Do annihilationism and universalism argue against eternal life? Annihilationists and universalists argue that the Greek word translated "eternal" (aionion/aionios) is more appropriately translated "eon-like", and thus New Testament terms like "eternal fire/punishment" (in e.g. Matt 18:8, 25:46) should be interpreted to mean long lasting but still finite fire and punishment.

Given that argument, do annihilationists and universalists have any New Testament basis for believing that "eternal life" is really eternal and not merely long lasting?
The views expressed below are not my own, but your question merits an answer that I hope represents annihilationism as an annihilationist might. I will seek to demonstrate you are correct in believing some annihilationists resort to alternate translations about hell which present difficulties for the traditional understanding of verses about heaven. Nevertheless, understood consistently, annihilationists can still believe that heaven is an eternal state.

1. Some annihilationists believe in translating references to eternity as 'eons' or 'ages'

Even annihilationists will admit that certain verses in scripture can be difficult to interpret from their perspective. Greg Boyd writes:


  The most difficult passages for annihilationists to explain are Revelation 14:10-11 and 20:10. These passages speak of the wicked being tormented “day and night forever and ever.”


The solution seems to be a matter of translation, accompanied, as I will suggest below, with a paradigmatic shift in the way we think about all such references to the 'temporal' nature of hell. Boyd Goes on to suggest that 'forever and ever' doesn't have to be a reference to eternity.


  The phrase “forever and ever” can be translated “for ages upon ages” which implies an indefinite, but not necessarily unending, period of time.


This leads the a difficulty regarding verses about heaven. If the same trick is used in verses like Matthew 25:46 to make "eternal punishment" into something less than eternal, it seems to undermine the eternality of "eternal life" mentioned in the exact same verse using the exact same word aiōnios.

2. Annihilationists can still believe in the eternity of the heavenly reward

Although seeming to present a difficulty if that were how Matthew 25:46 is translated that way, annihilationism both offers a new translation and an entirely new way of understanding the point of this verse. Boyd also writes:


  Now, Scripture certainly teaches that the wicked are punished eternally, but not that the wicked endure eternal punishment. The wicked suffer “eternal punishment”(Mt 25:46), “eternal judgment” (Heb 6:2) and “eternal destruction” (2 Thess 1:9) the same way the elect experience “eternal redemption” (Heb 5:9, 9:12). The elect do not undergo an eternal process of redemption. Their redemption is “eternal” in the sense that once the elect are redeemed, it is forever. So too, the damned do not undergo an eternal process of punishment or destruction. But once they are punished and destroyed, it is forever. Hell is eternal in consequence, not duration. The wicked are “destroyed forever” (Ps 92:7), but they are not forever being destroyed.


Therefore, the solution for an annihilationist isn't merely to translate words like aiōn as 'ages' but to also suggest the meaning of temporal references to eternity - both heaven and hell - is not in fact primarily temporal but descriptions of finality and intensity. Therefore, while 'complete' destruction implies full and just punishment that doesn't need to be eternal, to be 'completely' redeemed places one entirely outside of the clutches of sin, death, and the devil meaning that even without the use of the word eternal, the redeemed are implicitly redeemed forever because they have been redeemed 'completely'. This certainly softens the temporal references to the lasting eternal state of the redeemed of heaven, but it also seems to do justice to the different connotations a descriptor can take when applied to the different concepts of 'destruction' and 'life'.

I am not an expert in biblical Greek so I suppose an expert could mount a critique of the degree to which this explanation depends on English translations and grammar, but this is the way Boyd, as an annihilationist, explains his perspective.