It's impossible to dispute first principles in ethics.
It's impossible to dispute first principles in ethics.
It's impossible to dispute first principles in ethics.
First principles, even though they can't be proven, can be attacked on grounds of consistency. Suppose that I accept a moral principle -- but you point out a very implausible consequence that follows from it. Do I accept this consequence? If not, then I'm inconsistent -- and I have to rethink my position.