The kalam argument is an altered form of the cosmological argument. It is intended to circumvent the infinite regress problem contained within the traditional cosmological argument by altering the premises. The arguments dates back to the Islamic apologist al-Ghāzāli (1058-1111). 
William Lane Craig's version of the kalam cosmological argument is as follows:
- Everything that begins to exist has a cause.
- The universe began to exist.
- Therefore, the universe must have a cause.
The distinction between the first premise and the traditional cosmological argument's principle of sufficient reason is that it distinguishes effects in general from those that have a beginning. This qualification leaves open an interesting possibility that some things in the universe might exist that never began to exist. But Craig is not that sloppy, so before we jump on this observation, we need to address the kalam argument's second premise and its support.
The kalam argument's second premise—"The universe began to exist"—is a claim that seems more of a presupposition than a fact, but watch how it is supported:
- An actual infinite cannot exist.
- A beginningless series of events is an actual infinite.
- Therefore, the universe cannot have existed infinitely in the past, as that would be a beginningless series of events.
The important term here is, of course, "actual infinite." Wikipedia has the following to say about actual infinities:
- "Actual infinity is the notion that all (natural, real etc.) numbers can be enumerated in any sense sufficiently definite for them to form a set together. Hence, in the philosophy of mathematics, the abstraction of actual infinity is the acceptance of infinite entities, such as the set of all natural numbers or an arbitrary sequence of rational numbers, as given objects."
- "The mathematical meaning of the term actual in actual infinity is synonymous with definite, completed, extended or existential, but not to be mistaken for physically existing. The question of whether natural or real numbers form definite sets is therefore independent of the question of whether infinite things exist physically in nature."
Begging the question and special pleading to avoid infinite regress
The kalam argument seems to have been worded specifically to address the refutation of the cosmological argument, as it made the qualification that only things that begin have causes. The kalam arguer will simply state that God didn't begin, and so no regress occurs and no Creator of God is necessary.
In Dan Barker's article Cosmological Kalamity, he writes
The curious clause “everything that begins to exist” implies that reality can be divided into two sets: items that begin to exist (BE), and those that do not (NBE). In order for this cosmological argument to work, NBE (if such a set is meaningful) cannot be empty, but more important, it must accommodate more than one item to avoid being simply a synonym for God. If God is the only object allowed in NBE, then BE is merely a mask for the Creator, and the premise “everything that begins to exist has a cause” is equivalent to “everything except God has a cause.” As with the earlier failures, this puts God into the definition of the premise of the argument that is supposed to prove God’s existence, and we are back to begging the question.
In other words, the set of items that do not begin to exist must be pluralized - otherwise it is just another word for God.
The wording of Kalam is arguably a form of special pleading on the part of the theist. As Richard Dawkins put it, the cosmological argument makes "the entirely unwarranted assumption that God himself is immune to the regress." Whether we qualify the first premise to exclude non-beginning things (as the kalam argument does) or not (as the cosmological does), the essential question is why it is more logically defensible to claim that for the rule that everything must have a cause, an exception is made for God but not for the natural universe as a whole? Why does god not begin? It appears to be a wholly arbitrary choice.
Not all events necessarily have causes
- Main Article: Not all events necessarily have causes
The argument asserts that "everything that begins to exist has a cause". However, this is arguably a false statement and a hasty generalization. It is possible that some events, particularly on the quantum scale (such as in the early universe), do not have causes (or at least we do not fully understand the cause at this time). Thunderf00t's video on Kalam questions the validity of using everyday concepts like "everything that begins to exist has a cause" in extreme situations such as the beginning of the universe.  Hume argues the only way to know if principles (such as causality) hold in very different conditions is to have direct experience of it.
Fallacy of Composition
- Main Article: Fallacy of composition
In the first premise, Craig declares "everything that begins requires a cause," and goes on to place the universe at the same logical level as its contents.
The first premise refers to every "thing," and the second premise treats the "universe as if it were a member of the set of "things." But since a set should not be considered a member of itself, the cosmological argument is comparing apples and oranges.
Describing the way physical objects within the universe behave relies on induction and physical laws, neither of which apply in the absence of a spacetime universe. Everything we are familiar with is an object within a set (the universe). It is a fallacy of composition to assert that the properties of things we are familiar with (objects within the set) are also properties of the set as a whole (the universe). Example: "Each part of an airplane has the property of being unable to fly. Therefore the airplane has the property of being unable to fly." The conclusion doesn't follow because the only way to determine whether the airplane has the property of being able to fly or not would be to get outside the plane (set) and then make observations. Unfortunately we are stuck inside the universe, so any conclusions we can draw about individual components of the universe (within the set) do not necessarily apply to the set as a whole.
