We ask that "self" if it feels intact.
If the answer is "yes", the conclusion is that the "sense of self" is intact.

Note that this doesn't mean the "self" is identical to the one before the operation, just that it feels itself(pun unavoidable) to be, which is really all the "sense of self" is.

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An emperor without enemies, a king without a kingdom, supported in life by the willing tribute of a free people.