Which Kantian principle is central to his ethical system?

• A. Act only on that maxim through which you can will that it should become a universal law
• B. The greatest happiness for the greatest number
• C. Do unto others as you would have them do unto you
• D. Follow social contract to ensure mutual advantage

Answer: (A)

Kant’s ethical framework centers on duty and the idea that moral rules must be applicable to everyone in the same way. The key test is the universalizability of your maxim: would you be willing to see the rule behind your action become a universal law? If you can honestly will that, the action is morally acceptable; if not, it isn’t. This captures why the specific Kantian principle is central: act only on maxims you could will to be universal laws.

So the best choice states this idea directly. It embodies Kant’s emphasis on the form of the rule behind an action, not its consequences. The other options reflect different moral theories: the greatest happiness for the greatest number points to utilitarianism, which weighs outcomes; do unto others as you would have them do unto you is the Golden Rule, a reciprocity-based guideline; and following a social contract aligns with contractarian theories. None of these, however, capture Kant’s universalizable-duty approach.