Architecture of theWorld WideWeb - Social Semantics: The Search for Meaning on the Web - page 41

map-maker, who has some historical connection to someone who actually travelled
the streets of Paris and figured out where the Eiffel Tower was. In this regard, our
definition of representation is very much historical, and the original presentation of
the referent can be far back in time, even evolutionary time, as given by accounts
like those of Millikan (1984). One can obviously refer to Gustave Eiffel even though
he is long dead and buried, and so no longer exists.
Also, the referent of a representation may be what we think of as real-world
patches of space and time like people and places, abstractions like the concept
of a horse, to unicorns and other imaginary things, future states such as 'see you
next year,' and descriptive phrases whose supposed exact referent is unknown, such
as 'the longest hair on your head on your next birthday.' While all these types of
concepts are quite diverse, they are united by the fact that they cannot be completely
realized by local information, as they depend on partial aspects of an agent's local
information, the future, or things that do not exist. Concepts that are constructed
by definition, including imaginary referents, also have a type of 'presence,' it is
just that the 'presentation' of the referent is created via the initial description of the
referent. Just because a referent is a concept - as opposed to a physical entity - does
not mean the content of the representation cannot have an meaningful effect on the
interpreter. For example, exchanging representations of 'ghosts' - even if they do
not quite identify a coherent class of referents - can govern the behavior of ghost-
hunters. Indeed, it is the power and flexibility of representations of these sorts that
provide humans the capability to escape the causal prison of their local environment,
to plan and imagine the future.

2.3 The Principles of Web Architecture

It is now possible to show how the various Web terms are related to each other
in a more systematic way. These relationships are phrased as five finite principles
that serve as the normative Principles of Web architecture: The Principles of
Universality, Linking, Self-Description, the Open World, and Least Power. In
practice many applications violate these principles, and by virtue of their use of
URIs and the HTTP protocol, many of these applications would be in some sense
'on the Web.' However, these principles are normative insofar as they define what
could be considered as compliance with Web architecture, and so an application that
embodies them is compliant with Web architecture.

2.3.1 Principle of Universality

The Principle of Universality can be defined as any resource that can be identified
by a URI . The notion of both a resource and a URI was from their onset universal
in its ambition, as Berners-Lee said, “a common feature of almost all the data