[ExI] The second step towards immortality

[Anders Sandberg]

On 11/01/2014 12:01, Ben wrote:
> [*]  This is an interesting topic in itself:  When does a theoretical
> possibility become invalid because it's not actually a real
> possibility?

Ah, you have stumbled upon something philosophers discuss and disagree 
about:
http://plato.stanford.edu/entries/thought-experiment/#SysExp

I think the key link is that the world of the thought experiment must 
overlap enough with our real world (in the relevant aspects) that it 
allows us to generalize from the result of the thought experiment to 
other, non-thoughtexperimented aspects of the world.

For example, we can make some thought experiments about worlds where 
humans are very different kinds of creatures (like Parfit's 
amoeba-people): many conclusions about personal identity from these 
experiments do not seem to carry over to our world since human personal 
identity is fairly strongly linked with us being non-dividing. But a 
thought experiment about how technological development would look on a 
much larger and populous Earth (Bostrom's super-Earth) does seem to map 
rather nicely to the real world: labour pool does have an effect on 
research, while the radius of the planet is irrelevant.

Ned Block's GLUT argument overlaps rather strongly with our world in the 
relevant parts: when thinking about whether machines could have 
consciousness or intelligence the relevant aspect is not whether there 
is some computational trick that can hide vast amounts of memory inside 
a realizable box or not, but whether the mechanism of looking up 
responses can be said to have those properties. After all, we could have 
been living in a universe that looked like ours but had those extra 
computational resources (just like my trapdoored addition function is 
just like normal addition, with one exception).

Real world --------  Part of the real world ---------- Real world
                      Real things: A, B, C
                        A     A     A          Inferred: D,E,F,G,H
              Mapping   |     |     |
                        V     V     V
                      Thought experiment
                      Imagined things: a, b, c
                      Concluded pattern: d, e, f

Of course, there are many shades of possible worlds too:
http://plato.stanford.edu/entries/possible-worlds/



-- 
Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University