's too broad. for some, it may suffice to say we need a rational maxim, and those are the closest fit. this is not an answer!
    – user29495
    Nov 29, 2017 at 10:09
  • 1
    possible duplicate of this
    – user29495
    Nov 29, 2017 at 10:10
  • 2
    Possible duplicate of: philosophy.stackexchange.com/questions/39638/… . The answer does answer this question as well imho.
    – Philip Klöcking
    Nov 29, 2017 at 13:42
  • To expand on my comment above: Since all actions can, because of how the very concept of morality is thought, only be moral if the will is governed by the categorical imperative, it follows that if the will is not governed by the categorical imperative, the action is immoral: A(m)→W(ci), therefore not(W(ci)) → not(A(m)) (A=action, m=moral, W=will, ci=governed by categorical imperative)
    – Philip Klöcking
    Nov 29, 2017 at 18:12
  • @PhilipKlöcking i sense the idea that the CI is the only means to think about absolute duties. do you suppose this? why?
    – user29495
    Nov 30, 2017 at 4:46

2 Answers 2


One way to interpret the Categorical Imperative is "Don't be a hypocrite in any thing you do. Not even to the smallest degree." Failing to meet this criterion means there are things you consider proper that you would not consider proper if the positions were permuted. In other words, you are a hypocrite who wishes to hold other individuals to higher standards than yourself.

Humans generally have a strong innate sense of fairness, which is directly offended by hypocrisy. Unless badly treated for an extended period, people expect a minimum degree of fairness. So one half of the argument for it is naturalistic: It amplifies a basic belief that all of us naturally cling to from childhood.

The other half is somewhat bizarrely abstract. It proceeds from his notion of categories that that there has to be one and only one such rule that is internally consistent and applies to all cases. A lot of folks do not accept that premise, because they think the notion of categories and intelligence that Kant starts from are extreme and somewhat arbitrary. But Kant accepts his own definitions as obvious.

He then proves this rule is internally consistent by using it on a number of cases without getting any contradictions, and he decides that it applies to all cases because it applies to itself: It is itself a maxim that humans, by that naturalistic observation, can will to be universally true. Meanwhile, the available alternatives do not apply to themselves without generating contradictions, loops or regresses of one sort or another. Then since he has accepted that any such rule must be the only such rule, it is perfect.

  • What's wrong with being a hypocrit? (I try not to be one in real life; just trying to understand Kant) What's wrong with permuting me and others? There's an essential difference between us - I always perceive through my senses and never through others'. I don't feel their pleasure or pain (except through empathy, but that's much weaker). I don't die when they do. Perhaps Kant (like me) was unable to reason any further, so he resorted to postulating an "imperative" to justify everything else he considers good?
    – ngn
    Jan 29, 2018 at 22:45
  • @ngn. Then what is wrong with simply being immoral? Who says morality should exist? Kant isn't saying you have to have a morality, just that this is the one most natural to humans. People have a built-in dislike of inconsistency, often even when it favors them. We have an internal sense of logic and an expectation that the world will be minimally consistent. You can beat that out of someone, but every three-year-old knows when you are being unfair to them, and is suspicious when the world changes too quickly, even in their favor. We can tell from the time they spend staring at anomalies.
    – user9166
    Jan 30, 2018 at 2:38
  • Thanks, I should ruminate over the argument from inconsistency avoidance. Then what is wrong with simply being immoral? - The fear that others will try to punish me. Who says morality should exist? - that's what I'm trying to find out. Or rather, why should it? Kant aside, my best take is: it's a self-regulating mechanism that emerges in large groups of individuals. Moral norms enhance their well-being as a group.
    – ngn
    Jan 30, 2018 at 2:57
  • @ngn Ultimately, I agree with you. I buy the argument that concern for others is a virtue signal for confidence you can accumulate adequate resources to defend yourself from the outside world. Originating as concern for infants, the broader it expands, the greater ability to sustain the waste of not being totally selfish it demonstrates -- that indicates intelligence among your relatives. And we breed for intelligence, as a basic survival virtue. But that has nothing to do with Kant...
    – user9166
    Jan 30, 2018 at 19:18
  • At the opposite end from Kant, Nietzsche makes a very good argument that even if 'cultivation of our herd' is absolutely inborn, and is really best for the species at the cost of various individuals, it is still a bad thing, and should not be the basis of morality. If we slowly converge on something that is meant to demonstrate intelligence, at the cost of actually using intelligence to its greatest advantage, we are, as a species, buying a bill of goods.
    – user9166
    Jan 30, 2018 at 19:28

Kant's primary emphasis in his ethical writings - certainly the Groundwork and the Critique of Practical Reason - is on our rational nature. Just as theoretical reason works on unconditional, universalisable rules (such as modus ponens in logic), so practical reason should display an analogue. It too should operate under unconditional, universalisable rules. Two examples of these are the two formulations you quote of the CI.

