Derek Parfit
Derek Parfit was a British philosopher whose work on personal identity, ethics, and the foundations of morality is widely regarded as among the most important in twentieth-century analytic philosophy. His *Reasons and Persons* transformed debates about personal identity, future generations, and the structure of moral reasoning, while *On What Matters* attempted a grand synthesis showing that the three great moral traditions — Kantianism, consequentialism, and contractualism — converge on the same fundamental principles.
Key Ideas
Key Contributions
- ● Argued that personal identity is not what matters — what matters is psychological continuity and connectedness
- ● Identified the Repugnant Conclusion in population ethics, sparking an entire subfield of philosophical research
- ● Formulated the Non-Identity Problem concerning our obligations to future generations
- ● Attempted to show that Kantianism, consequentialism, and contractualism converge on the same fundamental moral principles
- ● Demonstrated that self-interest theory can be collectively self-defeating
- ● Transformed debates about personal identity through thought experiments involving teleportation, brain splitting, and gradual replacement
Core Questions
Key Claims
- ✓ Personal identity is not what matters in survival — what matters is psychological continuity and connectedness (Relation R)
- ✓ The self is not a separately existing entity; the reductionist view of personal identity is correct
- ✓ The Repugnant Conclusion — that a vast population of barely-worth-living lives is 'better' than a smaller, thriving one — shows deep problems in population ethics
- ✓ The Non-Identity Problem reveals that our choices about the future cannot wrong specific future people, since different choices produce different people
- ✓ Kantianism, consequentialism, and contractualism, properly formulated, are climbing the same mountain on different sides
- ✓ Self-interest theory is directly collectively self-defeating and should be rejected
Biography
Early Life and Education
Derek Antony Parfit was born on December 11, 1942, in Chengdu, China, where his parents were teaching preventive medicine. The family returned to England when he was one year old. Parfit was educated at Eton College and Balliol College, Oxford, where he studied modern history before turning to philosophy.
He spent his entire career at All Souls College, Oxford, as a Prize Fellow and later Senior Research Fellow, with regular visiting positions at Harvard, NYU, and Rutgers. He was famously reclusive and devoted to his work, reportedly working on philosophy for most of his waking hours.
Reasons and Persons (1984)
Reasons and Persons (1984) is one of the most influential works of analytic philosophy published in the twentieth century. It addressed four clusters of problems:
Part One argued against self-interest theory (the view that each person has most reason to do what is best for herself), showing that it can be directly collectively self-defeating — everyone acting in their self-interest can make everyone worse off.
Part Two exposed a series of paradoxes in consequentialist reasoning, including the repugnant conclusion in population ethics: for any population of ten billion people with a very high quality of life, there is a much larger population whose members have lives barely worth living that is, by total utilitarian standards, better.
Part Three presented Parfit's revolutionary account of personal identity. Drawing on thought experiments about teleportation, brain splitting, and gradual replacement, Parfit argued that personal identity is not what matters. What matters is psychological continuity and connectedness — the holding of memory, intention, and character links — not the existence of some further fact of identity. "I" am not a separately existing entity over and above my brain, body, and experiences. This "reductionist" view of personal identity has profound ethical implications: if identity is not what matters, then the separateness of persons that grounds much of deontological ethics is less deep than commonly assumed.
Part Four addressed our obligations to future generations, revealing deep puzzles about how present choices affect which future people will exist (the Non-Identity Problem).
On What Matters (2011/2017)
Parfit's later masterwork, On What Matters (published in two volumes in 2011, with a third in 2017), attempted to show that the three great traditions of moral philosophy — Kantianism (the morality of duty and respect for persons), consequentialism (the morality of good outcomes), and Scanlonian contractualism (the morality of principles no one could reasonably reject) — are not rival theories but are "climbing the same mountain on different sides." When properly formulated, they converge on the same fundamental moral principles.
Parfit died on January 1, 2017, in Oxford. He was also an accomplished photographer, specializing in images of Venice and St. Petersburg.
Methods
Notable Quotes
"{'text': 'Personal identity is not what matters.', 'source': 'Reasons and Persons', 'year': 1984}"
"{'text': 'When I believed that my existence was a further fact, I seemed imprisoned in myself. My life seemed like a glass tunnel, through which I was moving faster every year, and at the end of which there was darkness.', 'source': 'Reasons and Persons', 'year': 1984}"
"{'text': 'These three traditions are climbing the same mountain on different sides.', 'source': 'On What Matters', 'year': 2011}"
"{'text': 'We are not yet close to agreement. But that is because these questions are so difficult. That is no reason for despair.', 'source': 'On What Matters', 'year': 2011}"
Major Works
- Reasons and Persons Book (1984)
- On What Matters, Vol. 1 Book (2011)
- On What Matters, Vol. 2 Book (2011)
- On What Matters, Vol. 3 Book (2017)
Influenced
- Peter Singer · influence
- Nick Bostrom · Intellectual Influence
Sources
- Stanford Encyclopedia of Philosophy
- Derek Parfit's Reasons and Persons (Crisp, 1997)
- On What Matters (critical symposia)
- Parfit: A Philosopher and His Mission to Save Morality (MacFarquhar, 2011)
External Links
Translations
Discussions
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