Full Idea
It is hard to think of myself as being identical with my brain. If my brain is to be split, with one half miserable and the other half euphoric, my expectations can take no form, as my idea of myself doesn't allow for divisibility.
Gist of Idea
I can't even conceive of my brain being split in two
Source
Thomas Nagel (The View from Nowhere [1986], III.4)
Book Reference
Nagel,Thomas: 'The View from Nowhere' [OUP 1989], p.45
A Reaction
Nagel is trying to imply that there is some sort of conceptual impossibility here, but it may just be very difficult. I can think about my lovely lunch while doing my miserable job. Does Nagel want to hang on to a unified thing which doesn't exist?