more on this theme | more from this thinker
Full Idea
If the famous brain in a bottle is your exact duplicate in brain states, but only experiences the computer's virtual reality, so that you share no objects of acquaintance, then according to externalists you share no beliefs whatsoever.
Clarification
The 'brain in a bottle' has not body, only inputs from a computer
Gist of Idea
If you don't share an external world with a brain-in-a-vat, then externalism says you don't share any beliefs
Source
David Lewis (Lewis: reduction of mind (on himself) [1994], p.424)
Book Ref
'A Companion to the Philosophy of Mind', ed/tr. Guttenplan,Samuel [Blackwell 1995], p.424
A Reaction
A very nice reductio ad absurdum of the idea that all concepts and beliefs have external meaning.
| 3990 | The whole truth supervenes on the physical truth [Lewis] |
| 3989 | I am a reductionist about mind because I am an a priori reductionist about everything [Lewis] |
| 3991 | Where pixels make up a picture, supervenience is reduction [Lewis] |
| 3992 | Folk psychology makes good predictions, by associating mental states with causal roles [Lewis] |
| 3993 | Arguments are nearly always open to challenge, but they help to explain a position rather than force people to believe [Lewis] |
| 3994 | Human pain might be one thing; Martian pain might be something else [Lewis] |
| 3995 | A mind is an organ of representation [Lewis] |
| 3996 | Folk psychology doesn't say that there is a language of thought [Lewis] |
| 3998 | If you don't share an external world with a brain-in-a-vat, then externalism says you don't share any beliefs [Lewis] |
| 3997 | Nothing shows that all content is 'wide', or that wide content has logical priority [Lewis] |
| 3999 | A spontaneous duplicate of you would have your brain states but no experience, so externalism would deny him any beliefs [Lewis] |
| 4000 | Wide content derives from narrow content and relationships with external things [Lewis] |