Previous analyses on the gauge invariance of the action for a generally covariant system are generalized. It is shown that if the action principle is properly improved, there is as much gauge freedom at the endpoints for an arbitrary gauge system as there is for a system with “internal” gauge symmetries. The key point is to correctly identify the boundary conditions for the allowed histories an...

OSCAR is a fully implemented architecture for a cognitive agent, based largely on the author’s work in philosophy concerning epistemology and practical cognition. The seminal idea is that a generally intelligent agent must be able to function in an environment in which it is ignorant of most matters of fact. The architecture incorporates a general-purpose defeasible reasoner, built on top of an...

Modern uses of the word literally are surveyed, and the solecistic misuse of this word as an expression of speaker commitment is shown to be a natural semantic extension of its basic metalinguistic meaning. The development appears to be typical of a large class of intensifiers, though it is argued that literally itself is only in the early stages of such an evolution. Aspects of this developmen...

Many have pondered the potential impact of Mendel's work if Darwin had come across it in his lifetime. Darwin found difficulty with a blending inheritance and natural selection but a new letter suggests he was grappling with a more modern view. Nigel Williams reports.