“Here, indeed, we arrive at a barrier to our reasonings; since we can not know whether this condition is or is not fulfilled. If the ether which fills the interspaces of our Sidereal system has a limit somewhere beyond the outermost stars, then it is inferable that motion is not lost by radiation beyond this limit; and if so, the original degree of diffusion may be resumed. Or supposing the ethereal medium to have no such limit, yet, on the hypothesis of an unlimited space, containing, at certain intervals, Sidereal Systems like our own, it may be that the quantity of molecular motion radiated into the region occupied by our Sidereal System, is equal to that which our Sidereal System radiates; in which case the quantity of motion possessed by it, remaining undiminished, it may continue during unlimited time its alternate concentrations and diffusions. But if, on the other hand, throughout boundless space filled with ether, there exist no other Sidereal Systems subject to like changes, or if such other Sidereal Systems exist at more than a certain average distance from one another; then it seems an unavoidable conclusion that the quantity of motion possessed, must diminish by radiation; and that so, on each successive resumption of the nebulous form, the matter of our Sidereal System will occupy a less space; until it reaches either a state in which its concentrations and diffusions are relatively small, or a state of complete aggregation and rest. Since, however, we have no evidence showing the existence or non-existence of Sidereal Systems throughout remote space; and since, even had we such evidence, a legitimate conclusion could not be drawn from premises of which one element (unlimited space) is inconceivable; we must be forever without answer to this transcendent question.” (_First Principles_, § 182, pp. 535-6.) See, then, how the case stands. After urging against me the argument of “two eminent physicists” as fatal to my conclusions, he thereupon expresses dissent from the premises of that argument; and the reasons he gives for dissenting are like those given by me before he was out of his teens! * * * * *