Unclear Distinctions Lead to Unnecessary Shortcomings: Examining the Rule Versus Fact, Role versus Filler, and Type Versus Predicate Distinctions from a Connectionist Representation and Reasoning Perspective

Book One

Volume

Proceedings of the AAAI Conference on Artificial Intelligence, 12

Neural Networks

This paper deals with three distinctions pertaining to knowledge representation, namely, the rules vs facts distinction, roles vs fillers distinction, and predicates vs types distinction. Though these distinctions may indeed have some intuitive appeal, the exact natures of these distinctions are not entirely clear. This paper discusses some of the problems that arise when one accords these distinctions a prominent status in a connectionist system by choosing the representational structures so as to reflect these distinctions. The example we will look at in this paper is the connectionist reasoning system developed by Ajjanagadde and Shastri. Their system performs an interesting class of inferences using activation synchrony to represent dynamic bindings. The rule/fact, role/filler, type/predicate distinctions figure predominantly in the way knowledge is encoded in their system. We will discuss some significant shortcomings this leads to. Then, we will propose a much more uniform scheme for representing knowledge. The resulting system enjoys some significant advantages over Ajjanagadde and Shastri’s system, while retaining the idea of using synchrony to represent bindings.