In ch. 5 of The Empty Tomb: Jesus Beyond the Grave, Richard Carrier seeks to argue that Paul’s conception of the resurrection body of Jesus was a newly created body, not continuous with his earthly body. In the beginning of a section on the diversity of Jewish beliefs, he tells us that “at least one Jewish text imagines two bodies for Moses, one in a grave and one in heaven". (p. 107) He cites book VI of the Stromata by Clement of Alexandria:
When Moses was taken up to heaven, Joshua saw him twice: one Moses with the angels, and one on the mountains, honored with burial in the ravines.(Stromata 18.104.22.168-3)Clement of course wrote in the late second century. In a footnote, Carrier tells us that this passage about Moses is believed to trace back to the first century pseudepigraphon The Assumption of Moses. Aside from brief mentions in Clement, a quotation in Jude 9, and Gelasius’ Historia Ecclesiastica, the original text of The Assumption is now lost to us.
The extent to which Carrier seeks to use this passage is not clear to me. This quotation of Clement comes immediately after an argument to the effect that Jews believed in a postmortem existence of some sort outside the primary body, which is something I would not disagree with. But this entire chapter is an argument for his “two body” theory of Pauline resurrection. Perhaps Carrier seeks confirmation here for his view on the resurrection, in the sense that he supposes Moses was actually resurrected in a newly created body in this text. Perhaps he merely feels that it shows bodily survival outside the primary earthly body. If the latter is the case, the ambiguity here could be construed as misleading. Regardless, the reference in Stromata does not support either of these views.
The full text of book VI of the Stromata is available here. We will quote a larger portion of the section than Carrier did:
Rightly, therefore, Jesus the son of Nave saw Moses, when taken up [to heaven], double, -- one Moses with the angels, and one on the mountains, honoured with burial in their ravines. And Jesus saw this spectacle below, being elevated by the Spirit, along also with Caleb. But both do not see similarly but the one descended with greater speed, as if the weight he carried was great; while the other, on descending after him, subsequently related the glory which he beheld, being able to perceive more than the other as having grown purer; the narrative, in my opinion, showing that knowledge is not the privilege of all. Since some look at the body of the Scriptures, the expressions and the names as to the body of Moses; while others see through to the thoughts and what it is signified by the names, seeking the Moses that is with the angels.Right from the start we have an interpretive problem as the text of The Asssumption is no longer available for us to check the context of this obscure reference in Clement. But in Clement’s writings, this incident from The Assumption is quoted within the wider context of a section about hidden or sacred meaning in scripture, that is perceived only by some. The assumption of Moses before Joshua in which Joshua sees two of Moses - one with angels, one being buried - is read as an allegory of those who perceive the true or hidden meanings and those who do not. Joshua sees these things in some state where he and Caleb are "elevated by the spirit". It was a special revelatory privilege of the spirit realm granted to him, but not granted to Caleb who accompanies him and who merely saw Moses' earthly burial.
The main problem with Carrier’s use of this passage to support his “two body” theory, is that the text clearly does not say Moses had two bodies and it is entirely compatible with Moses going on to an intermediate spiritual state prior to the resurrection. The Moses "with the angels" that Caleb could not see, but that Joshua saw while they were "elevated by the spirit", is just as easily read as the spirit of Moses awaiting the resurrection of his body that has been buried, or, if the writer prefers immortality of the soul, just the mere ascending soul or spirit of Moses. It is not another “body” in the sense of Carrier's newly created resurrection body, or in any other sense. The last sentence of the above paragraph contrasts the "body of Moses" seen buried with "the Moses that is with the angels", neglecting to mention that the latter is a bodily state. So this passage offers no support for Carrier’s theory, does not imply a bodily existence outside the earthly body, and is very easily reconciled with the common scholarly notion of two-stage Jewish resurrection belief that Carrier is arguing against.