ON PEAYEE AS A FOEM OF PHYSICAL ENEEGY. 43 



takes pleasure in granting their requests. We know 

 also that this compliance extends to the alteration, 

 within certain limits, of the current of events on earth. 

 With this suggestion offered by experience, it is no de- 

 parture from scientific method to place behind natural 

 phenomena a Universal Father, who, in answer to the 

 prayers of His children, alters the currents of those 

 phenomena. Thus far Theology and Science go hand 

 in hand. The conception of an aether, for example, 

 trembling with the waves of light, is suggested by the 

 ordinary phenomena of wave-motion in water and in 

 air; and in like manner the conception of personal 

 volition in nature is suggested by the ordinary action 

 of man upon earth. I therefore urge no impossibilities, 

 though I am constantly charged with doing so. I do 

 not even urge inconsistency, but, on the contrary, frankly 

 admit that the theologian has as good a right to place 

 his conception at the root of phenomena as I have to 

 place mine. 



But without verification a theoretic conception is 

 a mere figment of the intellect, and I am sorry to find, 

 us parting company at this point. The region of theory, 

 both in science and theology, lies behind the world of 

 the senses, but the verification of theory occurs in the 

 sensible world. To check the theory we have simply 

 to compare the deductions from it with the facts of 

 observation. If the deductions be in accordance with 

 the facts, we accept the theory : if in opposition, the 

 theory is given up. A single experiment is frequently 

 devised, by which the theory must stand or fall. Of 

 this character was the determination of the velocity of 

 light in liquids, as a crucial test of the Emission 

 Theory. According to it, light travelled faster in 

 water than in air ; according to the Undulatory 

 Theory, it travelled faster in air than in water. An 

 33 



