I am currently reading a book by the late Professor Victor Stenger on the (lack of) scientific evidence for God’s existence. When I came to what is posted below, since it dealt with kalâm I remembered this discussion and thought I would chuck an extract from the book into it.
‘[William Lane] Craig claims that if it can be shown that the universe had a beginning, this is sufficient to demonstrate the existence of a personal creator. He casts this in terms of the kalâm cosmological argument, which is drawn from Islamic theology. The argument is posed as a syllogism:
1) Whatever begins to exist has a cause.
2) The universe began to exist.
3) Therefore, the universe has a cause.
‘The kalâm argument has been severely challenged by philosophers on logical grounds, which need not be repeated here since we are focusing on the science. In his writings, Craig takes the first premise to be self-evident, with no justification other than common, everyday experience. That’s the type of experience that tells us the world is flat. In fact, physical events at the atomic and subatomic level are observed to have no evident cause. For example, when an atom in an excited energy level drops to a lower level and emits a photon, a particle of light, we find no cause of that event. Similarly, no cause is evident in the decay of a radioactive nucleus.
‘Craig has retorted that quantum events are still “caused,” just caused in a nonpredetermined manner—what he calls “probabilistic causality.” In effect, Craig is thereby admitting that the “cause” in his first premise could be an accidental one, something spontaneous—something not predetermined. By allowing probabilistic cause, he destroys his own case for a predetermined creation. We have a highly successful theory of probabilistic causes—quantum mechanics. It does not predict when a given event will occur and, indeed, assumes that individual events are not predetermined. The one exception occurs in the interpretation of quantum mechanics given by David Bohm. This assumes the existence of yet-undetected subquantum forces. While this interpretation has some supporters, it is not generally accepted because it requires superluminal connections that violate the principles of special relativity. More important, no evidence for subquantum forces has been found.
‘Instead of predicting individual events, quantum mechanics is used to predict the statistical distribution of outcomes of ensembles of similar events. This it can do with high precision. For example, a quantum calculation will tell you how many nuclei in a large sample will have decayed after a given time. Or you can predict the intensity of light from a group of excited atoms, which is a measure of the total number of photons emitted. But neither quantum mechanics nor any other existing theory—including Bohm’s—can say anything about the behavior of an individual nucleus or atom. The photons emitted in atomic transitions come into existence spontaneously, as do the particles emitted in nuclear radiation. By so appearing, without predetermination, they contradict the first premise.
‘In the case of radioactivity, the decays are observed to follow an exponential decay “law.” However, this statistical law is exactly what you expect if the probability for decay in a given small time interval is the same for all time intervals of the same duration. In other words, the decay curve itself is evidence for each individual event occurring unpredictably and, by inference, without being predetermined.
‘Quantum mechanics and classical (Newtonian) mechanics are not as separate and distinct from one another as is generally thought. Indeed, quantum mechanics changes smoothly into classical mechanics when the parameters of the system, such as masses, distances, and speeds, approach the classical regime. When that happens, quantum probabilities collapse to either zero or 100 percent, which then gives us certainty at that level. However, we have many examples where the probabilities are not zero or 100 percent. The quantum probability calculations agree precisely with the observations made on ensembles of similar events.
‘Note that even if the kalâm conclusion were sound and the universe had a cause, why could that cause itself not be natural? As it is, the kalâm argument fails both empirically and theoretically without ever having to bring up the second premise about the universe having a beginning.’
Stenger, Victor J.. God: The Failed Hypothesis. Prometheus. Kindle Edition.
Professor Stenger nevertheless does go on to examine the second premise, but I have perhaps exceeded the bounds of fair dealing more than sufficiently already. The book cost me £8.69 in the Kindle edition, so not exactly a bank-breaker if anyone wanted to read on.