I'm having trouble understanding just how specific the circumstances can be when using the categorical imperative. My general understanding is that the categorical imperative urges you to consider whether you want to live in a world where everybody applies a rule that allows or disallows an action. Lying and littering make sense as things that we cannot allow everybody to do. Nevertheless, is this an absolute rule, or are there qualifying circumstances like "Don't lie unless by not lying you unnecessarily hurt someone's feelings" or "Don't litter unless a strong wind causes you to drop some plastic"? Does the categorical imperative allow for something like the subjective test: would a "reasonable person" act this way?

Recently I paid for a meal costing $18. When I handed a $20 note, I received $12 change by mistake. I handed the $10 back, but it made me think of the ethical implications here. If this only happens very rarely, then surely a world whereby everybody does not give back the extra change would still be a world we would want to live in. How specific can Kant's imperative get? For instance "Never wilfully underpay for a service" makes sense, we want to live in a world where prices have meaning, and if everybody tries to underpay then there is no point in having a price. But what about "Never wilfully accept extra change after paying"? To me, there doesn't seem to be a duty to hand back the change under the categorical imperative. I just did it because it seemed like the right thing to do (as per the 'golden rule').

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    Can you explain how this question is not answered here?
    – Philip Klöcking
    Commented Apr 30, 2017 at 8:03

1 Answer 1


I think Philip's answer elsewhere does address this issue and quite well.

To complement that here if you're finding it inadequate. There's three things to consider:

(1) Kant does not provide a very clear explanation of all the rules about what can and cannot be a maxim. Put another way, Kant just starts talking about maxims in Groundwork and there isn't much prior to that which operates from this framework. He doesn't give us rules for them even though universalizing them is central to morality.

(2) There's some recent literature (though going back to at least Allen Wood's earlier work) that suggests that (a) you're not allowed to maxim shop and (b) your maxim should reflect your subjective reason for acting.

(3) Kant's later works, especially Metaphysics of Morals: Doctrine of Virtue demonstrate some flexibility towards social niceties and mistakes that might apply here (for instance, you don't have to tell someone that they are ugly). (Here, the main thing is the quodlibetal questions where we seek Kant fielding harder things like -- is sacrificing yourself in battle suicide? or what makes lying wrong (again)?). This almost directly addresses your lying example.

A further consideration is that dealing with a shopkeeper is one of the examples in Groundwork (though there is disagreement whether Kant refers to three or four different accounts of doing so). Another point is that Kant claims that the different formulas are the same CI such that whatever maxim we come up with it should be identical with treating people as ends not means and identical with citizenship in the kingdom of ends.

All of that to say, I think Kant could come up with something that covers most cases along the lines of:

Always attempt to deal honestly in transacting with others.

Because the negation of this or the loss of this seems to be problematic to universalize (assuming we ignore Hegel's critique that whether or not we have a system of transactions and property is a priori arbitrary).

It does not guarantee success but Kant's morality is never about the guarantee of success. It's about the purity of the act of willing such that its accords with pure reason.

Suggested References

  • Immanuel Kant, Metaphysical Principles of Virtue in Practical Philosophy ed. Allen Wood
  • Thomas Hill, Blackwell Guide to Kant's Ethics (see this page)
  • Allen Wood, Kant's Ethical Theory
  • Marcia Baron, Kantian Ethics Almost without Apology

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