Derek Parfit

Reasons and Persons

1. IDEA 1

   Some theories defeat themselves

   Parfit begins by showing that some moral theories can be self-defeating: if everyone follows them, everyone ends up worse off by the theory's own standards. Common-sense morality, he argues, sometimes has this problem.

2. IDEA 2

   Imagine a teleporter

   Parfit uses thought experiments, such as a teleporter that destroys your body and creates an exact copy elsewhere. He asks whether the copy is really you, testing our ideas about personal identity.

3. IDEA 3

   Persons are not separate essences

   Parfit argues that a person is not a deep, separate self but consists of connected physical and mental events. This view, called reductionism, changes how we think about identity. Selves are less solid than they seem.

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