ioo SCIENCE PROGRESS 



on the map by a yard, a mile, a million miles, a million light- 

 years ! We cannot say that the universe is limited, because 

 such a statement is overwhelmingly beyond our present or 

 possible knowledge ; and if we cannot say that the universe is 

 limited, we cannot say that the energy of the universe is limited, 

 nor can we share Dr. Johnstone's surprise that the available 

 energy has not already all been dissipated. Indeed, one cannot 

 but feel that Dr. Johnstone does not appreciate the magnitude 

 of the factors with which he tries to operate. He affirms with 

 confidence that restoration of energy is the " only way out of 

 this deadlock." He forgets the other possible way out named 

 above : which, indeed, seems far more probable than his. But 

 even had I been unable to indicate another way out, it does not 

 follow that because you can only think of one solution, there- 

 fore that solution must be true. This is not sound reasoning in 

 any department of science : it is less sound than ever when 

 you are dealing with such incomprehensible doctrines as the 

 infinity of time and space, and similar intangible conceptions, 

 which we are bound by the limitations of our intellect to 

 believe, and yet are for ever incapable of understanding. 



Reverting to the above suggested star-map in which the 

 distance of the most remote of visible stars is represented by 

 the length of one inch, we may imagine that on the same scale 

 at a distance of a million miles there may be other bodies ; and 

 others again at a distance of a further million and so on ad 

 infinitum. Even were these bodies actually no larger than a pea, 

 and even were their temperatures not more than i° above the 

 average of our stellar universe, yet the total amount of energy 

 contained in them would be infinite, and they never in finite 

 time would lose any fraction of their excess of potential over 

 that of our universe. Energy, moreover, may be infinite not 

 only in extension, but in intension. The vast sources of energy 

 lately discovered within the atom may be paralleled by other 

 infinite stores within the electron. In short, Dr. Johnstone's 

 attempt to argue that the second law of thermodynamics cannot 

 a priori always hold good, fails absolutely : he cannot prove 

 any such doctrine by deduction, more especially by deductions 

 with such shadowy and metaphysical premises : he can prove 

 it, if at all, only by induction — by citing a case in which the 

 law is found to be in abeyance ; and he does not even hint at 

 any such case. 



