 It turns out that the science of quantum computation is able to illuminate this debate. Cuffaro (2015) argues that when one examines the question of the source of quantum “speed-up”, one sees that to answer this question is to compare algorithmic processes of various kinds, and in so doing to describe the possibility spaces associated with these processes. By doing so one explains how it is possible for one process to outperform its rival. Further, Cuffaro argues that in examples like this, once one has answered the how-possibly question, nothing is actually gained by subsequently asking a how-actually question.