See Russell's paradox for issues that arise from allowing a set to be a member of itself.
Equivocation of "beginning to exist"
Kalam also equivocates on the first premise when it refers to everything that "begins to exist". Presumably this premise is referring to everything around us on this planet--everything in your house, everything on the streets, everything we see in the cosmos. However all of these things did not "begin to exist" in the same sense theists are claiming the universe "began to exist" (creation ex nihilo). According to the laws of thermodynamics, matter can neither be created nor destroyed, and everything we are familiar with is a actually reconfiguration of preexisting matter than has been around for billions of years. The atoms that comprise people, places, and planets do not "come into existence" in the same sense Kalam is claiming the universe came into existence (matter appearing from a previous state of non-being/non-existence). Rather they have always existed in some form, and the objects we see around us are merely the latest rearrangements of those atoms. So in speaking of the universe requiring a "cause" for it's existence, Kalam is not referring to it as you would an automobile, which is being "caused" by a group of laborers rearranging physical matter into the form of a car, or mountains being "caused" by the shifting of tectonic plates (also made of atoms which have been around since the big bang), but of something being caused by creation ex nihilo, which is not at all the type of creation we are familiar with in every other circumstance. Kalam therefore is using a word game to equivocate between the behavior of matter and the origin of matter. This is an equivocation between wildly different things.
In summary: Kalam proponents believe God made the universe exist ex nihilo. But everything around us only "begins to exist" in a trivial sense, as rearrangements of preexisting, uncreated stuff. Since the universe is literally the only example of something truly "beginning to exist" from a previous state of nothingness, this means there is a sample set of one in this category, leaving no inductive support for the premise that "whatever begins to exist (ex nihilo) has a cause".
Once the argument is reformulated to take into account the hidden premises, it looks like this:
- Every rearrangement of pre-existing matter has a cause. (supported by every observation, ever.)
- The universe began to exist from absolute nonexistence, NOT from a rearrangement of pre-existing matter.
- Therefore the universe has a cause.
In other words:
- Every X has a cause.
- The universe Y.
- Therefore the universe has a cause.
As you can see, once the equivocation is made plain, the argument is invalid.
There is a further type of equivocation on the phrase "begins to exist". Premise 1 refers to things that begin to exist within time. In other words, there was a time when a thing did not exist, followed by a time when it existed. This is not the case with the universe, since time is part of the universe. The universe is a finite age (13.8 billion years), and because time did not come into existence until after the inflation began, there is literally NO TIME at which the universe did not exist. It has existed at every point in time. Rephrasing the argument to accurately include this information, we get something like this:
Let X = "a thing which began to exist a finite time ago after a point when it did not exist"
Let Y = "a thing which has existed for a finite time, but which exists at every point in time"
- Everything that is X has a cause for it's existence.
- The Universe is Y.
- Therefore the universe has a cause for it's existence.
Once again, equivocation is at play. Premise 1 and 2 are comparing apples and oranges. The universe has existed at every moment in time and did not begin to exist in the same way that every object in P1 began to exist, so the argument is invalid.
Special pleading that the universe is not necessarily existent
If God not having a beginning is not a problem for Craig and other defenders of this argument, why is it a problem for the natural universe? To answer this, we must look at a further problem. This problem concerns the definition of god used in Kalam and the cosmological argument. A theologian might reply this counter argument and insist that the decision is not arbitrary, and that god must be allowed to have these attributes that the kalam argument seems to imply. He may say that the argument is an attempt to show the need for there to be a God that has the attributes that we cannot find in the universe. He might say that because we know that everything in the universe needs a cause and that the idea of infinite time is nonsense, there must be this being with these unique attributes. That is, there must be this being that does not begin, has no creator, and is thus able to create the universe. But this is just a bald assertion. The lack of human imagination when it comes to solving mysteries at the boundaries of current knowledge is not a good reason to invoke a hypothetical entity with mysterious powers that enable it to be immune from paradoxes.
A-priori arguments cannot establish matters of fact
- Main Article: Proof by logic
Overall, this argument is an example of a proof by logic, where philosophers attempt to "demonstrate" god with a logical syllogism alone, devoid of any confirming evidence. This is arguably inappropriate for establishing matters of fact.
Is God distinct from the universe?
Let S1 = a state of affairs in which the Universe did not exist, and S2 = a state of affairs in which the Universe did exist.
The theist is trying to claim that the Universe began to exist, that is, there was a state in which there was God, "and then" there was a state in which there was the Universe. In other words, they want to say S1 "and then" S2. In order to do that, they must show that S1 and S2 are distinct. The possibilities are:
- The Universe never began to exist
- The Universe never existed
- S1 and S2 follow each other in time
- Some agent in S1 is the atemporal cause of S2
If we can eliminate all four examples, then there is no way to distinguish between the two states. If that is the case, then there is no "beginning" - no state at which the Universe began to exist, thus undermining the conclusion.
