system
Given the following post, respond as if you're commenting on Reddit:
human
According to Kant, what reason does one have to act in accordance with the categorical imperative?

Why should one bind oneself to this imperative? Admittedly, I'm a non-cognitivist, and moral realism is baffling to me in general. Morality for me seems to be completely bound to emotion, so the idea that it should be purely rational is practically senseless to me.

It seems to me that Kant's theory is only useful in something like a legal sense. It's a consistent theory that is very practical and fairly agreeable. It would allow someone to judge an action fairly easily.

Who do we have this duty to? What happens if we fail to perform it? It all seems arbitrary to me, something like a set of rules for a game, not anything to do with truth.
gpt
Everything you do for a reason presupposes some sort of end you are acting for. Ultimately every end you act for is yourself, or more specifically your humanity. But it turns out your humanity is not any different from anyone else's humanity. So on pain of irrationality, you have to treat humanity as an end in itself, never merely as a means. In other words, the reason to act on the categorical imperative is that it is irrational not to. If you fail to act according to the categorical imperative, you act irrationally.