3. The theory of the formation of the Earth by the condensation of cosmic matter is that which now prevails in science as being that which is best justified by observation, which solves the greatest number of difficulties, and which leans more than all others upon the grand principle of universal unity. It is that which has been previously described in chap. VII, “General Uranography.”
The two theories, as we perceive, lead to the same result, - the primitive state of incandescence of the globe ceasing, the formation of a solid crust, the existence of the central fire, and the appearance of organic life as soon as the temperature renders it possible. They differ in the mode of formation of the Earth; and it is probable that, if Buffon had lived in our day, he would have had other ideas.
Geology takes the Earth at the point where direct observation is possible. Its state anterior to this can be only conjectural. Now, between two hypothesis, good sense teaches that it is necessary to choose the one sanctioned by logic, and which best agrees with observed facts.