The Kalam: An Overview & Defense

By Ronald Cram

William Lane Craig is famous for resurrecting and defending the Kalam Cosmological Argument (KCA). The argument appeals to both philosophical and scientific evidence for the beginning of the universe. If the Kalam is sound, it seems to prove the existence of God.

Kalam Cosmological Argument

The question is raised: Is the argument sound given our modern, scientific understanding of cosmology? In this essay I will review and examine the premises of the Kalam to see if we have good reason to affirm them as probably true. The standard form of the KCA goes as follows:

1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.

We can add the following steps:

4. The universe (all space, time, and matter) cannot cause itself.
5. The cause of the universe must be spaceless, timeless, immaterial, and uncaused.
6. This uncaused, immaterial and timeless cause of the universe is what everyone means by God.
7. Therefore, God exists.

The argument is valid, but are the premises true? Science uses Bayesian probability theory to assign a probability to a hypothesis. I will follow that procedure for each of the premises.

Step #1

All science is based on cause and effect relationships. Zero evidence exists that this premise is false and so this premise has never faced any serious or informed challenges. In our daily experience, objects do not pop into existence uncaused.

Scientists have proposed a number of possible causes of the Big Bang including colliding branes in string theory, false vacuum in inflationary theory, and quantum fluctuations in quantum mechanics. Each of these ideas propose a “universe generator” of some type that must exist prior to our Big Bang. Scientists recognize that the Big Bang must have a cause.

Some have attempted to claim that quantum fluctuations are uncaused, but this claim is untrue. Quantum fluctuations are caused by the energy in the vacuum. While no one can predict where quantum fluctuations will appear, the number of fluctuations within a given volume and time are quite predictable.

Others have proposed that while things within the universe need a cause to begin to exist, we have no reason to believe the universe as a whole needs a cause. This is special pleading of the most irrational type. If objects within the universe need a cause (when the atoms and molecules already exist), then it is even more true that the universe as a whole needs a cause to exist because an extra step is required (the creation of matter, energy, space and time). A Bayesian probability can be assigned to this premise of 99+%.

Step #2

This is more complicated. Stated simply, the standard cosmology is that the universe is 13.8 billion years old. This means the universe began to exist 13.8 billion years ago. While it is true that theorists are working on models for a past eternal universe, a Bayesian probability can be assigned to this premise of 98%.

For those who are not interested in cosmology, you may skip to the discussion of the third premise. For those interested in cosmology and a defense of this Bayesian probability, read on.

William Lane Craig often refers to BGV theorem in his debates with atheists. (The theorem is often misunderstood to be a singularity theorem. It is not. It is an incompleteness theorem. But it is completely compatible with the singularity theorems.) BGV theorem states that any universe which is on average expanding throughout its history cannot be eternal into the past but must have had a beginning. This is an extremely robust theorem. Within a classical spacetime, BGV theorem does not depend upon any particular energy condition (low energy, high energy) nor does it depend on any particular solution to Einstein’s equations. The fact the theorem is so robust makes it very difficult to evade. It applies to multiverse theories and cyclic universe theories. Any past eternal cosmological theory must evade BGV theorem.

In his debate with William Lane Craig, Sean Carroll referred to his paper titled “What if time really exists?” and its Quantum Eternity Theorem.

In Carroll’s post-debate reflections, he writes:

“Indeed, I quoted a stronger theorem, the “Quantum Eternity Theorem” (QET) — under conventional quantum mechanics, any universe with a non-zero energy and a time-independent Hamiltonian will necessarily last forever toward both the past and the future. For convenience I quoted my own paper as a reference, although I’m surely not the first to figure it out; it’s a fairly trivial result once you think about it.” (Click here)

The QET is not a “stronger theorem” in any sense. Most cosmologists believe our universe has zero net energy. So any model built on a non-zero energy is extremely unlikely. Also, the theorem has the requirement of “under conventional quantum mechanics.” But a beginning necessarily requires something other than conventional quantum mechanics. There’s nothing to prevent a beginning of our conventional quantum mechanics. In reality, Carroll’s QET is not at all helpful to his argument. Aron Wall provides a cosmologist’s assessment of Carroll’s claims and his use of QET (click here).

Proposed Models

Some models have been proposed than can evade BGV theorem. We will look at a few of these theories in greater detail.

