Knowledge representation: Two kinds of emergence

Two different but closely related issues in current cognitive science will be considered in this essay. One is the controversial and extensively discu ssed question of how connectionist and symbolic representations of knowledg e are related to each other. The other concerns the notion of connectionist learning and its relevance for the understanding of the distinction betwee n propositional and nonpropositional knowledge. More specifically, I shall give an overview of a result in Rantala and Vaden (1994) establishing a lim iting case correspondence between symbolic and connectionist representation s and, on the other hand, study the problem, preliminarily investigated in Rantala (1998), of how propositional knowledge may arise from nonpropositio nal knowledge. I shall also try to point out that on some more or less plau sible assumptions, often made by cognitive scientists, these results may ha ve some significance when we try to comprehend the nature of human knowledg e representation. Some of these assumptions are rather hypothethical and de batable for the time being and they will become justified in the future onl y if there will be more progress in the empirical and theoretical research on the brain and on artificial networks. The assumptions concern, besides s ome questions of the behavior of neural networks, such things as the releva nce of pattern recognition for modelling human cognition, in particular, kn owledge acquisition, and the relation between emergence and reduction.