If we try to prove by contradiction that the Universe never began to exist, the contradiction becomes evident. By assuming the Universe began to exist, it rules out (1). The Universe exists, so that rules out (2). (3) is disproven by the fact that time is a property of the Universe, and therefore can't be applied outside of the Universe. (4) can't be true because Craig defines "atemporal causation" as follows:
To borrow an illustration from Kant, a heavy ball’s resting on a cushion is the cause of a depression in the cushion, even if the ball has been resting on the cushion from eternity past.
However, this cannot be used to distinguish between S1 and S2 because it requires cause and effect to be simultaneous. S1 and S2 cannot be simultaneous, as the Universe would exist at the same instant that it doesn't exist - a contradiction. By assuming that the Universe began to exist, we have ruled out all explanations for how it could have begun to exist. Thus, we cannot distinguish at the moment between S1 and S2 - undermining their conclusion.
- Main Article: Ultimate 747 gambit
The God hypothesis is not only unnecessary, it is not parsimonious. In order to explain something apparently designed and which cannot create itself, a being is conjured into existence which would require even more unlikely explanation.
Why only one cause?
In the construction of a house, there may be twenty people involved. There may be a large amount and wide variety of materials. There must be an appropriate location, and a diverse set of conditions that allowed the entire process to take place. Yet, the first premise would have us believe that all of this comprises just one "cause." This fails even on the most basic intuitive level, and even when it involves an object with which we are intimately familiar. Discussing something as foreign to our intuitions as the beginning of time would seem to compound the problem further.
However, even if we grant that each "thing" in the universe has exactly one cause, and that postulating an uncaused cause is sufficient to explain the origin of all things, it still would not follow that there could be only one uncaused cause. There could be several such influences working in concert, as polytheists would have us believe. There could be millions of uncaused causes that began separately but whose creations have since intermingled to form the universe we have now. In short, it isn't clear why anyone should suggest "a cause" rather than an unknown number of them - unless, of course, one's goal is to support an ideology that claims a singular creator for other reasons.
Natural processes are not ruled out
Even if you accept Kalām, it does not distinguish between a timeless multiverse, a timeless deity, or any other timeless process that might give rise to a universe. New Apologetics suggested a hypothetical "Quantum Minds Theory" in which many non-beneficent, non-omniscient, non-temporal minds exist and the universe begins when one mind shifts to break the logjam/equilibrium of competing ideas in the mind collection. 
- "On QMT, the physical world is not a design of God, but is the ontological by-product of an imbalance in the network of opposition between a vast multitude of non-spatiotemporal minds."
They argue this hypothesis is a better fit with the observed universe than traditional theism.
Unsupported premises relating to an actual infinite
- Main Article: Infinite regress does not occur
Block theory of time is compatible with an actual infinite series of events
One view of time is that the past, present and future always exist. Therefore there is no restriction on how much future or past there might be; it might even be an actual infinite. 
Problem of evil
- Main Article: Kalam Cosmological Problem of Evil
Based on the premises of Kalam, evil may or may not have a cause (depending on if evil had a beginning). Either the source of evil is divine, or God could not or would not destroy evil.
- Main Article: The first cause implies God exists
Cosmological arguments have a weak conclusion that does not entail God exists. Although some other variation of the Kalām argument or Cosmological argument may be internally consistent even if all the terms given are agreed upon by all parties concerned, the argument actually makes no effort to demonstrate anything tangible in nature regarding the manifestation of a God. An example analogous to the Kalām argument would be a geometry proof on some type of polygon. Even though the entire table of proofs is totally internally consistent, it does not demonstrate that the actual polygon exists in nature. An exhaustive effort to prove all the angles of a triangle will always add up to 180 degrees says nothing about whether or not triangles exist.
- ↑ 
- ↑ Why do people laugh at creationists? (part 37) William Lane Craig: Thunderf00t's video on Lane Craig's version of the Kalam Cosmological Argument
- ↑ New Apologetics, A Refutation of the Kalām Cosmological Argument, January 26, 2014 
- ↑ 
- ↑ 
- The Journeyman Heretic: On the Kalam Cosmological Argument
-  (TheoreticalBullshit/Scott Clifton's objection to the Cosmological Kalam Argument, and his fallacious responses from William Lane Craig)
- Christopher Alan Bobier, God, Time and the Kalām Cosmological Argument, Sophia, December 2013, Volume 52, Issue 4, pp 593-600