What Is Theology?
In the widest sense of the word Theology, including both natural and revealed theology, we have, among theologians who reject revelation, the systems of—(1) Atheism, or that doctrine concerning God which rejects his existence altogether.24 (2) Deism, or the system which teaches that God is the Creator of all things, but that, having once created them and impressed upon them certain laws for the regulation of their future existence, commonly called the laws of nature, He has left them to the government of those laws, and concerns Himself no more with his creation; or, in other words, this system acknowledges the existence of God, but denies his providence. (3) Theism, the system which differs from Deism by acknowledging the providence of God. The systems of Deism and Theism suppose the existence of an Almighty Creator, whose existence is independent of the universe; but there is another system, according to which the laws of Nature are in themselves the external self-existent causes of all the phenomena of the universe, and there is no causative principle external to Nature. This system takes two different forms: Materialism, which makes all the phenomena of Nature to result from the physical constitution of matter itself; and the various shades of Pantheism, which suppose an intelligent principle (anima mundi) to be inseparably connected with everything that exists, and to pervade the whole creation.
Deism properly means belief in the existence of a God, but is generally applied to all such belief as goes no further, that is to say, to disbelief of revelation. It is always applied dyslogistically, and frequently merely as a term of reproach. But the identical word, in its Greek form, theist, is not a word of disapprobation; and, consistently with established usage, may be appropriately applied as opposed to atheist, when the latter term is correctly used. For it must be observed that the term atheist has been not unfrequently employed in the sense of an unbeliever in Christianity, though at the same time professing theism.—Penny Cyclopædia.