If, next, our inquirer should go farther in his investigations of the solar system, and endeavor to satisfy himself concerning the mode in which the different bodies of this system came into existence in their respective positions, the history of astronomy would teach him that there has been a theory on this subject which fails to account for the existence of this system of bodies without the hypothesis of some special creation. This theory is what is called the nebular hypothesis. It supposes that the solar system was evolved out of a mass of fiery vapor, which filled the stellar spaces, and which became the bodies now observable by the telescope, and that they were finally swung into their respective places by the operation of the fixed laws of motion. But all that astronomers now undertake to say is that this hypothesis is a probably true account of the origin of the solar system, and not that it is an established scientific fact, or a fact supported by such proofs as those which show the existence of the laws of motion. The history of the nebular hypothesis, from the time of its first suggestion to the present day, shows that there are no satisfactory means of accounting for the method in which the supposed mass of fiery vapor became separated, consolidated, and formed into different bodies, and those bodies became ranged and located in their respective positions. The hypothesis that these results were all produced by fixed laws working upon a mass of fiery vapor, is one that has been reasoned out in very different ways; and this diversity of views is such that astronomers of the higher order do not undertake to say that opinions may not reasonably differ in regard to the principal question, namely, the question between the nebular hypothesis and the hypothesis of a special act or acts of creation.