Begging The Question
How Parfit's magnum opus assumed what he hoped to prove
Derek Parfit’s monumental On What Matters is, at first glance, the magnum opus of a philosopher determined to reconcile and defend the most sophisticated moral theories of our time. But the more closely you read, the more clearly you see that Parfit was working backwards from a conclusion he already held: moral realism must be true, and our best moral theories must converge on it.
1. The Pre-committed Metaethics
From the outset, Parfit takes for granted that irreducible normative truths exist — timeless, mind-independent facts about what we have reason to do. He does not present this as a hypothesis to be tested. It is treated as a datum, a fixed point around which the rest of his argument revolves. Error theory, non-cognitivism, and other forms of moral anti-realism are dismissed not because they fail under their own logic, but because they would make morality "less important than it really is." In other words, the motivational consequences of denying realism are taken as indirect evidence against it.
This is a classic sign of working backwards: the undesirability of a worldview is treated as evidence of its falsity.
2. Triple Theory by Design
Parfit’s signature move is the Triple Theory, a synthesis of Kantian contractualism, rule consequentialism, and Scanlonian contractualism. He selects these three precisely because they already agree in most real-world cases. The differences are then massaged and reframed until they appear as surface variations on a single underlying truth. This convergence is presented as confirmation of moral realism.
But in fact, the direction of reasoning is reversed. He needs convergence to bolster realism, so he chooses theories that already converge. The synthesis is not a discovery of deep unity; it is a construct engineered to protect a prior commitment.
From a subjectivist perspective, convergence is unsurprising: humans share evolved psychological heuristics, cultural constraints, and agency-preserving norms. These yield overlapping prescriptions without requiring mind-independent moral facts.
3. Counterexample Containment
When a case arises where the Triple Theory's components would yield conflicting prescriptions — coercive-sacrifice dilemmas, lifeboat scenarios, extreme distributive justice cases — Parfit narrows the scope of "reasonable rejection" or redefines what counts as "making things go best" until the prescriptions align again.
This is not the behaviour of someone willing to let his core thesis take damage. It is the behaviour of someone determined to shield the convergence claim from disconfirmation.
4. The Conditionalist Rebuttal
Our own framework rejects moral realism on Conditionalist grounds: all truth claims require interpretation, and interpretation depends on background value-conditions. There is no such thing as an unconditional moral truth; every "ought" is of the form:
If X values Y, then Z is preferable.
Moral disagreement between fully informed, rational agents is not necessarily an error; it can simply reflect different value-conditions. Normativity emerges from agents' chosen values, their understanding of the world, and their position in the Quantum Branching Universe (Vantage, Measure, Credence).
From this perspective, the Triple Theory's convergence reflects shared human conditions — evolutionary, cultural, and cognitive — not timeless moral facts.
5. Objectivity as a Starting Point
Parfit's objectivity is a starting assumption, not an end point. His arguments for realism function as confirmations of a standing belief, never as neutral investigations. The entire project is framed to arrive where it began.
In our framework, any claim of objectivity must survive the Conditionalist filter: can it be stated without smuggling in hidden background conditions? Moral realism consistently fails that test.
6. Motivation and Truth
Parfit repeatedly suggests that rejecting realism would make morality less motivating, and treats this as a pragmatic reason to accept it. But usefulness is not truth. A belief can motivate while being false; conversely, a true belief can fail to inspire. Conflating motivational utility with ontological status is another sign of conclusion-driven reasoning.
Conclusion
On What Matters is a brilliant work of philosophical engineering, but it is not an open-ended search for moral truth. It is a defence brief for moral realism, constructed by selectively choosing, reshaping, and unifying theories until they fit the predetermined verdict.
From our vantage, this is precisely why it fails. Moral realism is not the natural conclusion of converging theories; it is the starting point Parfit could not abandon. A truly robust moral framework must survive the falsity of realism. Ours does, because it grounds normativity in explicit, conditional value-commitments and embeds it in a physically coherent ontology. Parfit's does not.