Practical reason in the sense that is central to Kant's ethical theory is not instrumental, means/ end rationality - the calculation of efficient means to clearly conceived ends. Kantian practical reason is about consistency. 'Act only in accordance with that maxim which you can at the same time will that it become a universal law' (Groundwork, 421 : M. Gregor tr.). One way of putting it is to say that the CI embodies rationality in the sense of mutual consistency : we can all act on the CI without mutual self-defeatingness or conflict. (Just as we can all use modus ponens in theoretical reason without its causing conflicting views.)

Kant's view is that there is a co-incidence between the consistent conduct (personal and interpersonal) that the CI requires and the conduct required by morality - at least by ordinary moral thinking. This is a major part of the point of his four moral examples in the Groundwork. What the CI rules out or requires, so too does ordinary moral thinking as embodied in the four examples.

He does not, so far as I can see, explain the nature of this co-incidence. He presumably doesn't see it as purely chance, a mere contingency, but he also doesn't show how the requirements of the CI and of ordinary moral thinking necessarily co-incide. He assumes that they do.

There are reasons to doubt that they actually do so. It is not at all clear that if the CI does rule out suicide (G 421-2), for example, ordinary moral thinking agrees in condemning suicide in Kant's unconditional terms.

There is a further point. In Kant's view the summum bonum, supreme good, for humanity is the combination of virtue and happiness. But there is no rational connection, certainly no entailment, between acting on the CI and achieving happiness in the present life. Indeed, happiness may be defeated through the fact that the CI can and often does require us to act contrary to self-interest. Since it is rational to desire at our supreme good, the summum bonum, acting morally can be irrrational because it requires us to act against our own happiness insofar as it bids us act contrary to self-interest. Kant recognises that the pursuit of self-interest has a kind of rationality even though it falls low in the scales vis-a-vis the consistency embodied in the CI. Also happiness includes self-interest (which is not the same as selfishness) and is recognised as a part of the summum bonum.

Kant's response to this problem, namely that acting morally, acting on the CI, does not guarantee happiness, so that the summum bonum is not necessarily within our grasp in the present life - indeed, seldom is so - by arguing for the rationality of faith in God, the afterlife and the immortal soul. In the afterlife, happiness and morality coalesce. God puts together what an imperfect world has separated.

The trouble is that in the Critical Philosophy the existence of God, the afterlife and the immortal soul are all unprovable. What Kant calls rational faith, some others would regard as wishful thinking. There are Kantian atheists and Kant cannot demonstrate that his post-mortem reconciliation of happiness and morality is anything more than a desideratum (a 'nice if') rather than a fact.

Hope this helps. I'll try to clarify if anything looks obscure or false to what Kant says.

  • Two points: One, as far as I understand, the link between morality and CI in the Groundwork comes down to Kant's understanding of what constitutes a moral judgement in ordinary thinking: That a moral act it is judged right or good not by virtue of being good for something else, but absolutely and in itself. Two, a main point of the second critique is that because happiness and morality may divert in life, an immortal soul and God have to be thought as necessary in order to make happiness for morality and moral perfection (i.e. the supreme good) possible (in the afterlife).
    – Philip Klöcking
    Dec 30, 2017 at 17:03
  • @Philip Klöcking. Thanks for this. It valuably adds to what I said but doesn't so far as I can see contradict it. I deliberately didn't include the afterlife because I wanted to keep the answer short and as far as possible within the concepts the Questioner used but of course you are right that Kant does invoke the afterlife as the scene where reason, virtue, and happiness combine.
    – Geoffrey Thomas
    Dec 30, 2017 at 18:47
  • No major protest here, it was intended as a clarification. I think my main problem is with your use of rationality. You seem to suggest that rationality is to be reduced to instrumentality, i.e. the rational thing to do is that which is in your (self-)interest. That seems problematic for me, especially in the context of Kant, as it may render any distinction between acting out of inclination and acting out of rationality meaningless. Points in the direction of Randian Objectivism (or Nietzschean master morality), which is basically the opposite of Kant.
    – Philip Klöcking
    Dec 30, 2017 at 19:07
  • @Philip Klöcking. If I may add another point. God and the afterlife solve Kant's problem about the summum bonum and the divergence of virtue from happiness in the present life. But it is not actually necessary to think of an immortal soul and God in the way in which it is necessary to think of (say) phenomena under the categories. God and the immortal soul are as you known indemonstrable within the Critical Philosophy. One can accept the Critical Philosophy but reject God and the immortal soul as not at all (as Kant does) matters of rational faith. There are atheist Kantians.
    – Geoffrey Thomas
    Dec 30, 2017 at 19:09
  • @Philip Klöcking. That's fine, thanks. I don't reduce reason to instrumental rationality. Be reassured ! I stressed practical reason as operating under unconditional, universalisable rules, which have nothing necessarily to do with means/ end rationality. Glad to have cleared this up. I didn't realise I had been misunderstood. It was my fault. One can't be too careful in expounding Kant and you have helped me. Best : GT
    – Geoffrey Thomas
    Dec 30, 2017 at 19:14

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