Conferences on philosophy have much in common with academic conferences on anything else. But in one way they differ. Amongst philosophers, a lecture often matters less than what follows — ‘Q&A’, the question-and-answer period. That is when the speaker’s arguments and conclusions are put to the test.

Questioners propose counterexamples, allege fallacies, discern ambiguities. In response, the speaker fights for the life of their cherished ideas. Exchanges continue, back and forth, over several turns. The rest of the audience watches and listens keenly, as if following a chess match, trying to work out who’s winning. 

Sometimes a draw is offered with the words “It’s a stand-off” and tacitly accepted; sometimes the chair intervenes to cut short a stalemate. There is a code of signals to the chair: a raised hand means a new question, a raised finger a follow-up on the current point. A serious conference may schedule an hour for Q&A after each talk.