Abstract
In this paper we defend the view that mechanisms are underpinned by networks of
difference-making relations. First, we distinguish and criticise two different kinds of arguments
in favour of an activity-based understanding of mechanism: Glennan’s metaphysics-
first approach and Illari and Williamson’s science-first approach. Second, we
present an alternative difference-making view of mechanism and illustrate it by looking at
the history of the case of scurvy prevention. We use the case of scurvy to argue that evidence
for a mechanism just is evidence for difference-making relations.