It is a possible conjecture, at first, that there may be other Worlds, having, as this has, their moral and intellectual attributes, and their relations to the Creator. It is also a possible conjecture, that this World, having such attributes, and such relations, may, on that account, be necessarily unique and incapable of repetition, peculiar, and spiritually central. These two opposite possibilities may be placed, at first, front to front, as balancing each other. We must then weigh such evidence and such analogies as we can find on the one side or on the other. We see much in the intellectual and moral nature of man, and in his history, to confirm the opinion that the human race is thus unique, peculiar and central. In the views which Religion presents, we find much more, tending the same way, and involving the opposite supposition in great difficulties. We find, in our knowledge of what we ourselves are, reasons to believe that if there be, in any other planet, intellectual and moral beings, they must not only be _like_ men, but must _be_ men, in all the attributes which we can conceive as belonging to such beings. And yet to suppose other groups of the human species, in other parts of the universe, must be allowed to be a very bold hypothesis, to be justified only by some positive evidence in its favor. When from these views, drawn from the attributes and relations of man, we turn to the evidence drawn from physical conditions, we find very strong reason to believe that, so far as the Solar System is concerned, the Earth _is_, with regard to the conditions of life, in a peculiar and central position; so that the conditions of any life approaching at all to human life, exist on the Earth alone. As to other systems which may circle other suns, the possibility of their being inhabited by men, remains, as at first, a mere conjecture, without any trace of confirmatory evidence. It was suggested at first by the supposed analogy of other stars to our sun; but this analogy has not been verified in any instance; and has been, we conceive, shown in many cases, to vanish altogether. And that there may be such a plan of creation,--one in which the moral and intelligent race of man is the climax and central point to which innumerable races of mere unintelligent species tend,--we have the most striking evidence, in the history of our own earth, as disclosed by geology. We are left, therefore, with nothing to cling to, on one side, but the bare possibility that some of the stars are the centres of systems like the Solar System;--an opinion founded upon the single fact, shown to be highly ambiguous, of those stars being self-luminous; and to this possibility, we oppose all the considerations, flowing from moral, historical, and religious views, which represent the human race as unique and peculiar. The force of these considerations will, of course, be different in different minds, according to the importance