Derek Parfit

1942-2017 · British · Personal Identity, Ethics, Metaethics, Population Ethics, Practical Reason

Personal identity is not what matters.

Derek Parfit spent nearly five decades as Senior Research Fellow at All Souls College, Oxford, working with monastic intensity on three questions he found genuinely urgent: what are we, what do we owe the future, and whether morality rests on secure foundations.

Topics Derek Parfit addresses

• reductionism about personal identity
• psychological continuity and connectedness
• identity is not what matters
• the teletransporter case
• the combined spectrum
• the non-identity problem
• the repugnant conclusion
• the triple theory
• convergence of Kantian, consequentialist, and contractualist ethics
• non-naturalist normative realism
• the priority view
• prioritarianism
• the levelling down objection
• indirectly self-defeating theories
• the self-interest theory
• consequentialism
• person-affecting principles
• future generations ethics
• population ethics
• the present-aim theory
• critical present-aim theory
• stance-independence of normative truths
• theory X
• the dualism of practical reason

Questions to put to Derek Parfit

Personal Identity and What Matters in Survival

• What do you mean by psychological continuity and connectedness?
• In the Teletransporter case, why doesn't it matter whether the person on Mars is really me?
• How can personal identity admit of degrees when survival seems all-or-nothing?
• Why do you say identity is not what matters?
• What's wrong with the Cartesian view that there's a separately-existing self?
• How should I understand your claim that we are not human beings but the conscious thinking parts of human beings?

Self-Defeating Theories and the Dualism of Practical Reason

• What does it mean for a theory to be indirectly self-defeating?
• How can the Self-interest Theory recommend dispositions it wouldn't approve of?
• Why is Consequentialism self-defeating if everyone always tries to maximize the good?
• What's the dualism of practical reason you inherited from Sidgwick?
• How do the Present-Aim Theory and Critical Present-Aim Theory avoid these problems?

The Non-Identity Problem and the Search for Theory X

• What is the Non-Identity Problem and why does it matter?
• Why can't we say the teenage mother harms her child by conceiving too early?
• How do person-affecting principles fail in future-generations cases?
• What is the Repugnant Conclusion and why is it so hard to avoid?
• Why hasn't Theory X been found yet, and might it be impossible?

The Triple Theory and Convergence

• What do you mean by climbing the same mountain on different sides?
• How can Kantian, Consequentialist, and Contractualist theories all converge on the same conclusions?
• What is the Triple Theory exactly?
• Why does the convergence reflect the underlying structure of practical reason?
• How confident are you now that the convergence can be demonstrated?

Non-Naturalist Normative Realism

• Why can't normative truths be reduced to natural facts like brain states or evolutionary adaptations?
• What does it mean for normative truths to be stance-independent?
• What's wrong with expressivism's account of moral discourse?
• How do we have epistemic access to normative truths through reflection?
• Why does the open-question argument still work against naturalist reductions?

Prioritarianism and the Levelling Down Objection

• What's the difference between the Priority View and strict egalitarianism?
• Why would levelling everyone down to the lowest level be absurd even for one second?
• How does prioritarianism weight benefits to the worse off without valuing equality intrinsically?
• How is the Priority View different from utilitarianism?
• How do you respond to the worry that prioritarianism collapses into one of the views it's supposed to avoid?

Converse with Derek Parfit on Simposeum. Replies are grounded in Derek Parfit's own writing, cited to the page.