It is the relation of Christian theology to philosophy and science with which we are specially concerned. But it is impossible to pass by the objection to theology which comes as it were _ab intra_ from the side of religion. For if it is valid, then Christianity may as well give up at once any idea of being the religion of man. Yet people say, 'Why have a theology? Human reason cannot search out "the deep things of God;" it will only put new difficulties in a brother's way; why not rest content with the words of Holy Scripture, with simple truths like "God is love," and simple duties like "Love one another," and leave theology alone?' Now without denying what George Eliot calls 'the right of the individual to general haziness,' or asserting that every Christian must be a theologian, we may surely say that Christianity is bound to have a theology. And even individual Christians, if they ever grow into the manhood of reason, must have a theology, or cease to be religious. The protest against theology from the side of religion looks modest and charitable enough till we remember that religious haziness is generally, if not always, the outcome of moral laziness; that it implies the neglect of a duty and the neglect of a gift;--the duty of realizing to the reason the revelation of Christ, and the gift of the Spirit of Truth to enable us to do it. More than this, the protest against theology in the interests of religion is irrational and suicidal. To tell a thinking man that he need not interpret to his reason what religion tells him of God, is like saying to him, 'Be religious if you will, but you need not let your religion influence your conduct.' If Christianity had been content to be a moral religion, if it had abandoned its claim to rationality and had left Greek speculation alone, it must have accepted either the Gnostic division of territory, or recognised an internecine conflict between religion and philosophy. And it did neither; but, under the guidance of the Spirit of Truth, Christian theology arose and claimed the reason of the ancient world. Thus as the religion of the Old Testament claims morality for God, so Christianity goes further and claims to hold the key to the intellectual problems of the world. So far as the nature of God is concerned, Christianity met the intellectual difficulties of the first centuries by the _Doctrine of the Trinity_.