Peter van Inwagen sets forth one potential way to get around the decomposition problem, especially if one is a materialist. He offers this observation in the "Possibility of Resurrection":
"Perhaps at the moment of each man’s death, God removes his corpse and replaces it with a simulacrum which is what is burned or rots. Or perhaps God is not quite so wholesale as this: perhaps He removes for 'safekeeping' only the 'core person'--the brain and central nervous system--or even some special part of it. These are details."
Philosophers customarily have panned this suggestion, but there have been vigorous defenses of van Inwagen's simulacrum concept despite its apparent implausibility (by his own admission). See https://philpapers.org/rec/STERVI-3
On the other hand, Thomas Aquinas believes that resurrection of the dead is the uniting of our bodies with our putative souls. But how does God unite a body that's undergone decomposition with a soul that allegedly survives the death of the body? It seems like Aquinas imputes some type of miraculous work to God in this respect, and he reckons that all of our corporeal members will be restored in the resurrection even if they are not used by the resurrected "blessed ones." It appears that the resurrected body will even contain blood and normal organs, but that raises further questions.
http://www.ccel.org/ccel/aquinas/summa.XP_Q80_A1.html
http://www.ccel.org/ccel/aquinas/summa.TP_Q54_A3.html
N.T. Wright posits a transphysical body in the case of Jesus and I suppose for resurrected followers of Christ too. He contends:
The resurrection, as the eschatological event, has split into two (first Jesus, then, at his return, all his people—the further subdivision of the latter moment by Revelation 20 does not affect the present point).70 (2) The nature of the future resurrection body is further clarified: it will be incapable of dying or decaying, thus requiring a transformation not only for those already dead but for those still alive. This new mode of embodiment is hard to describe, but we can at least propose a label for it. The word ‘transphysical’ seems not to exist, surprisingly enough (one might have thought some enterprising ontologist would have employed it long since), and I proffer it for inclusion between transphosphorylation and transpicuous in the Oxford English Dictionary.71 The ‘trans’ is intended as a shortening of ‘transformed’. ‘Transphysical’ is not meant to describe in detail what sort of a body it was that the early Christians supposed Jesus already had, and believed that they themselves would eventually have. Nor indeed does it claim to explain how such a thing can come to be. It merely, but I hope usefully, puts a label on the demonstrable fact that the early Christians envisaged a body which was still robustly physical but also significantly different from the present one.
Whether it's the suggestion offered by van Inwagen, Aquinas or Wright, I personally take them all with a heaping grain of salt (cum grano salis). It is still not clear to me how personal identity can be preserved by either of the aforementioned accounts.
