I’m only on day 9 of Ajahn Brahmali’s course on DN1 Brahmajalasutta, so my understanding is embryonic, but this is as I currently understand…
In addition to the ‘self’ discussions upstream in this thread, the other problem with ‘eternalism’ and ‘annihilationism’ (and the other 60 views in DN1) is that they all have feeling as a condition. There’s at least two problems with that: [1] feelings are annica therefore unstable and unsatisfactory. When we’re happy-happy-joy-joy, we want to believe in eternalist views. When we’re all dukkha’ed up, we want to believe in annihilationist views. (If ‘I’ am Eternal, then so is my suffering) Problem [2] is that feeling → grasping → misery and grief → around we go again.