When, therefore, the apostle affirms that while the Athenians worshipped the God whom he proclaimed they "knew him not," we can not understand him as saying they were destitute of all faith in the being of God, and of all ideas of his real character. Because for him to have asserted they had _no_ knowledge of God would not only have been contrary to all the facts of the case, but also an utter contradiction of all his settled convictions and his recorded opinions. There is not in modern times a more earnest asserter of the doctrine that the human mind has an intuitive cognition of God, and that the external world reveals God to man. There is a passage in his letter to the Romans which is justly entitled to stand at the head of all discourses on "natural theology," Rom. i. 19-21. Speaking of the heathen world, who had not been favored, as the Jews, with a verbal revelation, he says, "That which may be known of God is manifest _in_ them," that is, in the constitution and laws of their spiritual nature, "for God hath showed it unto them" in the voice of reason and of conscience, so that in the instincts of our hearts, in the elements of our moral nature, in the ideas and laws of our reason, we are taught the being of a God. These are the subjective teachings of the human soul. Not only is the being of God revealed to man in the constitution and laws of his rational and moral nature, but God is also manifested to us objectively in the realm of things around us; therefore Paul adds, "The invisible things of him, even his eternal power and Godhead, from the creation are clearly seen, being understood by the things that are made." The world of sense, therefore, discloses the being and perfections of God. The invisible attributes of God are made apparent by the things that are visible. Forth out of nature, as the product of the Divine Mind, the supernatural shines. The forces, laws, and harmonies of the universe are indices of the presence of a presiding and informing Intelligence. The creation itself is an example of God's coming forth out of the mysterious depths of his own eternal and invisible being, and making himself apparent to man. There, on the pages of the volume of nature, we may read, in the marvellous language of symbol, the grand conceptions, the glorious thoughts, the ideals of beauty which dwell in the uncreated Mind, These two sources of knowledge--the subjective teachings of God in the human soul, and the objective manifestations of God in the visible universe--harmonize, and, together, fill up the complement of our natural idea of God. They are two hemispheres of thought, which together form one full-orbed fountain of light, and ought never to be separated in our philosophy. And, inasmuch as this divine light shines on all human minds, and these works of God are seen by all human eyes, the apostle argues that the heathen world "is without excuse, because, knowing God (γνόντες τὸν Θεόν) they did not glorify him