 (3) Sturm’s account of passive forms breaks with the idea that explanatory principles in natural philosophy must also account for the active power that brings phenomena about. In this sense, Sturm dismisses the idea that causal explanations must be based on active powers intrinsic to the natural agents themselves. According to Sturm, all phenomena are brought about by God himself. But God’s power being indifferent, differences among phenomena depend on passive forms, which operate as sine quibus non conditions for their production. This means that the explanandum in natural phenomena is not the fact that something is brought about, but rather the specific characteristics of what is brought about. God’s power explains that something (in general) is brought about, but only passive forms explain what is brought about in particular and how. The explanandum in natural phenomena is thus the specificity of the phenomenon at stake, and the explanans of this phenomenon are passive forms, which are a matter of empirical investigation.