Not propositions

Current computational accounts of meaning in the cognitive sciences are based on abstract, amodal symbols (e.g., nodes, links, propositions) that are arbitrarily related to their referents. We argue that such accounts lack convincing empirical support and that they do not provide a satisfactory account for linguistic meaning. One historic set of results supporting the abstract symbol view has come from investigation into comprehension of negated sentences, such as "The buttons are not black." These sentences are presumed to be understood as two propositions composed of abstract symbols. One proposition corresponds to "the buttons are black," and it is embedded in another proposition corresponding to "it is not true." Thus, the propositional account predicts (a) that comprehension of negated sentences should take longer than comprehension of the corresponding positive sentence (because of the time needed to construct the embedding), but (b) that the resulting embedded propositions are informationally equivalent (but of opposite valence) to the simple proposition underlying the positive sentence. Contrary to these predictions, Experiment 1 demonstrates that negated sentences out of context are interpreted as situationally ambiguous, that is, as conveying less specific information than positive sentences. Furthermore, Experiment 2 demonstrates that when negated sentences are used in an appropriate context, readers do not take longer to understand them. Thus, difficulty with negation is demonstrated to be an artifact of presentation out of context. After discussing other serious problems with the use of abstract symbols, we describe the Indexical Hypothesis. This embodied account of meaning does not depend on abstract symbols, and hence it provides a more satisfactory account of meaning.