Current scholarship demonstrating the non-historicity of the Pentateuch includes discussion of the “Song of Moses” at Deuteronomy 32:1–43, a lengthy recitation clearly not composed by a historical Moses.
32 Listen, you heavens, and I will speak; hear, you earth, the words of my mouth.
2 Let my teaching fall like rain and my words descend like dew,
like showers on new grass, like abundant rain on tender plants. Deuteronomy 32:1-2
Concerning the song’s attribution to Moses as asserted in Deuteronomy 31:19 and 31:22, biblical scholar Dr. Paul Sanders remarks that “present-day scholars almost universally deny the historicity of these claims” and that “Deut. 32 would have been composed in a later period of Israel’s history.”
19 “Now write down this song and teach it to the Israelites and have them sing it, so that it may be a witness for me against them. Deuteronomy 31:19
22 So Moses wrote down this song that day and taught it to the Israelites. Deuteronomy 31:22
In his monograph The Provenance of Deuteronomy 32, Sanders provides the scholarship for this contention of non-Mosaic origin for the “Song of Moses.” Likewise, we can assert that the rest of the Pentateuch too was not written by a historical Moses but was composed many centuries after his supposed existence, for a variety of reasons, not the least of which was political, to compete with the founding myths of other nations.
Just as in the Exodus themes, Sanders demonstrates that elements of the Song of Moses are pre-Mosaic, emanating from Ugaritic/Canaanite mythology. These pre-Israel and mythical elements in turn were drawn upon to flesh out of the Exodus story.