 Counterfactual Suppositions Viewed Differently—Interventions: Invariance theories characterize the counterfactually supposed antecedent conditions under which a generalization remains stable differently than Lange’s stability theory. Lange simply assumes these conditions, e.g., the temperature of the gas is 32ºC, to be the result of counterfactual suppositions. We suppose that \(p\) is true and see whether the law \(l\) remains true supposing \(p\). So, stability theory is indifferent concerning how the supposed state of affairs comes about. Invariance theory is more restrictive in characterizing the counterfactual situations: A counterfactual situation refers to a change in the value of a variable. For an invariance theorist, it is important to explain how the change of a variable is brought about: the change of the value of a variable must be the causal outcome of an intervention. An intervention consists in a local change that sets a variable \(X\) to a certain value and at the same time decouples \(X\) from all \(X\)-independent variables, as explained in section 3. So, an intervention on \(X\) is a direct, exogenous causal influence on some variable \(X\) which (1) does only act on \(X\) itself while (2) other variables \((Z)\) are only changed in virtue of being directly or indirectly caused by the change in \(X\). Notice that interventions need not be carried out by human beings. Instead they are conceived as hypothetical (not necessarily human) causes. (cf. Woodward 2003, 98; and Woodward 2003, 103f., 123–127 for arguments against an anthropomorphic interpretation of interventions.) 