In a recent Philosophy of Nature class discussion prompt, the question was posed “Will our resurrected bodies be the same as our current bodies?” My answer to the prompt is as follows:
The Church’s teaching on this matter is that “The ‘resurrection of the flesh’ (the literal formulation of the Apostles’ Creed) means not only that the immortal soul will live on after death, but that even our ‘mortal body’ will come to life again” (Catechism of the Catholic Church, 2 nd ed., 990, ref. Rom 8:11). Furthermore, I rather agree with St. Thomas Aquinas’s reasoning that it’s inevitable that the same body would be raised, given that the very notion of “resurrection” pertains to something that had died being brought back to life—as opposed to being replaced (see Thomas Aquinas, Summa Theologiae, S-III, q. 79, a. 1).
This is well and good; but one might question how the exact matter that made up each person’s body could be brought back to life at the end of time. After all, as is said at the Ash Wednesday Mass, “you are dust, and to dust you shall return.” Our bodies dissolve; so, technically, some fragment matter that was in long-dead Uncle Edgar’s body when he died might later find itself in Cousin Janice’s body when she dies—or in any number of other people’s bodies when they’ve died. Which person’s body, then, would it be resurrected with?
I think the answer to this can relate back to something I was discussing in one of my posts on time travel: namely, that to God, all of time exists simultaneously (see my response to the prompt about whether God can change the past—and my reference to Hahn’s Understanding the Scriptures, 50). Thus, when He raises the dead on the last day, my idea is that He will essentially “reach into time” and “pick out” each person’s body from the time that those people died, “bring it back” to the present, and reunite it with that person’s soul.
I should also note that there’s another way of answering this prompt. In his First Letter to the Corinthians, St. Paul says that “what you sow [your mortal body] is not the body that is to be but a bare kernel of wheat, perhaps, or of some other kind; but God gives it a body as he chooses, and to each of the seeds its own body” (1 Cor 15:37-38, NABRE). Now, this almost makes it sound like we’ll be given an entirely new body made of entirely new matter; but I don’t think that’s what he’s really saying. Does a kernel cease to exist in order for wheat to exist? No … but you might analogize that it’s transformedinto the wheat, and that wheat is certainly different from the kernel. To quote Paul at greater length:
“Not all flesh is the same, but there is one kind for human beings, another kind of flesh for animals, another kind of flesh for birds, and another for fish. There are both heavenly bodies and earthly bodies, but the brightness of the heavenly is one kind and that of the earthly another. The brightness of the sun is one kind, the brightness of the moon another, and the brightness of the stars another. For star differs from star in brightness.
“So also is the resurrection of the dead. It is sown corruptible; it is raised incorruptible” (1 Cor 15:39-42).
Note especially that last sentence: the same “it” is both “sown corruptible” and “raised incorruptible,” which would seem to indicate the same matter behind both. So while the body resurrected will be of the same matter as that which dies, it will still be different—that is, it will be transformed: it will be glorified (see CCC, 997).