Research Projects

Under Review

A paper on the metaphysics of divergence and overlap in the Many Worlds Interpretation of quantum mechanics.

In Progress

"Unlucky Branches: (Dis)confirmation in Many Worlds"

The many worlds interpretation of quantum mechanics (MWI) entails the existence of unlucky branches: parts of the Everettian universe in which the relative frequencies of experimental outcomes differ from those that standard quantum mechanics would have us expect. Agents in such branches are ``unlucky” in that, while the MWI is true for these agents (if the MWI is in fact true), standard accounts of statistical inference demand that such agents would be irrational to accept the truth of the MWI. The fact that a multiplicity of outcomes determinately (and deterministically) take place, even those that standard quantum mechanics would take to be exceedingly unlikely, has led many to challenge whether the MWI is epistemically evaluable in the way that other scientific theories tend to be. I consider a puzzle that unlucky branches pose for rational observers with respect to scientific inference, theory choice, and (dis)confirmation from experimental data.

I argue that in order for the MWI to be susceptible to ordinary scientific inference, one must give up a common motivation for Humeanism about laws of nature: that laws can be known through observation of occurrent matters of fact. I then demonstrate that while views in which the universe is spatiotemporally infinite may also entail unlucky agents, the MWI is unique in that its low-weight branches are ineliminable parts of the overall Everettian mosaic: their existence is required for a complete Everettian universe, since the entire quantum state is incomplete without its low-weight parts.

"Overlap in EQM"

I defend the overlap view from several arguments posed in the literature. I first consider an argument from Tappenden (2008) that the overlap view cannot secure indexical reference in the present tense. I then examine arguments from Wilson (2011, 2013) that the overlap view cannot account for the truth-values of some future-oriented statements. The third concern I consider is that the overlap theorist cannot give a coherent explanation of subjective uncertainty in an Everettian multiverse. I show that these problems posed for the Everettian overlap view are not unique to EQM: self-locating uncertainty, the semantics of future-directed indexical sentences, and the theory of indexical reference present the same puzzles whether multiplicity arises from Everettian branching or analogous non-quantum cases of fission explored in the metaphysics and personal identity literature. So insofar as we have adequate solutions to these puzzles in non-Everettian contexts, those solutions should extend to EQM.

Given the plausibility that fission cases occur in non-Everettian contexts—e.g., through Parfittian teleporters, lab-grown duplicate humans (e.g., in the film Mickey 17 ) or mind-uploading (see Chalmers (2014))—it is pertinent to have metaphysics of identity, a semantics, and an account of subjective uncertainty that can accommodate overlapping agents irrespective of issues involving EQM.