Science used to be 'natural philosophy'; but Francis Bacon and the scientific revolution of the 16th and 17th centuries saw a parting of ways. Many scientists now consider philosophy to be largely irrelevant; while many philosophers consider science – particularly theoretical physics – to have lost its grip on reality. Exactly where, they ask, are all those ‘parallel universes’? It’s time for scientists and philosophers to get together and have a long chat…Tibor Molnar explores some of the issues they need to chat about. A Sydney Ideas and Department of Philosophy event held on 17 August 2017 as part of Sydney Science Festival for National Science Week: http://sydney.edu.au/sydney_ideas/lectures/2017/sydney_science_festival_2017_tibor_molnar.shtml