The claim that in principle psychology is restricted to establishing weak equivalence . Weak equivalence is equivalence with respect to input/output behaviour. Therefore, measuring behavioural data is unable to establish equivalence at the level of functional architecture . Behavioural studies are indeterminate with respect to strong equivalence.
This issue is of importance to cognitive psychology because, if true, it implies that cognitive psychology cannot generate insight into cognition without importing knowledge based on non-behavioural observations from other disciplines.
Pylyshyn, Z. W., "Computing in cognitive science", in Posner, M.I. (ed.) 1989, Foundations of Cognitive Science, MIT Press, Cambridge MA.
Contributed by J. Andrews, November 23, 1995