2991. The representation of spiritual things by natural, and the correspondence of natural things with spiritual, may also be known from the consideration that what is natural cannot in any sense come into being without a cause prior to itself. Its cause exists in that which is spiritual. Nothing natural exists which does not have its cause there. Natural forms are effects and cannot appear as causes, let alone as the causes of causes, or first origins. Instead they take the forms they do from the use they perform in the place where they belong. Nevertheless the forms taken by effects represent the things that exist among causes, and these causes in turn represent those that exist among first origins. Thus all natural things represent those that exist among the spiritual things to which they correspond, and those spiritual things in turn represent those that exist among the celestial things in which they have their origin.