How is it that the full idea of the Creator,--an idea which true philosophers have sought after in all periods of history, and of which they have had, so to speak, glimpses and presentiments,--how is it that this idea is a living one only under the influence of the tradition which, proceeding originally from Abraham and Moses, has been continued by Jesus Christ? It is not impossible to point out the spiritual causes of this great historical phenomenon. Faith in God, in order to maintain itself in presence of the difficulties which rise in our minds, and--to come at once to the core of the question--the idea of the love of God, in order to maintain itself in presence of evil and of the power of evil on the earth, has need of resources which the Christian belief alone possesses. The knowledge of the Heavenly Father is essentially connected with the Gospel: this is the historical fact. This fact is accounted for by the existence of an organic bond between all the great Christian doctrines: this is my deliberate conviction. I frankly declare here my own opinions: to do so is for me a matter almost of honor and good faith; but I declare them, without desiring to lay any stress upon them in these lectures. My present object is to consider the idea of God by itself. I isolate it for my own purposes from Christian truth taken as a whole, but without making the separation in my thoughts. The thesis which I propose to maintain is common to all Christians, that is quite clear; but further; in a perfectly general sense, and in a merely abstract point of view, it is a proposition maintained equally by the disciples of Mahomet; it is maintained by J.J. Rousseau and the spiritualist philosophers who reproduce his thoughts. It is clear in fact that just as Jesus Christ is the corner-stone of all Christian doctrine, so God is the foundation common to all religions.