> Externalism - that having or not having true beliefs are dependent on
> the environment.
>
> Putnam's classic argument for externalism starts with a thought
> experiment: imagine that water comes in two forms - H2O on earth, and
> XYZ on twin-earth. So, when both earthmen and twin-earthmen (who are
> physically alike) say that 'water quenches thirst' they are expressing
> different beliefs. This is externalism's claim.
>
> There are many arguments against this idea - that the content of a
> belief is dependent on external factors. The opposite argument is
> internalism - that beliefs are an intrinsic property of the individual.
>
> Both externalism and internalism are wrong, it seems to me. First, for
> the externalist, there is no way that either H2O or XYZ can be
> identified except by water. It is water that allows us to distinguish
> H2O or XYZ from the cup that holds it, or the river from the river-bed.
>
> For the internalist position, we have simply an environmental
> minimalism, veiled by the term 'psychological'. The internalist merely
> limits the extent of the externalist environment to the body. The body
> then, inexplicably, becomes the receptacle of thoughts (as a
> 'psychological' condition), yet the problem of the mind-matter,
> internal-external interface, remains.
>
> But we can deliver a double-whammy against both positions. Both
> internalism and externalism rest on classical notions of belief. The
> ontological ambiguity of the term 'belief' is historically entrenched,
> and you will be hard put to make sense of it. All we need claim is that
> a 'belief' is neither internal nor external but is a public document. An
> ontological or physical placement of that document is irrelevant to the
> use we make of it. Where there is only one proposition publically or
> individually presented, such as 'this is water', then we can have no
> belief about the matter.
>
> For example, we have no belief or knowledge that one and one are two -
> they simply are two, for no alternative is on offer. Granted, we may
> create an alternative - that, for example, in quantum reality one and
> one may not be two; or that we are mad and cannot make sense of
> addition. But whether the alternatives we create are ontological, or
> mental, etc., one and one are two per se is neither an internal belief,
> nor an external truth. However, once we are given another alternative -
> that one and one are not two, then we may decide on the evidence which
> is right - we would come to a pragmatic decision, i.e. have a belief,
> about which is right. But coming to a pragmatic decision, or believing
> which of two or more propositions are the right ones, is not a property
> of the propositions that make up the belief.