In The Kalam Cosmological Argument, William Lane Craig explains and defends a frequently overlooked argument for God’s existence. Craig contends that the Kalam version of the Cosmological Argument, which seeks to establish a First Cause responsible for bringing the temporally finite universe into being, is a sound and persuasive argument for the existence of God.
In this book, Craig first surveys the history of the argument, particualarly as it is defended by al-Kindi, Saadia, and al-Ghazali. These three philosophers defended the minority view that the universe had a beginning a finite time ago. Using philosophical and mathematical arguments, they attempted to establish the impossibility of an actual infinite in the real world.
After a brief overview of these philosophers’ arguments concerning the beginning of the universe, Craig attempts to construct a modern case for the Kalam Cosmological Argument, which is:
1. Everything that begins to exist has a cause of its existence.
2. The universe began to exist.
3. Therefore, the universe has a cause of its existence.
Turning first to the second premise, Craig builds a four-fold defense of the conclusion that the universe began to exist. First, he argues that it is impossible for an actual infinite to exist in the real world. He shows that Cantorian set theory, though perhaps a consistent and useful mathematical system, cannot be applied to the real world without insuperable inconsistencies and contradictions. Using illustrations, he demonstrates that infinite quantities cannot be subtracted or divided without logical contradictions in the real world. But, argues Craig, it is illegitimate to simply stipulate that infinite quantities cannot be subtracted or divided in the real world, since in the real world there is nothing to stop someone from removing a book from a library with a supposedly infinite number of books. Since an actual infinite cannot exist in the real world, concludes Craig, the universe must have had a beginning, for it is impossible for an infinite number of events to have occurred or an infinite number of hours to have elapsed.
Second, Craig argues that it is impossible to form an infinite by successive addition. No matter how many numbers you count, you can still count one more. Yet, the temporal series of events occurring in the universe is a formed by successive addition. Thus, it is impossible for the universe to have existed forever.
Turning to scientific confirmation, Craig’s third argument is that the expansion of the universe, and the resulting Big Bang cosmological model, demonstrate that the universe began to exist. The evidence for the expansion of the universe, and thus the beginning of the universe, is overwhelming- confirmed by galactic redshift and microwave cosmic background radiation. Due to these findings and others, virtually all scientists now acknowledge that the universe is expanding. Such an expansion, extrapolated backwards in time, confirms that the universe began to exist.
Fourth, Craig argues that the second law of thermodynamics guarantees that the universe has not existed forever. The second law stipulates that all systems have the tendency to pass from a state of lower entropy (disorder) to higher entropy (disorder). Consider, for example, that our sun is currently using up energy, and will eventually run down. Inevitably, all the stars will burn up all their energy. Likewise, the entire universe is going to run out of usable energy, and the universe will experience a ‘heat death.’ But if scientists know that the universe will eventually be in a state of maximum entropy and heat death, then why is not the universe already in this state, if it has already existed forever? Since we are not currently in a state of heat death, it follows inescapably that the universe had a beginning a finite time ago.
After constructing an elaborate case for the second premise of the Kalam Argument, Craig briefly addresses the first premise. He contends that the premise “everything which begins to exist requires a cause” is so intuitively obvious that any argument one could make for it is bound to be less convincing than the premise itself. Craig briefly mentions two arguments. First, he notes that the causal principle is constantly verified and never falsified in our experience. Second, he claims that the Kantian mental category of causality may be used to defend the principle as an a priori intuition that makes rational thought possible.
Having defended both premises, Craig briefly reflects on the conclusion, that the universe began to exist. He then argues, via the principle of determination, that the cause of the universe must necessarily be a free personal agent, for such an agent is required in order to bring a temporal effect (the universe) from eternity.
Overall, The Kalam Cosmological Argument was a good read and an excellent contribution to natural theology. However, as a result of being outdated, Craig’s work here is largely irrelevant. Craig constructs an extraordinarily powerful case for the second premise, but unfortunately, it is the first premise which has largely come under attack in recent discussions. Thus, this book does not really address the most important contemporary objections to the argument. Craig has a number of other works in which these concerns are addressed. Therefore, unless you are looking for an historical overview of the Kalam argument or you are seeking a robust defense of a beginning of the universe, The Kalam Cosmological Argument is simply not relevant enough for contemporary discussion.