20. Perhaps again, it may be said, that in speaking of the shortness of the time during which man has occupied the earth, in comparison with the previous ages of irrational life, and of blank matter, we are taking man at his present period of existence on the earth:--that we do not know that the race may not be destined to continue upon the earth for as many ages as preceded the creation of man. And to this we reply, that in reasoning, as we must do, at the present period, we can only proceed upon that which has happened up to the present period. If we do not know how long man will continue to inhabit the earth, we cannot reason as if we did know that he will inhabit it longer than any other species has done. We may not dwell upon a mere possibility, which, it is assumed, may at some indefinitely future period, alter the aspect of the facts now before us. For it would be as easy to assume possibilities which may come hereafter to alter the aspect of the facts, in favor of the one side, as of the other.[4] What the future destinies of our race, and of the earth, may be, is a subject which is, for us, shrouded in deep darkness. It would be very rash to assume that they will be such as to alter the impression derived from what we now know, and to alter it in a certain preconceived manner. But yet it is natural to form conjectures on this subject; and perhaps we may be allowed to consider for a moment what kind of conjectures the existing stage of our knowledge suggests, when we allow ourselves the license of conjecturing. The next Chapter contains some remarks bearing upon such conjectures. FOOTNOTES: [1] Among the most recent expositors of this doctrine we may place M. Henri Martin, whose _Philosophie Spiritualiste de la Nature_ is full of striking views of the universe in its relation to God. (Paris. 1849.) [2] Most readers who have given any attention to speculations of this kind, will recollect Newton's remarkable expressions concerning the Deity: "Æternus est et infinitus, omnipotens et omnisciens; id est, durat ab æterno in æternum, et adest ab infinito in infinitum.... Non est æternitas et infinitas, sed æternus et infinitus; non est duratio et spatium, sed durat et adest. Durat semper et adest ubique, et existendo semper et ubique durationem et spatium constituit."