There is, no doubt, a temptation to treat preventions, such as ‘the father’s grabbing the child prevented the accident’, and cases of ‘causation’ by omission, such as ‘the father’s inattention was the cause of the child’s accident’, as cases of genuine causation. I think they are not, and in this paper I defend a theory of what they are. More specifically, the counterfactual theory defended here is that a claim about prevention or ‘causation’ by omission should be understood not as (...) being directly about actual genuine causation but primarily as a counterfactual claim about genuine causation.1 The relation between actual causation and the mere possibility of causation allows my theory to explain both the difference and the similarity between the two notions (causation and prevention/omission). Further, the difference explains certain intuitions we have and the similarity justifies and explains the fact that for practical purposes we usually treat preventions and omissions as if they were genuine causation. Finally, the fact that this counterfactual theory of prevention and omission takes causation as primitive suggests that it is consistent with any theory of causation. This allows us to construct two arguments against what I will call genuinism, the view that cases of prevention and ‘causation’ by omission really are cases of genuine causation. In section II I show that genuinism does not account for the so-called intuition of difference. In section III I outline a number of problems that various theories of causation have with preventions and ‘causation’ by omission. These problems are ipso facto problems for genuinism, whereas I show in section V how the counterfactual theory solves those problems. Further, I answer a genuinist argument based on another type of intuition—the genuinist intuition—by showing why we have that intuition and how it should be handled (section VI). (shrink)