 If interventionism is formulated as above, this criticism seems misplaced. The interventionist account does not hold that causal concepts apply or make sense only when the appropriate interventions can actually be carried out. Nor does it deny that there are other ways of testing causal claims besides carrying out interventions. Instead, interventionism holds that causal claims apply or have truth values whenever the appropriate counterfactuals concerning what would happen if interventions were to be performed have truth values. As explained above, interventionists think that sometimes such counterfactuals are true even if the interventions in question cannot actually be performed. Similarly, interventionists can readily agree that causal claims may be tested and confirmed by, for example, purely observational data, not involving interventions or manipulations—their view, though, is that what is confirmed in this way is a claim about what would happen if certain interventions were to be performed. In fact, thinking of causal claims in this way helps to clarify why certain strategies for causal inference with observational data, such as the use of instrumental variables, are more likely to lead to reliable conclusions than alternatives (Woodward 2015). 