152 A Century of Science 



and from year to year, in more ways than we can 

 detect or enumerate. It opens our minds to some 

 notions, and makes them incurably hostile to others ; 

 so that, for example, new truths well-nigh beyond 

 comprehension, like some of those connected with 

 the luminiferous ether, are accepted, and old be 

 liefs once universal, like witchcraft, are scornfully 

 rejected. Vast changes in mental attitude are thus 

 wrought before it is generally realized. Into the 

 new scheme of things old beliefs no longer fit, and 

 are therefore thrown aside and forgotten. Now 

 our orthodoxies are of older date than the goodly 

 fabric of modern knowledge. They are the out 

 come of more primitive and childlike thinking, they 

 have ceased to fit the world as we know it, and 

 therefore they fade and fall away from us, in spite 

 of all our efforts to retain undisturbed the venera 

 ble and hallowed associations. In this inevitable 

 struggle there has always been more or less pain, 

 and hence free thought has not usually been popu 

 lar. It has come to our life feast as a guest un 

 bidden and unwelcome ; but it has come to stay 

 with us, and already proves more genial than was 

 expected. Deadening, cramping finality has lost 

 its charm for him who has tasted of the ripe fruit 

 of the tree of knowledge. In this broad uni 

 verse of God s wisdom and love, not leashes to 



