This article deploys the contrastive theory of causation to deal with three problems of the hypothetical thinking in omissive casual judgements: omission as causal relata, the proliferation of causes, and causal selection. It argues: first, claims about omissions are contrastive judgements; second, the hypothetical thinking in omissive causal judgements is constrained by norms and is counterfactual reasoning in a normalized situation; third, causal selection involves the application of norms. Finally, the point of causal selection in omissive causal judgments is to pick out appropriate targets for interventions, and this article proposes a criterion based on the cheapest cost preventer to supplement the norm-based criteria for causal selection.