Identity is not what matters
The question whether I am some future person can have no answer, and that does not matter. What matters is psychological continuity and connectedness, which come in degrees and can branch.
The Twentieth Century to Today · 1942 – 2017
Derek Parfit
帕菲特 · Derek Antony Parfit
Personal identity is not what matters, psychological continuity is; future people count as much as present ones; moral philosophy is a young science and secular ethics has only begun. He wrote two books in his life.
My life seemed like a glass tunnel, through which I was moving faster every year. When I changed my view, the walls of my glass tunnel disappeared. I now live in the open air.
Source: Reasons and Persons, §95
Parfit was born in Chengdu to missionary doctors who returned to England when he was one. He studied history at Eton and Balliol College, Oxford, meant to be a poet, turned to philosophy while visiting Columbia and Harvard in 1965, and in 1967 became a fellow of All Souls College, Oxford, where he remained for life, never taking a doctorate and rarely leaving. He worked with extreme concentration, reportedly ate the same food and wore the same clothes every day, read while walking and cut sleep to a minimum.
The 1971 paper 'Personal Identity' and Reasons and Persons (1984) made his reputation. With thought experiments of teleporters, split brains and cell-by-cell replacement the book argued that 'I' am not a deep further fact persisting through time, that personal identity consists only in psychological continuity and connectedness, and that since these relations come in degrees and can branch, 'identity is not what matters'. He said the conclusion freed him from the fear of death: death is only the breaking of relations, and the wall between me and my future self is the same kind of wall as between me and other people. This 'reductionist' view of the self led him to Buddhism.
Part four of Reasons and Persons founded 'population ethics': if total happiness is the only standard, a world of tens of billions of people whose lives are barely worth living is better than a world of a few extremely happy people, the 'repugnant conclusion', which he believed must be rejected but could find no coherent theory to reject. He also posed the 'non-identity problem': our decisions about the future change who will be born, so future people cannot complain that our choices harmed them, though the choices can plainly be wrong. These problems are the starting point of climate ethics and longtermism.
He then spent twenty-seven years on On What Matters, published in two volumes in 2011 and a third in 2017. Its aim was to show that Kantianism, Scanlon's contractualism and rule consequentialism, in their best forms, agree, so that ethics is converging on truth, against moral nihilism and subjectivism. Without objective reasons, he thought, 'my life would have been wasted'. His severe perfectionism made finishing anything hard, and students and colleagues received hundreds of pages of comments from him. He died in his sleep in January 2017, having answered comments the day before.
Key Ideas
The reductionist view of the self
A person is no deep further fact beyond body and experiences, as a nation is nothing beyond citizens and territory. Seeing this, the wall between self and others grows thinner.
The repugnant conclusion
For any happy population there is a larger one whose lives are barely worth living that is better in total. We must reject the conclusion, but no coherent theory has been found that rejects it.
The non-identity problem
Our policies determine who will be born. A person who exists only because of our bad decision cannot say they were harmed, since otherwise they would not exist at all. This challenges person-affecting morality.
Climbing the same mountain
Kantianism, contractualism and consequentialism agree in their best forms. Ethical disagreement is smaller than it looks, and moral truth can be discovered.
Secular ethics has only begun
Ethics that does not rely on religion is only two centuries old and still young. It is too early to believe there are no moral truths; we have only begun to inquire.
Influenced by
- David Hume
His theory of personal identity is the contemporary version of Hume's 'bundle': no deep self, only psychological continuity, which can come in degrees and can branch.
- Immanuel Kant
On What Matters tries to show that Kantianism, contractualism and consequentialism are 'climbing the same mountain on different sides' and will meet at the summit.
- John Stuart Mill
He remade utilitarianism from a doctrine about happiness into a doctrine about reasons, and pushed its population ethics to the 'repugnant conclusion'.
- John Locke
Locke grounded personal identity in memory; with thought experiments of split brains, teleporters and gradual replacement he showed that identity itself is not what matters.
- John Rawls
- Thomas Nagel
Influenced
- Peter Singer
Friends and interlocutors at Oxford; late in life, in The Point of View of the Universe, he accepted Parfit's objective reasons and moved from preference to hedonistic utilitarianism.