Curate, connect, and discover
Something I find really beautiful about this chapter is Atsushi subconsciously finding his tendency to rely on his emotions as a strength — he had no logical conclusion as to why the ADA members were alive, but instinctively, in his heart, he knew.
The same for Akutagawa — he knew that Akutagawa would remember, in his heart, with the doubt of his mind. I believe it was a quote Atsushi had said earlier, but I believe it's the core of his character — "The head may err, but never the blood".
The heart is a mysterious thing, because it makes sense without any logical basis. The heart is a trust, a senseless trust with a sense of clarity. Dazai in Atsushi's subconscious saying, "Feel strongly. That's what you do when you want to experience the past", brings me to believe that Atsushi has become better at living. Atsushi, by only living in the present, has become the only person fit to defy the space, because the present in the agreement of the past and future.
In other words, I believe Atsushi is the heart.