A few thoughts on why sometimes it feels impossible for other people’s minds to exist.
I think a lot about the subjective conscious experience of other people. Something about it feels fundamentally impossible. I think part of that feeling is explained by the “Bigness” of one’s own conscious experience. The ‘edges’ of your experience ostensibly touch the edges of the universe. By virtue of your experience of reality being, well, experienced by you, it feels as if in some way reality is wrapped up within your experience of it.
Once you have that experience - of your own perception encompassing an infinite universe - it becomes difficult to grasp that there are other entities having the very same experience. It feels like a mathematical impossibility. Even though you know this isn’t really constrained by actual laws of math and physics the tension remains, and I suspect contributes to little doses of solipsism.