October 3, 2021 – The advent of quantum mechanics in the 1920s brought with it the idea that fundamental physical processes may be stochastic which is to say random but constrained by probabilistic law. Rather than the future being determined in advance, as envisaged by Newtonian mechanics, one actual future is stochastically selected from a range of alternativepossibilities. A way to restore determinism to physics is to replace the idea of a stochastic process with that of a dendritic process where all (possible) outcomes actually occur, each in a different (branch) of a burgeoning quantum multiverse. The idea has been much discussed but remains very controversial. Paul explains some of the conceptual difficulties involved and how the idea may be linked to a non-standard materialist conception of the mind-body relation.

If you are constantly ‘splitting’ into every future previously thought merely possible, in what sense is it you who lives through those futures? An analysis of trans-temporal identity is required. How can the concept of probability apply to multiple coexistent futures rather than the selection of a single actual future from a range of alternative possiblities? A thought experiment involving hypothetical parallel universes helps. If ‘splitting’ is intelligible, what would the implications be for our choices in life if it came to be generally accepted by physicists and philosophers of physics?

Paul Tappeneden, PhD, teaches philosophy of science to physics students in Grenoble, France.

Length: 2 hours