Agreement between moral theories › Three approaches, stated carefully

Consequentialism explains moral assessment through consequences. For the convergence argument, the consequentialist component is a form of rule consequentialism. It evaluates principles through the consequences associated with their general or universal adoption, under the formulation being considered. Acts are then assessed through those principles. This differs from evaluating each individual act solely by whether that act produces the best available outcome.

The distinction matters for promises. Suppose that breaking a promise on one occasion would produce a small benefit. An act-based calculation and an assessment of a generally accepted principle concerning promise breaking ask different questions. The principle may affect assurance and reliance across many situations. A rule consequentialist must specify which consequences of accepting or following a principle count, rather than merely insert the act's immediate benefit into a larger-sounding description.

Kantian reasoning asks about principles that could serve as universal laws, and about the reasons everyone has for willing them. Parfit critically revises formulations associated with Kant. A reader should therefore distinguish what Kant originally wrote from the proposals Parfit thinks most defensible. His argument is a philosophical reconstruction, not a claim that every familiar interpretation of Kant already entails the Triple Theory.

Scanlonian contractualism evaluates principles through reasonable rejection. It concerns justification to individuals who seek terms of conduct others could also reasonably accept. Actual agreement is insufficient: someone may accept a bad arrangement because they lack power, information or confidence. The question concerns the quality of reasons for rejecting principles, not simply the number of people who object.

These approaches also place their tests at different points. An assessment of outcomes asks how things go. A test of rational willing asks what people have reason to choose as a universal law. Reasonable rejection asks what burdens or other objections individuals can press against a principle. Showing that these tests support the same principles requires a connecting argument. Renaming all three as concern for people would leave that work undone.