This chapter focuses specifically on the notion of causation. Unless a causal interpretation can be given of quantum mechanics, there is a fundamental discontinuity between the quantum realm and everything else in the world. The quantum-theoretical dualism of waves and particles makes the same entity appear both as matter and as force. There are of course challenges to other basic ontological categories that come from quantum physics, such as to notions of continuity and identity. Both in philosophy and physics, there is a frequent assumption that causation is the provider or vehicle of determinism, via causal necessitation. The indeterminism of quantum physics leaves people with a more practical concern about causation. A feature of causation that makes predictions fallible is that causal processes are extremely sensitive to a change in context. The genuine interaction of multiple factors should therefore be seen as a symptom of causation rather than as something that needs to be analysed away by theoretical abstraction.