They Meet Themselves

Robert Heinlein's Bob Wilson and Poul Anderson's Jack Havig - and some other characters - meet themselves because they are time travelers. Anderson's Dunham (first name?) meets himself because a sufficiently advanced alien technology has duplicated him.

The two situations are not identical. One Wilson (and Havig) is younger than the other and becomes the other whereas both Dunhams are exactly the same age and will grow apart, neither becoming the other, although they start out as two instances of the same man like two copies of the same book. Can a type-token analysis apply to persons, with "Dunham" as a type that now has two tokens? (I am repeating terminology that I heard as a philosophy student.) If the second token was created after the death of the first, then the second would not be the first resurrected but would initially think that he was.

Such sf thought experiments might anticipate eventual technological advances. See Dead Men (Tell Tall Tales) here.