The following thought experiment can be taken in a number of ways. For some, it will be a fun little logic game. For others, it will be yet further proof that philosophers are annoying people who ought to be avoided at parties. And for others still, it illustrates a broad class of scenarios in which we might actually find ourselves. So, without further delay…
Suppose we live in a world in which the following things are clearly true:
- There are exactly two viable moral theories: duty-based ethics and consequence-based ethics. (It’s not at all important what these theories say, only that they are clearly incompatible with each other.)
- Whichever moral theory we believe in also dictates what we ought to believe.
- Duty-based ethics clearly dictates that we ought to believe in consequence-based ethics.
- Consequence-based ethics clearly dictates that we ought to believe in duty-based ethics.
In such a world, what ought we to believe and how do we go about justifying our beliefs to others?