In chapter three The Existence of God, Craig states that conventional wisdom says it is impossible to prove the existence of God and that, therefore, if we are going to believe in God, we must except it by faith that God exists.
Craig notes that the last half century has seen a resurgence in natural theology which is the branch of theology that seeks to prove the existence of God apart from authoritative, propositional revelation.
The God is Dead movement of the 1960s has been replaced in academia by the God is Not Dead movement. New Atheists, however, are fighting back. We combat the New Atheists with theistic arguments which are the rational arguments for the existence of God in natural theology.
The Ontological Argument was formulated by Anselm (1033-1109) and argues that God is the greatest conceivable being because if we could conceive of a being greater then that being would be God.
The Cosmological Argument is grouped into three main types.
The kalam cosmological argument promoted by Islamic theologian al-Ghazali (1058-1111) reasoned that “every being which begins has a cause for its beginning; now the world is a being which begins; therefore, it possesses a cause for its beginning.”
The next cosmological argument is Thomas Aquinas’s Unmoved Mover argument. The unmoved mover of every motion is God. He also argued that God is the First Cause of the existence of everything else.
The cosmological argument of G. W. F. Leibniz (1646-1716) is that God is the Sufficient Reason not just the cause. Leibniz wrote, “The first question which should rightly be asked will be, why is there something rather than nothing? Because nothing happens without a sufficient reason.”
Daniel Dennett caricatures this argument by saying, “Everything that exists must have a cause. What caused God?” The cosmological argument says only that every being which begins has a cause. God did not have a beginning. In fact, Dennett himself recognizes that a being “outside of time … is nothing with an initiation or origin in need of explanation. What does need its origin explained is the concrete Universe itself” (Breaking the Spell: Religion as a Natural Phenomenon, 242-244.
Based on Einstein’s General Theory of Relativity (GR), the Russian mathematician Alexander Friedman and the Belgian astronomer Georges Lemaitre predicted in the 1920s an expanding universe. In 1929, Edwin Hubble showed that the light from distant galaxies is systematically shifted toward the red end of the spectrum. This redshift was taken to be a Doppler effect indicating that the light sources were receding in the line of sight. The distances separating the galaxies were becoming greater. As one reverses the expansion and extrapolates back in time, the universe becomes progressively denser until one arrives at a state of infinite density at some point in the finite past. Now many cosmologists are identifying this past point with the big bang which is the creation not only of all the matter and energy in the universe, but also of space-time itself. In other words, there was a creation ex nihilo and matter is not eternal.
A second evidence that matter is not eternal Is the second law of thermodynamics which states that in a closed system the processes in that system will tend to run down and quit. Therefore, in time our universe will cease to be. But if this is true and the universe is eternal why has it not already run down? Like a ticking clock, it should by now have run down. The answer is, the universe is not eternal and it was wound up.
These scientific views substantiate the cosmological argument that the universe had a beginning and therefore needed a cause. Who, we believe, was God.
Never fear, atheists, have a response. Daniel Dennett argues that the universe created itself out of nothing. “It… does perform a version of the ultimate bootstrapping trick; it creates itself ex nihilo” (Breaking the Spell, 244). Aquinas, however, argued, self-creation is metaphysically absurd, since in order to cause itself to come into being, the universe would have to already exist.
If the universe had a beginning and it is absurd to believe the universe created itself, who or what did create the universe?
This transcendent cause had to be beginningless, uncaused, changeless, immaterial, and personal. This, as Aquinas was wont to remark, is what everybody means by “God.”
The Theological Argument is the argument from design and it infers an intelligent designer of the universe. Plato and Aristotle, both wholly removed from biblical revelation, believed based on design that there must be a divine designer of the universe.
Thomas Aquinas supported the theological argument believing that nothing that lacks consciousness tends toward a goal unless it is under the direction of someone with consciousness and intelligence. The arrow does not tend toward the bull’s eye unless it is aimed by the archer.
William Paley is the greatest proponent of the teleological argument in his Natural Theology of 1804 with his famous “watch-maker argument.”
The Moral Argument was advocated by William Sorley (1855-1935) which states the existence of a Being that is the embodiment of the ultimate Good, which is the source of the objective moral values we experience in the world. Sorley believes that the most serious objection to this worldview is the problem of evil. Sorley argued that suffering and evil are possible in a theistic worldview if finite minds are gradually recognizing moral ends that they are free to accept or reject.