Yes, I think we are capable of understanding everything in the universe, at least theoretically; we must assume that or we will just give up trying to understand.

I can understand the desire to stay optimistic and hope we can understand everything so that we don't just give up on scientific inquiry. But I think that claim might be too strong and therefore hard to defend. To claim that there's nothing outside our eventual theoretical understanding seems to be saying that we could one day become God, right?

I would like to suggest that maybe the more we study science, the more we become humbled at the size and the grandeur and strangeness of this universe. And maybe that opens up the possibility that there are some things or some event in the universe that we won't understand. But I hope that our conversation has given us some food for thought.