A. The first of these is the Aguirre-Gratton model supported by Sean Carroll in his debate with Craig. Obviously, Carroll thinks this model is the strongest possible, the most likely to be true, or he wouldn’t have used it to support his position that the universe may be past eternal. But what is the Bayesian probability this model describes our universe?

In the Abstract of his paper “Eternal inflation and its implications,” Alan Guth writes:

“Although inflation is generically eternal into the future, it is not eternal into the past: it can be proven under reasonable assumptions that the inflating region [our universe] must be incomplete in past directions [have a beginning], so some physics other than inflation is needed to describe the past boundary of the inflating region.”

On page 14 of the same paper Guth writes:

“If the universe can be eternal into the future, is it possible that it is also eternal into the past? Here I will describe a recent theorem [43] which shows, under plausible assumptions, that the answer to this question is no.”

According to Guth, under “reasonable assumptions” and “plausible assumptions” the BGV theorem cannot be avoided. On page 16, Guth discusses the Aguirre-Gratton model with its reversal of the arrow of time and explains that this model does evade BGV theorem. The natural conclusion is that the Aguirre-Gratton model does not have reasonable or plausible assumptions. Aguirre and Gratton have not put forward any plausible mechanisms that might cause the arrow of time to reverse and no reversal of time has ever been observed.

Remember this is the best model that Sean Carroll had to represent his view that the universe is past-eternal. A Bayesian probability that the Aguirre-Gratton model applies to our universe is <1%.

B. Cosmology from Quantum Potential Model – Because the BGV theorem applies to classical spacetimes, another way to evade the theorem is to appeal to the uncertainty of quantum mechanics. One example is the paper “Cosmology from Quantum Potential.”

However, this cosmological model has serious problems. A recent paper titled “Perturbative Instability of Cosmology from Quantum Potential” has the following Abstract:

“Apart from its debatable correctness, we examine the perturbative stability of the recently proposed cosmology from quantum potential. We find that the proposed quantum corrections invoke additional parameters which apparently introduce perturbative instability to the Universe.”

Our universe is stable. This model does not produce a universe like the one we observe. The Bayesian probability of this model being correct is less than the Aguirre-Gratton model and is <1%.

C. Emergent Universe Models – This class of models successfully evade BGV theorem. The idea is that a “cosmic egg” that exists forever until it breaks open to produce an expanding universe. Proponents of these ideas include Ellis, Barrow, Campo, Wu, and Graham.

Mithani and Vilenkin show that this class of models can collapse quantum mechanically, and therefore cannot have an eternal past.

A Bayesian probability of Emergent Universe Models being correct is <1%.

Side Note: What About Guth?weird-guth-sign

Someone may mention the photo of Alan Guth holding a sign at the Carroll/Craig debate that read [The universe is] very likely eternal but nobody knows.” Why would Guth pose holding that sign when all of his scientific papers say the universe had a beginning? Some assumed Guth was going to publish a new paper that explained his change of view, but it’s been three years and no paper has been published supporting a change in the science.

Perhaps Guth posed for that picture just as a favor to Carroll.

In order to defeat premise #2, skeptics must be able to show that a past-eternal universe is more likely than a universe of a finite age. While a number of past-eternal models have been proposed, the cosmological community has rejected all of them as highly unlikely. A Bayesian probability can be assigned to premise (2) of 98%.

Step #3

The third step of the argument is the rational conclusion of the first two premises. A Bayesian probability can be assigned to this conclusion of 98%.

Step #4

The fourth premise – “The universe cannot cause itself” – seems non-controversial. However, cosmologists (driven by their dislike of the way a beginning of the universe points to creation by God) have proposed ideas attempting to challenge this premise. Lawrence Krauss’s book, A Universe from Nothing, was one of the first of these proposals to get a wide audience. The idea, first proposed by Edward Tryon, is that the universe is a quantum fluctuation. Physicist Don Page pointed out that Krauss’s idea is not really “from nothing” because quantum fluctuations require a quantum field (which is something). Since the quantum field must exist before the Big Bang, this is not a universe from nothing at all.

