Source: Prof Michael Sandel, Justice: ..., Episode 06: "MIND YOUR MOTIVE"

Question: Despite Prof Sandel's answer below, I still don't understand why JSM was wrong.
Does Kant mean: you can appeal only to consequentialism while test[ing] an action?
But if you use consequentialism as a test, then you're still appealing to consequentialism?

Motivation behind question:

John Stuart Mill [JSM] made this criticism of Kant: If I universalize the maxim and find that the whole practice of promise-keeping would be destroyed if universalized, I must be appealing somehow to consequences. If that's the reason not to tell a false promise[what?]. So JSM agreed with that criticism against Kant, but JSM was wrong.

Kant is often read as appealing to consequences: The world would be worse of if everybody lied. Because then nobody could rely on anybody else's word. Therefore you shouldn't lie.

That's not what Kant is saying exactly, although it's easy to interpret him as saying that. I think what he's saying, is that this is the test. This is the test of whether the maxim corresponds with the categorical imperative. It isn't exactly the reason. It's not the reason. The reason you should universalize to test your maxim, is to see whether you are privileging your particular needs and desires over everybody else's. It's a way of pointing to this feature. This demand of the categorical imperative, that the reasons for your actions shouldn't depend, or their justification, on your interests, your needs, your special circumstances being more important than somebody else's. That I think is the moral intuition lying behind the universalization test.

  • I made it so one could read it as if reading a quote without all the timestamps, and simplified a sentence of two in to help clarity. I'm fine with opening this question, but could you just lastly clarify "if that's the reason not to tell a false promise." I don't understand what that sentence means.
    – stoicfury
    Apr 4, 2015 at 6:44
  • @stoicfury Thank you. Please allow me a few days to relisten to Prof Sandel, because he (and not I) said that. I'll write back.
    – user8572
    Apr 4, 2015 at 18:17

3 Answers 3


Simply put, the problem is that the word consequences has at least two distinct usages. One usage is actual consequences -- meaning what happens after you did something. The other usage is logical consequences -- which refer to those things logically follow from an action.

Both forms of consequences bear a necessity relation to their antecedents, but the former states facts -- the window broke when he hit a baseball into it whereas the latter states things hypothetically. In other words, if you were to scream at the one year old, it would start crying.

The point Sandel is trying to make here is that Kant's test if we can say it looks at consequences only looks at these sort of logical consequences and then only as unrealized contingencies. Mill's objection to Kant confuses the two senses of consequences, because Kant's test finishes dealing with the hypothetical ones and is not concerned with the real ones.

In fact, this is an essential part of Kant's moral philosophy. In other words, on the Kantian picture, it is completely possible for you to act morally but for the effect in the real world to be something terrible. E.g., when you tell the truth to someone who uses that to cause harm. In the Kantian picture (at least as Kant presents it), you have a responsibility to truth-telling, but your responsibility ends in terms of what other agents might do with the truth. In other words, the concern is not for actual consequences.

At the same time, we can test our actions to see whether it would be logically incoherent to have a world that is built on everyone pursuing the same maxim of action (roughly meaning the same basis for action). For example, if I decide it is okay to cut in line whenever it is inconvenient to wait, then it's difficult to universalize this, because it would obliterate the sense of lines in the first place.


This is a good question! I think it is a common mistake to think that Kant is appealing to a "bad consequence" here. Universalizing the maxim "Brake a promise when it is convenient" leads to a contradiction, not a catastrophe. That is what tells us it is irrational (which is to say immoral) to break a promise. Another way of saying this is that treating the maxim as a moral law is strictly impossible. The mark of a moral maxim is that it can be universalized at all, not that it can be universalized without terrible consequences.

To put the consequence of universalizing the maxim as the destruction of the practice of promise-keeping is misleading. The contradiction is that there is no sense in which I am actually making a promise if I intend to break it when I find it difficult to keep it. There is no such thing as making a promise you don't intend to keep. That's why "Brake a promise when it is convenient" is incoherent: If the law holds, there can be no such thing as a promise, yet the law assumes that there is.

See Kant's Groundwork of the Metaphysics of Morals (especially pp. 402–403 in the Academy Edition).

  • While I broadly agree with the content of the answer, I beg to cite either after Academy Edition (GMM is Volume 4, pp. 387-463) or with a specification of the edition used. There are dozens out there, so "pp. 17-20" isn't exactly helpful. That being said, a minor nitpick: As Kant describes it, the more appropriate description would be contradiction in will here, see Kleingeld (2017).
    – Philip Klöcking
    May 19, 2019 at 9:56
  • @PhilipKlöcking Thanks! I fixed the problem with the citation. About the nitpick: I take it that the formulation "treating the maxim as a moral law is strictly impossible" is okay though? If so, my solution is to hope that people read it as making more precise what is meant by "universalizing the maxim leads to a contradiction". May 19, 2019 at 16:37

On what is perhaps a bit of a tangent, Kant does appeal to consequences in one way at least, in my view. The ultimate telos of his moral system is a world that is wholly governed by reason, i.e. a world onto which the categorical imperative has been imposed, or a world where the laws of human morality have become as immutable as the laws of nature.

  • Can you spell out more how this is an appeal to consequences?
    – virmaior
    Dec 16, 2016 at 13:17
  • It is perhaps an appeal to a consequence. I do not have the Groundwork at hand at the moment, but there seems to me to be a strong sense that at least part of why we should all do our duty is to bring about such a world. Dec 16, 2016 at 14:23
  • but bring about such a world refers to the logical consequences of the universalization of the a world with maxims like that rather than to the actual consequences of a particular person following that maxim.
    – virmaior
    Dec 16, 2016 at 15:23

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