THE object of this work is to state in plain and popular speech, the reasonableness of certain great truths which lie at the foundation of Christian belief. It has had its inspiring motive in the conviction-one which must be to every Christian mind a source of strength, solace, and security-that Christianity claims to rest upon a reasonable basis, and has the highest interest in using, in prizing, in defending the light of human reason with which God has endowed us. Religion means nothing if not the service of God, and God Himself requires that our service shall be "reasonable" (Rom. xii. 1), and that we shall not only possess, but be ready to give, "a reason for the hope that is in us" (1 Peter iii. 15). This cordial appreciation of the value and claim of human reason is a characteristic of Christianity, upon which we can hardly insist too much in an age of doubt and denial, and, I might add, of philosophical systems which are not uncommonly built upon an initial act of treason to our rational nature.We hold that it is reasonable to believe in the existence of a Personal and Intelligent God. We hold that we have reasonable evidence for believing that this God has spoken to mankind. And, God being Truth, we hold that it is supremely reasonable to believe whatever He has said to us. God speaking to us is Revelation, our believing what He says is Faith. Thus Faith and Revelation have their groundwork in reason-reason, which tells us that God exists; reason, which assures us of the fact that He has spoken; reason, which inculcates the duty of believing what He says. Never, then, can the Christian disparage human reason, without at the same time disparaging the very ground which underlies the spiritual house he lives in. He can never forget that the light of Reason, not less than that of Revelation, proceeds from Him, the light of Whose "countenance is signed upon us" (Ps. iv. 7), and" Who is the Light which enlighteneth every man who cometh into this world" (John 1). The Catholic Church has shown her wisdom in watchfully defending the right and the veracity of human reason against those who had impugned it. She did so against Luther, who, in teaching that our nature was wholly vitiated and corrupted by the fall, described human reason, the highest part of it, as a "beast," and heaped upon it some of the most vilifying epithets which he could find in his vocabulary of vituperation. She did so against De la Mennais, who sought unwisely to diminish and depreciate the scope of natural reason, with a view to magnify and expand the domain of Faith in the sphere of human judgment.She did so at the Vatican Council, when she vindicated for human reason its sublime function as serving as the natural basis of the truths of revelation. As long as the Catholic Church is the guardian of Faith, so long must she continue to be the defender of Reason.