152.] At the stage, where substance, as absolute power, is the self-relating power (itself a merely inner possibility) which thus determines itself to accidentality,--from which power the externality it thereby creates is distinguished--necessity is a correlation strictly so called, just as in the first form of necessity, it is substance. This is the correlation of Causality. (b) _Relationship of Causality._ 153.] Substance is Cause, in so far as substance reflects into self as against its passage into accidentality and so stands as the _primary_ fact, but again no less suspends this reflection-into-self (its bare possibility), lays itself down as the negative of itself, and thus produces an Effect, an actuality, which, though so far only assumed as a sequence, is through the process that effectuates it at the same time necessary. As primary fact, the cause is qualified as having absolute independence and a subsistence maintained in face of the effect: but in the necessity, whose identity constitutes that primariness itself, it is wholly passed into the effect. So far again as we can speak of a definite content, there is no content in the effect that is not in the cause. That identity in fact is the absolute content itself: but it is no less also the form-characteristic. The primariness of the cause is suspended in the effect in which the cause makes itself a dependent being. The cause however does not for that reason vanish and leave the effect to be alone actual. For this dependency is in like manner directly suspended, and is rather the reflection of the cause in itself, its primariness: in short, it is in the effect that the cause first becomes actual and a cause. The cause consequently is in its full truth _causa sui._--Jacobi, sticking to the partial conception of mediation (in his Letters on Spinoza, second edit. p. 416), has treated the _causa sui_ (and the _effectus sui_ is the same), which is the absolute truth of the cause, as a mere formalism. He has also made the remark that God ought to be defined not as the ground of things, but essentially as cause. A more thorough consideration of the nature of cause would have shown that Jacobi did not by this means gain what he intended. Even in the finite cause and its conception we can see this identity between cause and effect in point of content. The rain (the cause) and the wet (the effect) are the self-same existing water. In point of form the cause (rain) is dissipated or lost in the effect (wet): but in that case the result can no longer be described as effect; for without the cause it is nothing, and we should have only the unrelated wet left.