Theories of Semantics on theWeb - Social Semantics: The Search for Meaning on the Web - page 98

Fig. 4.2 The descriptivist
theory of reference for URIs

Logical
Descriptions

A UR

While Hayes makes no claim that access to some web-pages via URIs is not
possible, he claims that such access to Web representations is orthogonal to the
question of what a URI could refer to, since “the architecture of the Web determines
access, but has no direct influence on reference” (Hayes and Halpin 2008).
Furthermore, Hayes's logical understanding of ambiguity parts path with natural
language understandings of ambiguity: Hayes claims that reference to resources is
completely independent of whatever Web representations can be accessed, even if
those contain logical expressions. While much credit should be given to Hayes for
creating a logical semantics for RDF, the problem of connecting these descriptions
to the world outside of the Web falls outside formal semantics and so opens up
a seemingly uncrossable abyss between the logical descriptions and sensory data.
One seemingly easy way out of this abyss is to revert to the doctrine of Russellian
direct acquaintance, also known as ostentation. In moments, Hayes himself seems to
subscribe to the logical atomist epistemology of Russell, as he says that “reference
can either be established by description or ostention” with ostention being defined
as the use of a Russellian demonstrative (like 'that' or 'this') identifying a particular
“patch of sense data” via a statement such as 'that is the Eiffel Tower' (Hayes 2006).
Since most of the things referred to by names are not accessible, reference can only
be determined by description, and these descriptions are inherently ambiguous as
regards any sense-data (Hayes and Halpin 2008).
As our example showed, RDF in general says so little inferentially that many
different models can satisfy almost any given RDF statement. Therefore, Hayes con-
siders it essential to ditch the vague word 'identify' as used in URIs, and distinguish