Septembee 16, 1921] 



SCIENCE 



239 



other interested bodies, but of these, nine have 

 subsequently been abandoned. At least five 

 patents have been developed to such a stage 

 as to be ready for immediate industrial appli- 

 cation. 



It will be obvious from this short summary 

 of the activities of the department, based upon 

 information kindly supplied to me by Sir 

 Francis Ogilvie, that this great scheme of 

 state-aided research has been conceived and is 

 administered on broad and liberal lines. A 

 considerable number of valuable reports from 

 its various boards and committees have already 

 been published, and others are in the press, 

 but it is, of course, much too soon to appre- 

 ciate the full effects of their operations. But 

 it can hardly be doubted that they are bound 

 to exercise a profound influence upon indus- 

 tries which ultimately depend upon discovery 

 and invention. The establishment of the de- 

 partment marks an epoch in our history. Wo 

 such comprehensive organization for the ap- 

 plication of science to national needs has ever 

 been created by any other state. We may say 

 we owe it directly to the Great War. Even 

 from the evil of that great catastrophe there 

 is some soul of goodness would we observingly 

 distil it out. T. Edward Thorpe 



{To be concluded) 



LIFE IN OTHER WORLDS 



Does life — especially intelligent life — exist 

 elsewhere than on the earth? Three letters in 

 recent numbers of Science discuss this age- 

 old problem. And it is noticeable that, as 

 usual, the astronomers take the affirmative 

 and the biologists the negative side of the 

 argument. There may be two reasons for this. 



1. Astronomers, physicists, mathematicians, 

 are accustomed to hold a more receptive atti- 

 tude, an open mind, toward hypotheses that 

 can not be definitely disproved. This frame 

 of mind is natural and adapted to their work. 

 They are accustomed to deal with problems 

 which can be solved by mathematical and de- 

 ductive methods. A limited number of solu- 

 tions appear, all of them to be receptively 

 considered until they can be definitely dis- 

 proved. 



The biologist, on the other hand, deals with 

 a different sort of problem. His evidence is 

 almost always inductive, experimental. His 

 subjects are far too complex, too little under- 

 stood, to admit of mathematical analysis, save 

 in their simpler aspects. And always he is 

 compelled to adopt toward the illimitable num- 

 bers of possible explanations, a decidedly ex- 

 clusive attitude, and to leave out of considera- 

 tion all factors that have not something in the 

 way of positive evidence for their existence. 

 If he fails to do so, he soon finds himself 

 struggling hopelessly in a bog of unprofitable- 

 speculations. A critical rather than a recep- 

 tive frame of mind is the fundamental condi- 

 tion of progress in his work. 



2. The second reason is that the astronomer 

 or cosmologist has in mind when he thinks of 

 this problem, the physical and chemical con- 

 ditions that would render life possible. If 

 these be duplicated elsewhere he sees life as 

 possible, and by the incidence of the laws of 

 chance probable or almost certain, if they 

 be duplicated often enough. Viewing the 

 innumerable multitude of stars, each of them 

 a solar system with possible or probable plan- 

 ets analogous to our own, he sees such multi- 

 tudinous duplications of the physical condi- 

 tions that have made life possible on our 

 earth, that it appears to him incredible that 

 all stand empty and lifeless. 



The biologist, on the other hand, has at the 

 forefront of his mind the history and evolu- 

 tion of life on the earth. He knows that al- 

 though these conditions favoring the creation 

 of living matter have existed on earth for 

 many millions or hundreds of millions of 

 years, yet life has not come into existence on 

 earth save once, or at most half a dozen times, 

 during that time. The living beings on earth 

 are reducible at most to a few and probably 

 to one primary stock, all their present variety 

 being the result of the evolutionary processes 

 of differentiation and adaptation. It must 

 appear therefore to him that the real condi- 

 tions for the creation of life on earth have 

 involved, not merely the favoring physical 

 conditions, but some immensely complex con- 

 catenation of circumstances so rare that even 



