Body and Soul in Ancient Philosophy

156
David Sedley
other hand tripartite. Subsequently, in the Timaeus, he explicitly imposed
that restriction, limiting immortality to the rational soul, but
even that was not enough to secure the rational soul’s essential immortality,
since both the world soul and the human rational soul are there
presented as divine artefacts, fitted together by the mathematically precise
interweaving and structuring of six components (35a1 –b4,
41d4 – 7). Reason’s core ability to interrelate being, identity and negation
(or ‘difference’) – explored in another late dialogue, the Sophist –
requires that reason itself reflect these objects in its own structure. Consequently,
the new move of restricting the rational soul to the kind of
immortality that a creator could bestow upon it in constructing it is
fully in keeping with Plato’s thought at the time.
Earned immortality
Are transitions possible across the boundaries between acquired and essential
immortality, or between either of those and mortality? It seems
reasonable to assume that nothing ever moves down the scale. If something
has immortality as part of its essence, it could not lose that essential
immortality without ceasing to exist, which is precisely what, being immortal,
it could never do. 14 Again, if something with essential or conferred
immortality could lose it and thus become mortal, then it never really
possessed immortality in the first place. Immortality ought to be irreversible.
This corresponds to the fact that virtually nobody in the Greek
mythological tradition, once immortal, loses his immortality – not even
Tithonus, even though he most bitterly regretted acquiring it in the first
place. 15
immortality seems to me underdetermined by the text. Soul may well be essentially
self-moving (245e2 – 6), but it is much less clear (245c5 – e2) that the selfmoving
is essentially immortal, and not merely protected by divine providence.
14 At Plt. 270a4 – 5 the myth speaks of the world “acquiring a restored immortality”.
This locution, whose enigmatic nature is of a piece with the entire myth,
may seem to imply that the world first loses immortality, then recovers it. But if
it is guaranteed to ‘recover’ its immortality in endlessly repeated cycles, it is presumably
not fully losing it even in the intervals.
15 At most, in one or two exceptional cases (my thanks to Ben Henry for alerting
me to them), Zeus may allow immortality to be transferred (Chiron) or otherwise
redistributed (the Dioscuri), a device which itself confirms that immortality
could never simply be cancelled. For some familiar myths of apotheosis, cf.
O’Brien 1984, 200 – 201.