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SCIENCE 



[N. S. Vol. XXXIX. No. 993 



many readers that an apology and ex- 

 planation had to be published. What 

 then shall we say of the attempt to push 

 investigations into phenomena supposed 

 not to originate in the world of matter, but 

 in another world of whose existence we 

 have as yet little knowledge, to put it 

 mildly. Only that not only the general 

 public is profoundly interested in the mat- 

 ter, but that eminent scientists, including 

 astronomers, physicists and chemists of re- 

 nown, have thought such investigations 

 worth their attention, and have even de- 

 clared themselves to have obtained results 

 worthy of credence. 



But how far are we justified in going in 

 this direction? The objects of investiga- 

 tion in the physical sciences are manifold. 

 In many cases we can control the phe- 

 nomena to be observed, isolating them, from 

 disturbances, controlling the temperature, 

 pressure, and other elements, and making 

 the changes repeat at will. In other cases 

 we can exercise no control, and yet the 

 phenomena repeat themselves with periodic 

 regularity, and can be observed at pleasure, 

 as in the case of astronomical phenomena 

 or the tides. In other cases the phenomena 

 come at unknown times, irregularly, and 

 we can observe them only by being pre- 

 pared, as in the case of meteorological phe- 

 nomena and earthquakes. But in all these 

 cases there are definite phenomena, which 

 we agree do exist, and which affect matter 

 so as to be perceptible by instruments. But 

 when we. do not know whether phenomena 

 exist or not how shall we investigate them? 

 How easy it is for the layman to say, ' ' We 

 know that electromagnetic waves are trans- 

 mitted through the ether, which we can not 

 perceive by the senses, why should not waves 

 be emitted by the brain, and be similarly 

 transmitted through the ether 1 ' ' Why in- 

 deed! We may answer him that even if 

 we know nothing more of the ether than 



the speed of waves through it we know that 

 extremely well, and that whether or not we 

 know the mechanism of these waves (as I 

 conceive we do) we at least know their dif- 

 ferential equations, that is, the mode of their 

 transmission. Moreover we have many in- 

 struments which are affected by these 

 waves, whereas no one has ever managed, 

 by means of thought waves, to affect the 

 most sensitive instrument, whether torsion 

 balance, quartz fiber, electrometer or gal- 

 vanometer. When by taking thought, a 

 mind in this world or the next, shall pro- 

 duce the smallest deflection in an instru- 

 ment at a distance, then we shall be within 

 the means of physical investigation. But, 

 says the enthusiast, perhaps these waves, 

 being not of physical but of mental origin, 

 may be receivable not by physical, but only 

 by mental apparatus, and may work only 

 directly on the resonators of the brain. 

 Very well, let us begin with the phenomena 

 that we can control. It is easy to emit 

 brain waves, if such there be. The method 

 described above is then applicable. But if 

 we are in the region of seismic mental 

 waves, there is nothing to do but have our 

 mental resonators always in adjustment 

 and attuned. Then will come the difficulty 

 of discriminating between "strays" and 

 real receptions. How great this difficulty 

 is is shown by the almost vanishingly 

 small results of the societies for psychical 

 research, so-called, and by the delusions 

 from which reputable scientists have suf- 

 fered. We may here mention the investiga- 

 tions on the celebrated Eusapia Paladino, 

 who certainly secured good endorsements 

 in Europe, but when brought here and ex- 

 amined by a committee including psycholo- 

 gists, physicists, and other detectives, was 

 found to be explicable by purely physical 

 hypotheses. 



It is beyond my purpose to speak of the 

 relations of science to religion and theol- 



