[sosull]

Immanuel Kant came up with the idea of a categorical imperative. It’s one of the foundation stones in the field of moral philosophy (or ethics). An example would be the moral requirement not to kill other people. The only way to successfully prove that there are no moral requirements is by arguing the point with people who don’t know any better.

[skissane]

There are many philosophers who disagree with Kant's categorical imperative though – even among those who agree that ethics is objective (in some sense). The categorical imperative gives morality a deontological flavour, to which many will object–such as consequentialists. And there are others who don't object to the deontological flavour per se, but who think there are better foundations for such a morality (e.g. natural law theorists).

I agree with your position that ethics is objective, but I don't think Kant's categorical imperative is a very good argument for its objectivity – a person can coherently accept ethics/morality as being objective, yet doubt or deny the categorical imperative. I think "ethics is objective" is one of those things where very many people can agree on a conclusion, yet disagree massively on what is the correct reasoning to reach that conclusion.

[sosull]

It was a somewhat rushed point, admittedly. I was reaching for enlightenment-era imagery to challenge the seeming disavowal of morality itself. I note that OP extended those remarks elsewhere to claim that the law is the preferred source of moral constraint. I'm not even sure of what to say to that.

But I very much appreciate the depth of your point. I've always found validation (?) in the deontological aspect of Kant's idealism because I think it neatly describes why people feel obligations to those they interact with most closely (i.e. I feed my child because I should, rather than to avoid his hunger). I certainly take your point that the categorical imperative isn't the best or only tool for interpreting moral dilemmas. Honestly, I was bringing it up in part because it's a recognisable phrase that might infer that there's more to the question of ethics than unexamined instinct.