Theism has come to us mainly through Christianity. But Christianity itself rests on theism; it presupposes theism. It could only manifest, establish, and diffuse itself in so far as theism was apprehended. The belief that there is one God, infinite in power, wisdom, and goodness, has certainly not been wrought out by each one of us for himself, but has been passed on from man to man, from parent to child: tradition, education, common consent, the social medium, have exerted great influence in determining its acceptance and prevalence; but we have no right to conceive of them as excluding the exercise of reason and reflection. We know historically that reason and reflection have not been excluded from the development of theistic belief, but have been constantly present and active therein; that by the use of his reason man has in some countries gradually risen to a belief in one God; and that where this belief existed, he has, by the use of his reason, been continuously altering, and, it may be hoped, extending and improving his views of God's nature and operations. We know that in Greece, for example, the history of religion was not a merely passive and traditional process. We know as a historical fact that reason there undermined the polytheism which flourished when Homer sang; that it discovered the chief theistic proofs still employed, and attained in many minds nearly the same belief in God which now prevails. The experience of the ancient classical world is insufficient to prove that a purely rational philosophy can establish theism as the creed of a nation; but it is amply sufficient to prove that it can destroy polytheism, and find out all the principal arguments for theism. We know, further, that in no age of the history of the Christian Church has reason entirely neglected to occupy itself in seeking the grounds on which the belief of God can be rested. We know that reason is certainly not declining that labour in the present day. The theistic belief, although common to the whole Christian world, is one which every individual mind may study for itself, which no one is asked to accept without proof, and which multitudes have doubtless accepted only after careful consideration. It comes to us so far traditionally, but not nearly so much so as belief in the law of gravitation. For every one who has examined the evidences for belief in the law of gravitation, thousands on thousands have examined the evidences for the existence of God.