Consider cessationist models of resurrection. On these, the person who is saved completely ceases to exist at death--not even a core of the person, like a soul, continues to exist. But then some time later God resurrects the person to full existence, an existence that involves complete human fulfillment for an infinite amount of time.
Many Christian materialist models are cessationist. Perhaps God gathers the matter and forms it into something close to what the body was like at death in a way that ensures personal identity. Perhaps God gives the body at death a miraculous power of causing a future body at the time of resurrection. Or perhaps God arranges for the pre-death body (or some part of it) to time travel to the time of resurrection and replaces the original body with a simulacrum which we bury.
Now consider this argument:
- Death is always a great harm for the person who dies.
- Death is not a great harm on cessationist models.
- So cessationist models are false.
Maybe the harm is that there was a thousand years without Francis. But that sounds like a harm for the world, not a harm for Francis. Moreover, there were billions of years without Francis before Francis was conceived, and that wasn't bad for Francis. As far as Francis is concerned, he basically time-traveled by a thousand years into the future (cf. Merricks). Maybe we can worry that his heavenly existence is short a thousand years, but that seems mistaken: it's infinite, after all, and infinity less a thousand is no shorter than infinity.
Let me try to make the point perhaps more vividly. Consider two people, Hyacinth and Agnes. Both of them go to sleep in the evening at age 80, and neither has dreams.
Agnes has a heart attack in her sleep. But at the very moment that she would otherwise have been dead, the resurrection happens, so she never dies. Instead, she wakes up to heavenly life. The badness of death didn't touch Agnes since she never died.
A much more complicated thing happens to Hyacinth. He, too, has a heart attack in his sleep. But one second before he was going to die, he time-travels to a time one second before his conception (or whatever point marks the beginning of a human being's life). He lives for one second then, albeit asleep, and then dies. Eighty years later the resurrection happens. Coincidentally, the resurrection happens the moment right after Hyacinth was whisked back in time.
Hyacinth died but Agnes didn't. However, notice that Hyacinth actually exists at every moment of time from his conception onward. He also has that weird little extra one second of existence before his conception due to time travel. But surely that's insignificant. It doesn't seem that Hyacinth is noticeably worse off--or even at all worse off--than Agnes.
But now compare Hyacinth to Francis, who dies in his sleep 80 years prior to the resurrection without any time travel. Both Hyacinth and Francis die 80 years before the resurrection. The only difference is that for Hyacinth, that death 80 years before the resurrection takes place just before Hyacinth's conception. But surely that doesn't make Hyacinth significantly better off than Francis. Francis and Hyacinth are roughly on par in how well off they are. And by the same token, Francis and Agnes are roughly on par. But Francis dies and Agnes doesn't. So death isn't bad for you on the cessationist model.
What models of resurrection make death be bad for you? I think it's models on which you continue to exist between death and resurrection but in a way that is importantly diminished. For instance, a dualist can say: It's really bad to lose your arms. But when you die, you lose your arms, so dying is really bad. And you also lose your legs, your eyes, your ears, etc. (You even lose your brain though maybe God miraculously supplies the mental functions that we normally need a brain for?) Granted, you are more than amply compensated by union with God, but that a bad is compensated for does not make it not be bad. Similarly, a non-cessationist materialist could think that God snatches your brain out of your body just prior to death, replaces it with a replica, and then makes you literally be a brain in a vat in heaven. Such a non-cessationist materialist would be able to say why it is really bad for you to die, because you lose your arms, legs, eyes, ears and most of your body, except your brain.