In this scene the narrator is reading in a secluded area. He wants to stay away from everything, free from his duties.
On page 90:
"And then my thoughts, too formed a similar sort of recess, in the depths out which I felt that I could bury myself and remain invisible even while I looked at what went on outside."
I think I've started feeling like this more and more as the pandemic drags on. I even got a weird metafictional moment as I read this in the sauna and recognized how my own isolation in there caused a very similar reaction: a spiraling inward set of thoughts pulling me away from the real world.
Reading Proust can have this effect where you get lost in your own thoughts. As I've watched the outside world in quarantine, I've started to feel this invisibleness. I've hardly spoken to many people I knew. They've just left my life somehow, leaving me invisible.
It's the classic philosophical problem of solipsism. We can only be sure of our own existence. This means others can't be sure of yours. You can just disappear. Out of sight, out of mind as the saying goes. But then: out of mind, out of existence.
Rather than get lost in this problem, the narrator actually thinks of it as an almost spiritual experience. There's a complicated interaction between our own consciousness and the external world.
We perceive the world through our senses, but these are just perceptions: not the thing itself. We can't ever know the thing itself.
In a quite literal interpretation of physics, we can't even ever touch a thing because the electrons in our fingers repel the electrons in the object before physical contact is made.
We have impressions of the world, but how real is it? We bury ourselves in our thoughts and experiences while everything else moves on with or without us.
If we get too trapped by these thoughts and feelings, then it's sure to leave us behind. We're sure to become invisible to all others.
It's important to pull out of this for moments to actually live in the world.