On What Matters
Parfit's 2011-17 three-volume late masterpiece — a synthesis of Kantian, contractualist, and consequentialist ethics on the "triple theory," and an extensive defense of non-naturalistic moral realism
Tradition: Twenty-first-century analytic ethics / moral realism
Kantian ethics, contractualism, and rule-consequentialism climb the same mountain from different sides — and what we ought to do is independently real
On What Matters is Parfit's second major book, twenty-seven years after Reasons and Persons. Volumes I and II appeared in 2011 (1,400 pages); Volume III in 2017, posthumously, a few months after Parfit's death. The work has two central ambitions. First, the "Triple Theory": the three great traditions of modern moral philosophy — Kantian deontology (in T. M. Scanlon's contractualist reformulation), rule-consequentialism (in Brad Hooker's form), and a revised Kantianism on what universal-acceptance maximization requires — converge on the same first-order conclusions when properly formulated; "they are climbing the same mountain from different sides." Second, the metaethics: against the wave of expressivist, constructivist, and naturalistic-reductive accounts that dominated late-twentieth-century metaethics, Parfit defends a non-naturalistic but non-metaphysically-extravagant moral realism — moral facts are normative, irreducible to natural facts, but do not require an additional metaphysical commitment beyond their irreducibility. Volume III responds at length to the major critics of Volumes I and II (Susan Wolf, Allen Wood, Barbara Herman, Frances Kamm, Peter Railton). The work is the longest and most ambitious work of analytic moral philosophy in the twenty-first century.
Author
Editions cited
- On What Matters, Vol. I (Oxford UP, 2011); Vol. II (Oxford UP, 2011); Vol. III (Oxford UP, 2017, published shortly after Parfit's death January 1, 2017)
School Embodiments
The work is paradigm twenty-first-century analytic philosophy — meticulous argument, exhaustive consideration of objections, careful taxonomic distinctions between candidate views.
"Non-Religious Ethics is at an early stage. We cannot yet know whether, as Sidgwick failed to do, we shall be able to defend it on a level with the great religious moralities." (On What Matters, Vol. II, ch. 36)
Parfit's positive ethical view is heavily Kantian — the universal law formulation, properly reformulated, is one of the three peaks of the triple-theory mountain.
"An act is wrong just when such acts are disallowed by some principle that is optimific, uniquely universally willable, and not reasonably rejectable. This is the Triple Theory." (On What Matters, Vol. I, ch. 17)
The defense of non-naturalistic moral realism is one of the book's two central ambitions — against expressivism (Blackburn, Gibbard), constructivism (Korsgaard), and reductive naturalism (Railton), Parfit defends an irreducible normative reality.
"There are some claims about reasons and what we ought to do that are not just true but irreducibly true — true in a way that does not require us to revise our ordinary understanding of what we are talking about." (On What Matters, Vol. II, ch. 32)
Parfit's confidence that rational reflection can deliver substantive moral conclusions — that the three great traditions can be shown to converge by careful argument — is rationalist in the classical sense.
"If we cannot reach agreement at the level of moral first principles, we may yet reach it at the level of which acts are right or wrong." (On What Matters, Vol. I, Preface)
Although Parfit defends non-naturalistic realism, he insists his position involves no extravagant metaphysics — moral facts are not in addition to natural facts in any way that requires explanation beyond their normativity.
"Non-Reductive Cognitivism is not committed to a Platonic realm of moral entities. It is committed only to the irreducibility of normative truths." (On What Matters, Vol. II, ch. 30)
The Triple Theory's strategy — show that great traditions converge on first-order conclusions even where they diverge in foundational vocabulary — has a pragmatist tolerance for vocabulary differences.
"What matters is not which moral principle has the best foundational story, but which principle gives the best account of which acts are right or wrong." (On What Matters, Vol. I, ch. 16)
Volume II's long discussion of religious ethics treats divine-command and natural-law positions with full seriousness, even as Parfit himself was a secular philosopher.
"The great religions have been the principal carriers of moral seriousness for much of human history. Non-religious ethics must learn from them, not merely against them." (On What Matters, Vol. II, ch. 36)
Internal Tensions
The Triple Theory's convergence claim is contested at every level: Wood and Herman argue the Kantian peak Parfit reaches is not Kant's; Hooker accepts the rule-consequentialist peak; Scanlon partially accepts the contractualist peak but resists the convergence. The metaethical defense of non-naturalistic realism has won fewer adherents than Parfit hoped (Schroeder, Street, Enoch all wrote against it). Volume III's extensive replies remain incomplete on some issues — Parfit died before completing his planned response to climate-justice critics. The work's influence is more diffuse than Reasons and Persons but its place in twenty-first-century ethics is established.
I. Time
The temporal sweep — twenty-seven years between Reasons and Persons and On What Matters, three decades of revision behind the published trilogy.
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II. Space
The space of analytic ethics — Oxford, Harvard, the Philosophy and Public Affairs community whose objections shape Volume III.
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III. Matter
The biological-historical human agent whose moral life is the topic; Parfit's austere physicalism about the agent is inherited from Reasons and Persons.
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IV. Observer
The morally serious agent whose reasoning Parfit's philosophy aims to support; the philosopher who attends to where the great traditions actually meet.
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V. Energy
The energies of careful argument — the book's thousands of pages of close engagement with objections.
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VI. Information
Normative truths as irreducible information — facts about what we ought to do that are not reducible to facts about what we want or what causes us to do things.
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Personas with the nearest attribute fingerprint
Historical figures whose own classification on the same six-dimensional grid lands closest to this work's. Computed by attribute-agreement on coordinates both address.
Computed school proximity
The work's attribute fingerprint scored against all schools using the same quiz scorer. Useful as a sanity check on the hand-curated embodiments above.
How On What Matters resolves each dilemma
48 resolved positions across 4 dimensions, including 3 distinctive where the majority of schools go the other way · 9 unaligned.
Each dimension is sorted so minority positions come first. Mainstream positions are folded into an expandable list.
Time · 9 dilemmas · 3 distinctive
Persistence, the future, and the direction of becoming.