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The Ship of Theseus puzzle asks: after replacing all parts of a ship over time, is it still the same ship? A reassembled version of the original parts is also presented. The puzzle assumes identity is a static, intrinsic property. This short note shows, using only elementary arithmetic, that identity is not intrinsic. It depends on the frame of observation.
Define three sequences of symbols:
Observe identity under different frames.
is not identical to (first element differs).
Neither is identical to .
Result: All three are different.
and contain the same set .
contains .
Result: , different.
In , any two elements are identical.
In and , the pair differs; the pair differs; the pair differs.
Result: has more internal identity than or .
Result: All three are identical.
Identity is not an intrinsic property of the sequences.
The same sequences yield different identity judgments depending on the frame:
order
set
partial pairs (C has more identity)
arithmetic result
There is no “real” identity. There is only identity relative to a chosen frame.
The Ship of Theseus is not a paradox. It is a failure to declare the frame.
Frame as continuous history (order of replacements) Ship A (repaired) is the Argo.
Frame as original material (set of parts) Ship B (reassembled) is the Argo.
Frame as function (sailing, purpose) both are Argo.
Frame as internal identity (same wood for all parts) partial for both ships.
No frame is more “real” than another. The puzzle disappears once the frame is declared.
Identity is not intrinsic. It is context‑dependent, observer‑relative, and frame‑explicit. The arithmetic model with 1, 2, and 0 demonstrates this concretely. The Ship of Theseus could be a case of missing frame declaration.