Mystery Number Four - Computational Linguistics and Talking Robots - page 75

newly added inference is automatically connected. These bidirectional con-
nections between inferences may be implemented efficiently by pointers.
Which inferences are activated at any given moment is determined by the
agent's current state: recognition and inferencing produce a continuous stream
of proplets, which are screened and used to select corresponding content in the
Word Bank (subactivation, Sect. 5.4). This may apply at any level of abstrac-
tion and to any choice of domain. The extent of the subactivation is determined
by such parameters as the available computing power, and the agent's personal
interests and preferences.
High abstraction level patterns are used to select and subactivate (Sect. 5.4)
relevant areas of content (domains). Intersection results in a substantially re-
duced set of proplets (search space reduction). Nevertheless, the result may
still be a large number of inferences, each complete with corresponding con-
tents and a next step for action. The triple consisting of (i) all contents trigger-
ing the antecedent, (ii) the inference, and (iii) the action blueprint derived by
the consequent is called a tia triple (for trigger, inference, action).
The set of tia triples is evaluated in a cost-benefit manner, which results
in further data reduction, i.e., a manageable number of blueprints for action.
Which action is selected to be realized may often be a matter of random choice,
especially when time is of essence. But it may also be the choice of long-term
planning. Technically, the final step is a switch from the subjunctive mood to
the indicative mood (Sect. 5.6), resulting in external action (realization).
The following example shows an inference chain (rule level) interacting with
the Word Bank (content level). In line with SIP, the consequent of proposition
n serves as the antecedent of proposition n+1 .

5.2.5 N EW CONTENT DERIVED BY THE INFERENCE CHAIN 5.2.1

β β

rule level: be hungry K cm eat food K+1 pre

Word Bank: moi be hungry 211 moi eat food 212

β β

get α get (food K+1) K+2 down K+3 exec

moi get (food 212) 213 moi get apple 214

β α

at γ

β

take α locate K+4 exec K+5 exec

moi locate (apple 214) at cupboard 215 moi take (apple 214) 216

β α β

(eat K+1) K+6 up (eat K+1) (food K+1) K+7

moi (eat 212) (apple 214) 217 moi (eat 212) (food 212) 218

The four double lines should be read as one, i.e., as
rule level: p1 cm p2 pre p3 down p4 exec p5 exec p6 exec p7 up p8
Word Bank: q1 q2 q3 q4 q5 q6 q7 q8 .