This article discusses Evidence-Based Practice (EBP) in the social sciences. After a brief outline of the discussion, the work of William Herbert Dray (1921-2009) is examined. Dray, partly following Collingwood, worked on different forms of causality and methodology in historical explanation (in comparison to the social sciences), based on a distinction between causes and reasons. Dray's ladder of rational understanding is also explored here. Taking his argumentation further and sometimes turning it upside-down, a scale of forms of causality is developed with accompanying types of interventions and possibilities for scientific proof of their effectivity. This scale makes it possible to weigh interventions regarding the degree to which "hard" scientific proof is possible for them. The article concludes with a brief discussion of how interventions in psychology and education should be chosen and can be justified, both those that do and those that don't lend themselves to empirical research.