Mind and Anti-Mind: Why Thinking Has No Functional Definition

Functionalism is perhaps the most prominent theory of mind today. The central thesis of functionalism is that the standard mental relations (or properties or states) are uniquely determined by their causal roles in functioning organisms. That is, the principles of psychology specify the characteristic way that (behavioral or physiological) input, the standard mental relations such as belief and desire, and (behavioral or physiological) output are causally arranged; and the central idea of functionalism is that, e.g., belief's characteristic causal role can be fulfilled by exactly one relation-namely, belief itself. Clearly, then, the most direct way to refute functionalism would be to show that there are relations that demonstrably differ from the standard mental relations and that, nevertheless, could fulfill the same causal role as those mental relations.     

Perceptual Categorization: Connectionist Modelling and Decision Rules

Although it is currently popular to model human associative learning using connectionist networks, the mechanism by which their output activations are converted to probabilities of response has received relatively little attention. Several possible models of this decision process are considered here, including a simple ratio rule, a simple difference rule, their exponential versions, and a winner-take-all network. Two categorization experiments that attempt to dissociate these models are reported. Analogues of the experiments were presented to a single-layer, feed-forward, delta-rule network. Only the exponential ratio rule and the winner-take-all architecture, acting on the networks' output activations that corresponded to responses available on test, were capable of fully predicting the mean response results. In addition, unlike the exponential ratio rule, the winner-take-all model has the potential to predict latencies. Further studies will be required to determine whether latencies produced under more stringent conditions conform to the model's predictions.