Board Thread:General Discussion/@comment-32182236-20180323153236/@comment-29855659-20180331114714

Just to be precise:

There's a second possibility: Chara is with the player, but not with Frisk. We don't know whether Frisk saw those memories as well, we only know that we did. After Frisk dies we can still hear Asgore saying "Stay determined", (as evidenced by tape 5, the "voice" and the fact that "Determination" used to be one of Asgore's leitmotifs in the early stages of the game (King Description)). Frisk is dead, but WE hear Chara's memories nevertheless. Chara is not with Frisk, but with us.

Other than that it's a good theory, especially because we see their memories more than once in the game. That we can see memories of other beings is also proven in the fight against Asriel, as we can see him and Chara - definitely one of Asriel's memories.