Mystery Number Four - Computational Linguistics and Talking Robots - page 70

the content-addressable memory of a Word Bank (Sect. 4.1) have in common
that they are being browsed by a cognitive agent. It is just that in a private
library the browsing agent is located inside the arrangement of topics on their
shelves, while the proplets in a Word Bank are located inside the cognitive
agent. As a consequence, the role of the browsing user in a private library
seems to be unfilled in a Word Bank.
DBS fills this role, however, with a focus which is like a point of light navi-
gating from one proplet to the next. Unlike with the browsing user in a private
library, the control is not located in the focus. Instead, the motion of the fo-
cus is controlled in part by the semantic relations between the proplets, which
are used like a railroad system for the navigation. 2 The other part is provided
by LA-think rules and inferences which relate the agent's current situation to
precedents in memory and derive new content serving as blueprints for actions
to maintain the agent in a state of balance.
Putting it metaphorically, the navigation of the focus through the railroad
system of connected proplets resembles a pinball machine (cf. L&I'10), with
the focus serving as the ball and the slanted playing field with its springs and
levers serving as the railroad system. Because cognitive operations are agent-
internal, there is no “retrieval” in the usual sense. Instead, the navigation of
the focus merely visits successor proplets - as an activation which may be
visualized as lighting up the proplets traversed, with an afterglow of suitable
duration and rate of decay (annealing).
The goal of maintaining the agent in a state of balance provides a compu-
tational reconstruction of intention , just as the agent's recognition and action
procedures provide a computational reconstruction of concepts ,whichDBS
reuses as the meanings of language. This differs from Grice (1957, 1965,
1969), who uses an undefined notion of intention to define natural language
meaning:
5.1.1 D EFINITION OF MEANING BY G RICE
Definiendum: U meant something by uttering x.
Definiens: For some audience A, U intends his utterance of x to produce in A some effect
(response) E, by means of A's recognition of the intention.
This charming definition uses “intends” and “recognition of the intention” in
the definiens as intuitive notions which do not contribute to a computational
2 Thus, just as the core value of a proplet serves the double function of (i) representing the lexical
semantics and (ii) determining the location for storage and retrieval, its continuation values serve the
double function of (i) representing the compositional semantics and (ii) establishing a railroad system
for the focus navigation, providing each proplet with only a limited choice of successor proplets.