Contemporary debates in philosophy of science

Speaker: Alasdair Richmond (University of Edinburgh)

Title: The Big Pitowsky: Doing Infinitely Many Tasks in (Less Than) No Time at All

Abstract: Suppose we want to determine the truth-value of Goldbach’s Conjecture by testing all even integers (> 2) to see if they are the sum of two primes. But we’re in a hurry – so much so in fact that we want the answer (ideally) before we’ve even asked the question. Could such negative-time supertasks be performed, and in what sort of spacetime? Causal pathologies in otherwise classical spacetimes not only allow hyper-Turing tasks otherwise only performable in Pitowsky or Malament-Hogarth spacetimes, they also allow ‘ultratasks’, i.e. supertasks where an observer can access an infinite sequence of operations in zero or negative proper time. This talk argues that accepting causal pathologies ("time travel") may be among the lesser revisions we need if we’re to have anything like working supertask machines.