This is the idea of simple self-subsisting intelligence . Reason does this in order to represent all determinations as existing in a single subject. The simplicity of substance is intended to be only the schema of this regulative principle and is not presupposed as being the actual ground of the properties of the soul. Nothing but advantage can result from the psychological idea thus conceived. The second regulative idea is the concept of the world in general.
Nature is the only given object in regard to which reason requires regulative principles.
In explaining appearances, we ought to treat the series of conditions in nature as if it were in itself infinite, that is, as if it proceeded in indefinitum . The third regulative idea is the idea of God. The idea of such a being seeks only to formulate the command of reason, that all connection in the world be viewed as if all such connection had its source in a single all-embracing being. Reason prescribes its own formal rule for the extension of its empirical employment, but not any extension beyond all limits of empirical employment. The first error that arises from using these ideas as constitutive is ignava ratio which is when we regard our investigation into nature as absolutely complete.