Steven Pinker -- How the Mind Works - Hampshire High Italian ...

Thinking Machines 121actor: action ; acted uponOr would it? Alas, it would not. Consider these thoughts:Baby same-as baby.Baby different-from slug.Slug different-from baby.Slug same-as slug.No set of connection weights that allow "baby" in the first slot and "sameas"in the middle to turn on "baby" in the third slot, and that allow "baby"and "different-from" to turn on "slug," and that allow "slug" and "differentfrom"to turn on "baby," will also allow "slug" and "same-as" to turn on"slug." It's the exclusive-or problem in a different guise. If the baby-to-babyand same-to-baby links are strong, they will turn on "baby" in response to"baby same-as " (which is good), but they will also turn on "baby" inresponse to "baby different-from " (which is bad) and in response to"slug same-as " (also bad). Jigger the weights all you want; you willnever find ones that work for all four sentences. Since any human canunderstand the four sentences without getting confused, the human mindmust represent propositions with something more sophisticated than a setof concept-to-concept or concept-to-role associations. The mind needs arepresentation for the proposition itself. In this example, the model needsan extra layer of units—most straightforwardly, a layer dedicated to representingthe entire proposition, separately from the concepts and theirpropositionooooooooooooo oooo oooooacted upon