QuestionsWhat makes something right?The categorical imperative: the false promise
What makes something right?Duty

The categorical imperative: the false promise

Immanuel Kant 1724 · 1804Set the limits of reason; act from duty.
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What it claims

Making a false promise is not permitted.

Why

If everyone made false promises, nobody would believe any promise: the rule would defeat itself.

In short

"The categorical imperative: the false promise" is an argument by Immanuel Kant (Groundwork, 4:421-422) on the question "What makes something right?" (answer: duty). Its claim: Making a false promise is not permitted. According to AskPhilosophy's logic check (Z3 solver), the conclusion does follow from its 3 premises. AskPhilosophy presents 3 objections, 0 of them with a documented reply, and the original text behind each premise, checked word for word.

Groundwork, 4:421-422
Valid

Kant seeks a moral test that depends neither on desires nor on consequences. He applies it to an example: promising to repay a loan while knowing one will not.

P1An action is permitted only if one can will its maxim (its rule) to become a universal law.
P2The maxim here is: "when I need money, I borrow and promise to repay, knowing I never will".
P3Universalised, this maxim contradicts itself: if everyone made false promises, no one would believe promises any more, and promising would become impossible.
Therefore making a false promise is not permitted.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
The argument is valid: P1 and P3 are essential. Criticism targets P1 (is this the right test?) and how the maxim is formulated: a more specific maxim might pass the test.
Analogy. A false promise is like a free rider: it only works because others play by the rules. If everyone did the same, the system it exploits would vanish.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Benjamin Constant 1797 · attacks premise 1

If a murderer asks where your friend is hiding, the rule "never lie" would oblige you to give him away. A principle that leads there cannot be absolute.

no reply
summary: their text is not yet in our corpus
Kant did reply, but that text is not yet in our corpus.
Hegel 1802 · attacks premise 1

The test is empty: mere absence of contradiction does not say what to do. Any content can be made consistent if phrased the right way.

no reply
summary: their text is not yet in our corpus
We have not yet found a direct reply by Kant in the texts.
John Stuart Mill 1861 · attacks premise 3

When Kant shows why a maxim cannot be universalised, he is really describing its bad consequences: his test hides a calculation of consequences.

no reply
summary: their text is not yet in our corpus
No reply possible: objection raised in 1861, after the author's death (1804).
What today's voices say
Defend it
Bishop Robert BarronHe finds Kant's duty ethics noble but 'abstract and inhuman', blind to circumstances and consequences.