Alexander Vilenkin modified Tryon’s idea referring to the origin of the universe as a “quantum nucleation” that happened before the existence of any matter, energy, time or space. In order words, the quantum nucleation happened in the absence of a quantum field. Not only is this logically incoherent as things happening before time require time, but this idea is problematic for most physicists because the theory makes an untestable claim. Scientifically untestable claims are not scientific. The probability the universe can cause itself is <1%.

Step #5

“The cause of the universe must be spaceless, timeless, immaterial, and uncaused” is mostly non-controversial. If the universe is defined as “all matter, energy, space and time” and the universe cannot create itself, then it follows that the cause of the universe must be spaceless, timeless and immaterial. Some may argue that the cause does not necessarily have to be uncaused. But if a contingent being of finite age were the creator, that being would not be the ultimate answer.

The real Creator would be the one who created the intermediate being. An infinite causal regress is a logical absurdity and has been rejected by philosophers since the time of Aristotle. A Bayesian probability can be assigned to this premise of 99%.

Step #6

“This uncaused, immaterial and timeless cause of the universe is what everyone means by God” is largely uncontroversial. A Bayesian probability can be assigned to this premise of 99%.

Step #7

“Therefore God exists” is a rational conclusion. A Bayesian probability can be assigned to this conclusion of >95%.

Whether this God is the God of the Bible or some other God is a separate question and requires additional evidence and reasoning.

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The Necessity of God’s Existence: Ontological Arguments Worth Considering

By Brian Chilton

One of the more difficult of the apologetics arguments to understand is that known as the ontological argument. The ontological argument finds root in Anselm of Canterbury’s famed declaration, “God is that, than which noting greater can be conceived.”[1] This is the say, God is the greatest of all possible beings. God, properly understood, is maximally great. Nothing could be greater than God. Thus, Anselm argues that if it is possible to conceive of the greatest possible beings, then that greatest possible being must exist. There is much to unpack in this argument. However, I would like to focus on arguments that provide reasons to believe that God is a necessary being.

Ontological Argument God

Before we look at some arguments for the necessity of God’s existence, we must first define a necessary being. A necessary being is a being whose existence is mandatory due to a result of that being’s existence (i.e., contingency). For example, I exist only because of the necessity of my parents’ existence. My existence is contingent (based upon) the necessity of their existence. My parents’ existence is contingent (based upon) the necessity of their parents’ existence (my grandparents). The logical line of necessity continues until one finds the necessity of a maximally great being—a being that is transcendent, omnipotent, omniscient, omnipresent, and omnibenevolent. We know that maximally great being as God. Let’s look at three or four modern ontological arguments that make the case for the necessity of God’s existence.

  1. Necessity of God Found in Logical Necessity.

As we already unpacked the argument from necessity, we have found that God’s existence is mandatory. However, the logical necessity of God’s existence is found in the following argument presented by Douglas Grootius:

  1. God is defined as a maximally great or Perfect Being.

  2. The existence of a Perfect Being is either impossible or necessary (since it cannot be contingent).

  3. The concept of a Perfect Being is not impossible, since it is neither non-sensical nor self-contradictory.

  4. Therefore (a) a Perfect Being is necessary.

  5. Therefore (b) a Perfect Being exists.[2]

The first premise notes that God is defined as a maximally great being, or Perfect Being. Premises 2 and 3 demonstrate the logical necessity that a Perfect Being is either an impossibility or a necessity. Since the existence of a Perfect Being is neither impossible, nonsensical, nor self-contradictory, the existence of a Perfect Being is shown to be a necessary concept. The atheist would need to demonstrate that God’s existence is impossible (which itself is impossible), nonsensical (which is actually found in a worldview that postulates that things magically pop into existence without any cause), or self-contradictory. The only means that the non-believer has to disprove the necessity of God’s existence in my humble opinion is to show that there is a self-contradiction in God’s existence. Yet, it appears to me that there are greater self-contradictions in viewing the universe without the existence of God, thereby strengthening the necessity of a Perfect Being. The former is an impossible task, the middle is a task that some have attempted…and failed, and the third is inherently flawed.

