But the evident fact of a present periodicity of imperfect form suggests another possible conception. We are under no necessity to regard the universe as finite either in space or time. On the contrary. We tend naturally to conceive of it as finite after the analogy of particular things which we perceive continually to arise and perish; but as concerns space, we have no knowledge of any limit, and, as concerns time, the conception of any actual beginning or end to the universe as a whole is only the ancient naive idea which science has disproved in showing that neither matter nor motion ever perish. An infinite universe is conceivable, in which not exactly the same but very similar forms, or forms of which the successive ones closely resemble each other though those widely separated may be very dissimilar, continue to arise and be destroyed to all eternity. The conception of a primal nebular mist is not a necessary inference from astronomic phenomena; it is as easy and as logical to regard the various phases of planetary development revealed to us by the telescope as so many phases of an evolution and dissolution continually recurring in different parts of the universe, one extreme of which is represented by the nebular mist, the other by the cold and lifeless remains of planets gradually suffering dissolution as they revolve through space. The greater the immensity of the universe is conceived to be, the nearer our conception of it must approach to this type. But the term Tendency to Stability is misapplied when applied to such infinite and imperfect periodicity--to the motion, thus conceived, of the universe as a whole.