“One stable homogeneity only, is hypothetically possible. If centers of force, absolutely uniform in their powers, were diffused with absolute uniformity through unlimited space, they would remain in equilibrium. This, however, though a verbally intelligible supposition, is one that can not be represented in thought; since unlimited space is inconceivable.”
So that this nominal exception which Professor Ward urges against me as a “fatal defect,” was set forth by me thirty-seven years ago!
A somewhat more involved case may next be dealt with. Professor Ward writes:—
“Moreover, on the physical assumption from which Mr. Spencer sets out, viz., that the mass of the universe and the energy of the universe are fixed in quantity—which ought to mean are finite in quantity—there can be no such alternations [of evolution and dissolution] as he supposes” (i., 192).
After some two pages of argument, he goes on:—
“And so while all transformations of energy lead directly or indirectly to transformation into heat, from that transformation there is no complete return, and, therefore finally no return at all. This then is the conclusion to which Mr. Spencer’s premises lead. Two eminent physicists who accept those premises may be cited at this point: ‘It is absolutely certain,’ they say, ‘that life, so far as it is physical, depends essentially upon transformations of energy; it is also absolutely certain that age after age the possibility of such transformations is becoming less and less; and, so far as we yet know, the final state of the present universe must be an aggregation (into one mass) of all the matter it contains, i. e. the potential energy gone, and a practically useless state of kinetic energy, i. e. uniform temperature throughout that mass.... The present visible universe began in time and will in time come to an end’” (p. 194).
Mark now, however, that this opinion of “two eminent physicists,” quoted to disprove my position, and tacitly assumed to have validity in so far as it serves that end, is forthwith dismissed as having, for other purposes, no validity. His next paragraph runs:—
“To this conclusion we are surely led from such premises. But again I ask what warrant is there for the premises? Our experience certainly does not embrace the totality of things, is, in fact, ridiculously far from it. We have no evidence of definite space or time limits; quite the contrary. Every advance of knowledge only opens up new vistas into a remoter past and discloses further depths of immensity teeming with worlds.”
Thus the truth urged against me is that we can not know anything about these ultimate physical principles in their application to the ultra-visible universe. But, unhappily for Professor Ward’s criticism, I entered this same caveat long ago. Demurring to that doctrine of the dissipation of energy to which he now demurs, I wrote:—
“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.)