Now, the assertion that the peculiarities which make the solar system stable and the earth habitable have flowed naturally and necessarily from the simple mutual gravity of the several parts of nebulous matter, is one which greatly requires proof, but which has never received it. In saying this, we do not challenge the proof of the nebular theory itself. That theory may or may not be true. We are quite willing to suppose it true; to grant that it has been scientifically established. What we maintain is, that even if we admit unreservedly that the earth, and the whole system to which it belongs, once existed in a nebulous state, from which they have been gradually evolved into their present condition conformably to physical laws, we are in no degree entitled to infer from the admission the conclusion which Comte and others have drawn. The man who fancies that the nebular theory implies that the law of gravitation, or any other physical law, has of itself determined the course of cosmical evolution, so that there is no need for believing in the existence and operation of a Divine Mind, proves merely that he is not exempt from reasoning very illogically. The solar system could only have been evolved out of its nebulous state into that which it now presents if the nebula possessed a certain size, mass, form, and constitution--if it was neither too rare nor too dense, neither too fluid nor too tenacious; if its atoms were all numbered, its elements all weighed, its constituents all disposed in due relation to each other--that is to say, only if the nebula was in reality as much a system of order, which intelligence alone could account for, as the worlds which have been developed from it. The origin of the nebula thus presents itself to the reason as a problem which demands solution no less than the origin of the planets. All the properties and laws of the nebula require to be accounted for. What origin are we to give them? It must be either reason or unreason. We may go back as far as we please, but at every step and stage of the regress we must find ourselves confronted with the same question--the same alternative.