AS TO THE RELATIONS OP SCIENCE AND FAITH. 225 



wide toleration, and the best proof that tins is really not 

 injurious to Christianity. Science cannot afford to walk 

 ill fetters, and an attempt to bind it must always have the 

 effect of confining- its prizes to the rebellions.* 



9. The error of the ''evil tendency'' objection would merit 

 a long discussion. Men brand unwelcome doctrines as 

 having an evil tendency, when they see no direct answer 

 to them. Our reply is that we cannot satisfactorily estimate 

 tendencies; that persons holding chfterent tenets are often 

 alike distinguished for morality ; that the real question as to 

 the truth is one of testimony ; if the evidence is sufficient we 

 Avill receive the docti'ine, and leave the tendency to take care 

 of itself. In science, as in religion, we can only take what 

 comes to us, without asking whether it is likely to prove 

 beneficial or otherwise to faith. But the Christian scientist 

 enjoys his rehgion in every step of his work, and its influence 

 tends to confirm, not to weaken, his faith. 



10. It is sometimes an error to condemn a book because 

 you do not accept its conclusions. If it shows honest re- 

 search, it may be valuable and deserving of honour, thougli 

 the author failed hi the last stage. Such was Newton's work 

 on light, already referred to, which served for generations 

 as a scaffold for building up the science of optics. One of 

 its prophecies Avas that we should find light to pass more 

 rapidly through water than air; the fulfilment of this 

 prophecy in the opposite sense, by Foncault in 1850, gave 

 the coup de grace to the Newtonian theory, and established 

 the wave-theory. Dollond committed a blessed blunder 

 when he entered on a mathematical tournament against 

 Euler, maintaining that a lens composed of differing 

 materials, as glass and water, could never be cleared of 

 its dispersive colours. He afterwards improved on his own 

 work, when by reducing his arguments to experiment, he 

 surprised and refuted himself, and established Euler's 

 principle. Thus he became the fortunate inventor, and 

 his son the manufacturer, of achromatic lenses, as the sequel 

 of his antecedent error. 



11. A mischievous error bears on the relation of Divine 

 Providence to Physical Causation. Able men have supposed 



* Our freedom in Princeton from any religious-scientific difficulty is 

 chiefly due to the happy combination of intellectual independence and 

 Christian sympathy, which characterized the late President McCosh, and 

 which he ei^couratfed in others. 



