THEISM, etymologically equivalent to belief in a god or gods, and as such op posed to ATHEISM (q. v.), is now usually understood to mean the doctrine of the one, supreme, personal God, "in whom we live, and move, and have our being"—as distinguished from POLYTHEISM (q. v.), which recognizes more gods than one; from PANTHEISM (q. v.), which denies the divine personality; from AGNOSTI CISM (q. v.), which denies that we can know anything of God; and from DEISM (q. v.), which, etymologically equivalent to Theism, is generally defined as recog nizing the personality of God, but deny ing His providence and active presence in the life of the world. Deism further explicitly rejects revelation and trini tarian conceptions of the godhead, while Theism may or may not accept these doctrines.
Theism as the doctrine of the nature and attributes of God covers a large part of the field of theology and speculative philosophy. But in practice it is usually restricted to the maintenance of the the sis that God may be known; the history of the origin and development of the idea of God; and the statement, criticism, and defense of the arguments for the exist ence of God. The main part of its work is apologetic, in opposition to the hostile systems and theories, rather than a scheme of systematic THEOLOGY (q. v.).
No competent apologist now stakes the existence of God on any one argument, or exhibits the proof as a series of syl logisms. It is rather maintained that the study of human history, of human nature, especially on its moral and spir itual side, and of the world as far as science reveals it to us make for the existence of a God, demand such a pos tulate as the key to the universe, and render the belief in a personal God greatly more probable than any other thesis. But it is necessary to name what
are often referred to us the four great arguments for the existence of God. (1) The ontological argument first formu lated by St. Anselm proceeds from the notion of a most perfect being to infer his existence; without actual existence the idea would fall short of perfection.
The argument was restated in a different shape by Descartes (q. v.) and by Samuel Clarke, and, though very con temptuously treated by Kant, is still an element of the argument that without a God the world is a chaos.
(2) The cosmological argument, em ployed by Aristotle, Aquinas, and a host of Christian authors, is an application of what is called the principle of Causal ity. We cannot conceive an infinite re gression of finite causes; therefore be yond the last or first of the finite causes is the Infinite. From motion the argu ment is to a mover.
(3) The theological argument, or ar gument from design, proceeds from the order and arrangement of the universe, the reign of law and beauty and adapta tion, to the intelligent and supreme fountain of order. This is the most fa miliar of the arguments, especially on the lines laid down by Paley.
(4) The moral argument was that re lied on by Kant when he destructively criticized the other three, and forms a part of the most modern theistic argu ments. God is a postulate of our moral nature; and the moral law in us implies a lawgiver without us.