Full Idea
There is no natural border between inner and outer.
Gist of Idea
There is no natural border between inner and outer
Source
Gilbert Harman ((Nonsolipsistic) Conceptual Role Semantics [1987], 12.3.4)
Book Reference
Harman,Gilbert: 'Reasoning Meaning and Mind' [OUP 1999], p.224
A Reaction
Perhaps this is the key idea for the anti-individualist view of mind. Subjectively I would have to accept this idea, but looking objectively at another person it seems self-evident nonsense.