I understand metonymy generally. A part or aspect represents the whole; e.g., "wheels" stands for
vehicle, "crown" stands for monarchy. In the subject case, the writer, although not a part of the
entirety, claims to BE the entirety. What form of metonymy could that be?
That's synecdoche. Metonymy is more generally one name in place of another. For example, I can call my daughter "honey" when she is clearly not edible, except perhaps from the point of view of a Grizzly Bear.
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