One who denies the existence of God:

this is called speculative atheism. Professing to believe in God, and yet acting contrary to this belief, is called practical atheism. Absurd and irrational as atheism is, it has had its votaries and martyrs. In the seventeenth century, Spinosa, a foreigner, was its noted defender. Lucilio Vanini, a native of Naples, also publicly taught atheism in France; and, being convicted of it at Toulouse, was condemned and executed in 1619. It has been questioned, however, whether any man ever seriously adopted such a principle. The pretensions to it have been generally founded on pride or affectation. The open avowal of atheism by several of the leading members of the French convention seems to have been an extraordinary moral phenomenon. This, however, as we have seen, was too vague and uncomfortable a principle to last long.

Archbishop Tillotson justly observes, that speculative atheism is unreasonable upon five accounts.

1. Because it gives no tolerable account of the existence of the world.

2. It does not give any reasonable account of the universal consent of mankind in this apprehension, that there is a God.

3. It requires more evidence for things than they are capable of giving.

4. The atheist pretends to know that which no man can know.

5. Atheism contradicts itself. Under the first of these he thus argues.

See EXISTENCE OF GOD. Some of the principal writers on the existence of a Deity have been Newton, Boyle, Cheyne, Locke, Nieuwentyt, Derham, Bentley, Ray, Cudworth, Samuel and John Clarke, Albernethy, Balguy, Baxter, Fenelon, &c, &c. Tillotson's sermon on the subject as quoted above, has been considered as one of the best in the English language.

See ser. 1: vol. 1.