Whether space-time exists should neither be controversial nor even conceptually challenging, given the definitions of “space-time,” “events” and “instants.” The idea that space-time exists is no more ...

Re “Reprisals Go Around, and May Come Around” (news analysis, front page, Sept. 30): Conservatives are said to warn of the possibility that a future Democratic president might use the actions of our ...

The phenomenon of hearing voices inside the head, which others cannot, can be categorized as a common form of auditory hallucination. Hallucination is the perception or sensation of voices that can be ...