Looking at this model from a different perspective, consider Alvin Plantinga’s take on Norman Malcolm’s argument, presented by Norman Geisler:

  1. If God does not exist, his existence is logically impossible.

  2. If God does exist, his existence is logically necessary.

  3. Hence, either God’s existence is logically impossible or else it is logically necessary.

  4. If God’s existence is logically impossible, the concept of God is contradictory.

  5. The concept of God is not contradictory.

  6. Therefore, God’s existence is logically necessary.[3]

Let’s unpack this argument. If God did not existence, his existence would be a logical impossibility like the existence of magical unicorns. If God does exist, then his existence would be a logical necessity—like the example of my parents’ existence as given above. Thus, God’s existence would be logically necessary if he exists or logically impossible if he does not exist. If God’s existence is impossible, then the idea of God is contradictory. God’s existence is not a contradiction; therefore, God is a logical necessity.

I personally like these arguments as I find the existence of God an absolute necessity. Non-theistic arguments often lead to bizarre absurdities which are at times irreconcilable. Christian theism is the most coherent of all worldview, thus the existence of the Christian God is a logical necessity. There is another take to this argument that demands consideration: the necessity of God found in possible worlds.

  1. Necessity of God Found in Possible Worlds.

A possible world is a hypothetical scenario that describes the various ways that the world could be. We live in the actual world, however the would could have been much different. With that in mind, consider Alvin Plantinga’s ontological argument from possible worlds.

  1. It is possible that a maximally great being exists.

  2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world. That is, God’s existence is not impossible (logically contradictory), so we can conceive of a world in which God does exist.

  3. If a maximally great being exists in some possible world, then it exists in every possible world. (Otherwise, it would not be maximally great.)

  4. If a maximally great being exists in every possible world, then it exists in the actual world.[4]

Let’s unpack Plantinga’s difficult argument. Nearly everyone would agree that it is at least possible that a maximally great being exists—that is, God. Since God’s existence is not impossible, then it is conceivable that God exists in some possible world. If it is possible that God exists in one possible world, then it is possible that he exists in every possible world including the actual world in which we live. Some will argue, “But yeah, it is possible that magical unicorns exist in some possible world. So, does that mean that magical unicorns must exist in this world?” Absolutely not! The existence of the magical unicorn is not a necessity. Since I am a contingent being, it is necessary in all possible worlds that I have a reason for my existence (by my parents or another set of parents). If God, being a necessary being, is possible in some possible world, he is possible in all possible worlds and is in fact found in the actual world. Confusing? Yes. But logically coherent? Absolutely!

Let’s now look at the last ontological argument of God’s necessity as it pertains to the Second Law of Thermodynamics.

  1. Necessity of God Found in Second Law of Thermodynamics.

The Second Law of Thermodynamics states that entropy increases as time progresses. Entropy is the disorder that occurs over time. Think of a wind-up toy. The wind-up toy is wound up and allowed to wind itself down. The winding down of the toy is the state of entropy. The same occurs with heat. Over time, heat cools until all heat is lost (i.e., heat death). The Second Law of Thermodynamics states that the universe is losing energy as it continues to exist. This will ultimately lead to a complete loss of heat unless there is an intervention from outside the universe. The following modus Tollens argument, presented by Groothius, notes how the Second Law of Thermodynamics argues for the finite nature of the universe and the necessity of God’s existence.

  1. If the universe were eternal and its amount of energy finite, it would have reached heat death by now.

  2. The universe has not reached heat death (since there is still energy available for use).

  3. Therefore, (a) the universe is not eternal.

  4. Therefore, (b) the universe had a beginning.

  5. Therefore, (c) the universe was created by a first cause (God).[5]

Let’s unpack this argument. If it were possible that the universe is eternal with finite energy (which is observable), then the universe would have reached a heat death already. However, that has not occurred. Due to the absence of such an event, this proves that the universe is finite and had a beginning. If the universe had a beginning, the cause is most plausible to have been attributed to God. “Wait!” the skeptic may say. “Isn’t it possible that a multiverse gave birth to the universe?” Yes, it is possible. However, it has been shown in the BVG Theorem (named by its discoverers Borg, Vilenkin, and Guth) that all physical universes must have a finite past and an absolute beginning. So, the skeptic does nothing by arguing for a multiverse outside of pushing the necessity of God’s existence back a step or two.


It is true that these arguments are quite complex. But if one takes the time to evaluate and understand these versions of the ontological argument, I think one will find the necessity of God’s existence is rooted in a wealth of logical and philosophical certitude. Logically speaking, God’s existence is a necessity as it is demanded by logic and the data of causal relations in the actual world.

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