Published online by Cambridge University Press: 01 January 2022
A primary goal of quantum computer science is to find an explanation for the fact that quantum computers are more powerful than classical computers. In this paper I argue that to answer this question is to compare algorithmic processes of various kinds and to describe the possibility spaces associated with these processes. By doing this, we explain how it is possible for one process to outperform its rival. Further, in this and similar examples little is gained in subsequently asking a how-actually question. Once one has explained how-possibly, there is little left to do.
Thanks are due to Wayne Myrvold, Armond Duwell, Alan Love, Seamus Bradley, Sebastian Lutz, Lorenzo Casini, and my audience at the 2014 meeting of the Philosophy of Science Association. All of your comments were helpful to me in preparing this final version. Thanks also to the Alexander von Humboldt Foundation, whose financial support has made this project possible.