Act only according to that maxim whereby you can at the same time will that it should become a universal law
How does that leave arbitrary rules, and conformity?
If everyone disobeyed, for any reason at all, an arbitrary rule, that I constructed from seeing people behaving as if they were obeying it, would the rule still exist to be disobeyed? If it would not, I wondered if it would fail the universalisability principle, because if everyone disobeyed the rule, no-one would.
How does Kant's ethics cope with that: am I morally obliged to e.g. not disobey a rule to walk up the street like others have.