LIFE IN SPACE AND TIME 23 



The intellectual elegance of the argument, here too 

 briefly sketched, demands admiration; the difficulties with 

 it He mainly in its premises. The main point at issue is the 

 geometrical character of the canal system, which is doubted 

 or denied by the majority of observers. It is hardly necessary 

 to say that no question as to the trustworthiness and 

 integrity of any of the distinguished observers who have 

 studied the planet can for a moment be raised; each faith- 

 fully describes what the subconscious processes of his 

 brain report to his consciousness. But, when these reports 

 diff'er so widely, with respect to details which all agree 

 are clearly seen only by ghmpses, there appears to be no 

 way to determine which, if any, of the drawings of various 

 observers most resembles what we would see if the planet 

 were ten times nearer, and its details observable with 

 certainty. 



Again, the progressive "quickening" of the canals need 

 not necessarily be due to the progress of water along them. 

 Lau has suggested that as the polar caps melt, the atmos- 

 phere may become foggy, and later clear up, beginning 

 in high latitudes. The growth of vegetation, which has 

 proceeded under the fog, would then first become visible 

 near the pole, and appear to progress toward the equator 

 as the fog cleared. This effect might advance northward 

 or southward in opposite seasons, without any water having 

 to run up-hill. Indeed, one of the chief difficulties of the 

 hypothesis of artificial irrigation is that the planet's whole 

 surface must be assumed to be extraordinarily flat. 



In view of these considerations, the verdict which must 

 at present be rendered upon Lowell's suggestion is the 

 Scottish one of '*not proven." There is too much uncertainty 

 about some of the more critical data, and too many alterna- 

 tive explanations, to justify acceptance. But to deny that 

 intelligent life exists on Mars would be quite unwarranted. 

 Even a direct proof that all the visible features of the 

 planet's surface were of "natural" (as distinguished from 

 artificial) origin would obviously be no evider ce at all for the 

 negative. 



The question must, in our present state of knowledge, 

 be left open, without prejudice. Animals, indeed, intelligent 



