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Persona #198

Derek Parfit

1942–2017
British philosopher; All Souls College Oxford; principal twentieth-century theorist of personal identity and reasons

Reasons and Persons — personal identity is not what matters; ethics is what we have most reason to do

Attribute Fingerprint

Rows where personas disagree are highlighted in gold. The full ontology grid (32 attributes) is shown.

Attribute Derek Parfit
Time · Extent Infinite
Time · Ontological Status Substantival
Time · Grain Continuous
Time · Freedom Non-Deterministic
Time · Traversability Linear
Time · Dimensionality One
Time · Direction Uni-directional
Space · Extent Infinite
Space · Ontological Status Substantival
Space · Curvature Flat
Space · Dimensionality Three
Space · Locality Local
Matter · Extent Infinite
Matter · Ontological Status Substantival
Matter · Conservation Conserved
Matter · Dimensionality Three
Matter · Locality Local
Observer · Time Instance Single
Observer · Space Instance Single
Observer · Knowledge Extent Mediated
Observer · Knowledge Retainment Partial
Observer · Physicality Embodied
Observer · Agency Active
Observer · Number Plural
Observer · Metaphysical Agency None
Observer · Moral Authority Reason
Observer · Theological Method N/A
Energy · Extent Infinite
Energy · Ontological Status Substantival
Energy · Conservation Conserved
Energy · Dispersibility Irreversible
Information · Ontological Status Substantival
Information · Cosmic Conservation Conserved
Information · Personal Conservation Non-conserved
Information · Granularity Continuous

Dimension-by-Dimension Evidence

What each persona's writings reveal about their stance on each of the six dimensions.

Time

Derek Parfit

Standard linear physical time; the question of identity over time is the central problem.

Space

Derek Parfit

Standard substantival space.

Matter

Derek Parfit

Standard substantival matter; persons are reducible to brains-and-bodies in psychological continuity.

Observer

Derek Parfit

Plural psychologically-continuous person-stages. Mediated knowledge through inference. No metaphysical agency.

Energy

Derek Parfit

Standard physics.

Information

Derek Parfit

Information not personally conserved beyond death; identity is a matter of degree.

Internal Tensions

Where each persona's working synthesis strains against itself.

Derek Parfit

Parfit's "Triple Theory" — that Kantian, consequentialist, and contractualist ethics converge — was contested even by his closest interlocutors (Scanlon's reply in OWM volume II is friendly but skeptical). The austerity of his life and the singular intensity of his philosophical commitments produced both his major contributions and the perception that he had narrowed the field of moral philosophy too sharply.