Reddit reply in r/AcademicQuran: how were the sects of islamic theology formed — September 24, 2024 · loplsyw | Ali Shukri Amin

I think the best way to understand proto-Sunnism, at least my usage of it here, is the group which had the composite elements to ultimately BECOME Sunnis at a later stage. This doesn't mean they had all of the same exact beliefs or scriptural sources or political positions. Sunnis are also not a monolith.

What coalesced after the Umayyad dynasty was Sunnism proper. After that it's quite literally called Sunnism and discussed as such internally and by other groups.

There's some things that make Sunnis unique, and many of them have to do with opposing or not taking positive stances on things other groups felt strongly about.

The earliest Muslims saw the Quran as God's literal unerrant verbatim words. This is contrast with the Ismailis for example. They also venerated the aphorisms, stories, and behaviors of the Prophet. This is in contrast with Quranists or Falasifa. There was an early group of traditionalists relating these stories about the Prophet, whether reliable or not, whether the asanid are a backprojection or not.

Additionally, Sunnis identified with the major companions of the Prophet early on, even if they took sides. The proto-Sunnis didn't totally excommunicate any of the companions, even if they leaned towards Mu'awiyyah or Ali.

What is distinct is: the Qur'an and it's recensions (all of the major qurra were either Sunnis or proto-Sunnis), the body of stories that became the Sira literature (Maghazi Urwa, Waqidi, ibn Hisham), development of fiqh, a polemical theology, and a respect for pietism/mysticism.

Qadiris, Khawarij, early Shia, Mutazilah - for the most part where not involved in the codification of the Qira'at, major Sirah works, the famous hadith books, or the fiqh schools. By the time Kitab al-Sab' is written, it's taken for granted that all the Qurra are neccesarily considered Sunnis. Early Sirah works are monopolized by proto- or full-fledged Sunnis. Shia hadith works are more of a response to the Sunni corpus. There was certainly Mu'tazilite fiqh but they actually attributed themselves to Abu Hanifa (mostly, some like Qadi Abd al-Jabbar were Shafi'i).

That's not to say that these other groups didn't have intellectual output. They certainly did. However, it wasn't in the form of these identifying hallmarks of early Sunnism. Proto-Sunnis had the building blocks to establish it.