Well, sort of. Obviously bodies return to the elements (despite morticians’ efforts to the contrary), and eventually, over hundreds and thousands of years, it’s all atoms and molecules. I heard of a case where they went to exhume someone, and there was nothing left — no coffin, no bones, no teeth, no hair, nothing, just soil (and, I think, what little metal there had been in the coffin, nails, handles, etc.). There are soils and environments where such a thing is possible. Everybody will be “put back together” in a way we don’t understand, but it will not be a “new” body, it will be the “old” body reconstituted.
A more precise way of putting it might be to create a time frame that is utterly unrealistic, just to illustrate the point:
- Organ is taken from donor on Day 1
- Organ is received by patient on Day 1
- Donor is canonized a saint on Day 2 (talk about “santo subito”!)
- Recipient dies in mortal sin and, regrettably, goes to hell on Day 3
- The Second Coming and the end of days takes place on Day 4
- The dead rise from the grave, and soul and body are reunited on Day 4
- The General Judgment takes place on Day 4
Both saint’s body and patient’s body have just barely begun to decompose, and the patient still has the saint’s liver in his body. What happens then?