The other reason given by Mr. Buckle why religious ideas have little influence in history is, that the religion of a nation is symptomatic of its mental and moral state. Men take the religious ideas which suit them. A religion not suited to a people cannot be accepted by it; or, if accepted, has no influence on it. This thought, argued at considerable length by Mr. Buckle, is so perfectly true as to be a truism. The religion of a people is no doubt an effect. But may it not also be a cause? It, no doubt, cannot be received by a people not prepared for it. But does it therefore exercise no influence on a people which it finds prepared? Fire cannot explode an unexplosive material, nor inflame one not inflammable. But does it follow that it effects nothing when brought into contact with one which is inflammable or explosive? A burning coal laid on a rock or put into the water produces no effect. But does this prove that the explosion of gunpowder is in no manner due to the contact of fire? "The religion of mankind," says Mr. Buckle, "is the effect of their improvement, and not the cause of it." His proof is that missions and missionaries among the heathen produce only a superficial change among barbarous and unenlightened tribes. Knowledge, he says, must prepare the way for it. There must, no doubt, be some kind of preparation for Christianity. But does it follow that Christianity, when its way is prepared, is _only_ an effect? Why may it not be also a cause? Judaism prepared the way for Christianity. But did not Christianity produce some effect on Judaism? The Arab mind was prepared for Mohammedanism. But did not Mohammedanism produce some effect on the Arab mind? Europe was prepared by various influences for Protestantism. But did not Protestantism produce some effects on Europe? It might, with equal truth, and perhaps with greater truth, be asserted that intellectual ideas are the result of previous training, and that they are therefore an effect, and by no means a cause. The intellectual truths accepted by any period depend certainly on the advanced condition of human culture. You cannot teach logarithms to Hottentots, trigonometry to Digger Indians, or the differential calculus to the Feejee Islanders. Hence, according to our author's logic, those very intellectual ideas which he thinks the only great movers in human affairs are really no movers at all, but only symptoms of the actual intellectual condition of a nation.