How would Kant decide whether a law is ethical?

Question

From what I understand, I know that Kant believes that the purpose of government is to "[hinder] a hindrance to freedom" that people could impose on others. Additionally, in a Kantian government should guarantee:

• The freedom of every member of the state as a human being.
• The equality of each with every other as a subject.
• The independence of every member of a commonwealth as a citizen.

Additionally, Kant's categorical imperative assesses whether or not a decision is ethical or moral by asking the question of whether or not the decision would lead to a contradiction if it is universalized, however a law is already universalized, so applying the categorical imperative does not seem to make sense.

Finally, according to Kant, every citizen in a state should, theoretically consent to the law, even if not in practice. Is that, in essence one of the only requirements? How would one go about figuring out whether or not every single citizen would consent to the law?

Answer 1

To answer your question in the headline, ignoring the text body: The Perpetual Peace introduces what Kant calls a "touchstone" for laws. The government or the monarch is to ask, whether the people, not as individuals but as rational beings (just as virmaior explained), could or would agree to the law. Because this is so, there is no need to ask them.

I'm not sure it's right to ask how to ascertain whether a law is ethical, because the connection of right and morals is not as obvious as one might think. I don't need the categorical imperative to find out whether my actions are rightful, because to be rightful my actions don't need to be grounded in respect or understanding of moral necessity or anything, they just have to be compatible with everybody's freedom. That is why right [Recht] can't make people act morally right, for then its laws would have to act upon their motives, and that's impossible. All positive laws can do is to give people an incentive not to constrain other's legal freedom.

It's also not shown yet that positive laws have to be ethical, for it is possible that they rule in a "space" of morally irrelevant actions. Plus, there is readings of Kant that suggest that there is a good reason why the Rechtslehre (Doctrine of Right) comes prior to the ethical part of the Metaphysics of Morals, and that we cannot understand what it is for a law to be ethical before understanding what makes a law lawful.

I can't give you any references more specific than the Perpetual Peace as a whole, which isn't very long anyway, and the introduction plus first paragraphs of the Metaphysics of Morals

Answer 2

There's a lot of different things going on in your question(s).

I'll start with the last one:

according to Kant, every citizen in a state should, theoretically consent to the law, even if not in practice.

While there's a type of consent at work here, there's something more important involved in Kant's understanding of citizenship in this moral kingdom (or realm if you prefer). Viz., each citizen is rational and therefore arrives at the conclusions of reason as to what sort of laws would be harmonious for the kingdom to work. Thus, it becomes a kingdom of ends.

In other words, it's not that there is ever a moment that asks for our consent based on personal preference, taste, or advantage. Rather, the consent is that as rational beings we consent to rational laws.

This is there in abbreviated form in the Groundwork but an extended treatment of the relationship of the members of this community is handled in Religion within the Bounds of Reason Alone

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Your other question seems to focus on how Kant handles laws. Fortunately for us, Kant wrote a book about that called Rechtlehre translated either as Doctrine of Right or Metaphysical Principles of Right. This constitutes the first half of Kant's Metaphysics of Morals (not to be confused with the Groundwork of the Metaphysics of Morals).

In that text, the basic flow of how laws and rights work is that they proscribe those actions Kant believes are necessarily immoral. In other words, Kant thinks that we can as a society proscribe lying, murder, cheating, adultery (and any sex outside of a heterosexual marriage for that matter), and many other things. For each of these, Kant's arguments (which range a bit in quality) relate back to the idea that such actions are not capable of having a moral motivation, i.e., they could not be universalized OR they are not compatible with acknowledging rational persons (which Kant calls "humanity") as ends.

Thus, the test of any law is not whether it is law but whether it is a law that requires us to make exceptions for ourselves or others. OR for Kant, what is synonymous, whether it treats humanity in ourselves or other persons (even non-human rational persons) as mere means to our ends rather than as rational ends in themselves.

So Kant most definitely believes a law can be unjust. Specifically, any law that say would make it so that one person can use another (slavery) or any law that enables people to cheat others or that enables lying to prevail or dismantles private property.

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Thus returning to your bullet points, the "equality" in the Kantian system is always founded on the fact that each of us is a rational being. In this respect, it differs from a social contract theory that is compatible with the three bullet points you identify.

Again, the same qualifier must be added to "freedom." Kant believes we are empirically determined creatures but simultaneously that we possess rational freedom to determine our actions (per the third antinomy in the Critique of Pure Reason and elsewhere).

"Independence" too must be understood not as freedom to do whatever but as the ability to do what reason demands regardless of the actions of others or our passions.

I'm not sure if the above addresses what you intended to ask or not, but I'm having a little trouble finding the question.

Answer 3

Kant is quite explicit regarding how to decide whether law in the sense of a rule of right is moral or not in one of his later texts:

In order to make practical philosophy consistent with itself, it is neces- sary first to decide the question, whether in problems of practical reason one must begin from its material principle, the end (as object of choice), or from its formal principle, that is, the principle (resting only on freedom in external relations) in accordance with which it is said: So act that you can will that your maxim should become a universal law (whatever the end may be). The latter principle must undoubtedly take precedence; for, as a principle of right, it has unconditional necessity,... (Towards Perceptual Peace, 8:376-7, emphasis mine)

As the "formal principle" undoubtly is one form of the Categorical Imperative, each law that is not in accordance with it, is immoral (and indeed - as not in accordance with it's own formal principle - not a legitimate law at all).

Regarding the connection between freedom and the Categorical Imperative more generally, see this question, regarding how to universalise a maxim according to Kant and what this actually is, see this one.