William Craig supports the Kalam argument by claiming that the universe has a beginning.
Craig uses the thought experiment of "Hilbert's hotel" to show that disputing the beginning of the universe creates a paradox.
Hilbert's hotel demonstrates that infinity can lead to a paradox, where people can arrive and leave the hotel without changing the number of rooms, and yet the hotel is still full.
If the universe has existed for an infinite amount of time, it would mean that the universe does not age as time passes, and this is a contradiction.
Therefore, Craig argues that the universe must have had a beginning, and the Kalam argument follows from this.
The argument assumes that if all beings in the universe are contingent, then nothing would exist now.
However, it is possible to argue that an infinite chain of contingent beings could exist.
The argument does not provide sufficient justification for why an infinite chain of contingent beings cannot exist.
This raises questions about the validity of P2 and P4 in the argument
Does the principle work for all facts? At the quantum level, explanations may not be available for human minds.
How detailed does a sufficient reason need to be? For a chemist, the explanation of chemical reactions may be enough, why go back to a necessary being?
Infinity can come in different sizes of "sets"
The set of even numbers is twice the size of the set of all whole numbers
Cantor's argument challenges the notion that infinity is a single, uniform entity
Craig argues that Hilbert's hotel creates a paradox, as infinity + 1 = infinity and infinity + infinity = infinity cannot both be true
However, if Cantor is correct, then these paradoxes disappear
Therefore, the possibility of an infinite series challenges the validity of Hilbert's hotel argument.
Aquinas argues that a chain of events without a first cause is logically impossible
However, Hume argues that an infinite chain of causation does not require a first cause
Aquinas' argument applies to finite chains, but not necessarily to an infinite chain
Hume claims that we cannot logically reason whether the chain is infinite or not, as causation is not a relation of ideas
Craig argues that the Big Bang theory supports his version of the Kalam argument
Craig believes that the Big Bang suggests that the universe has a beginning and anything that has a beginning has a cause
Craig argues that the cause of the universe must be external to the laws of the universe, and is personal, all-powerful, and non-corporeal
Craig concludes that the cause of the universe is what we would call "God"
However, the Big Bang/Big Crunch hypothesis and the multiverse hypothesis could undermine Craig's claim
The Big Crunch hypothesis suggests that the Big Bang arose from the collapse of another universe, part of an infinite chain of universes expanding and collapsing
Many multiverse models assume infinite universes, and infinite time or space
The causal principle states that every effect has a cause
Without the causal principle, cosmological arguments cannot deductively prove the universe has a cause
Hume believes the causal principle is not a relation of ideas and is not deductively or logically certain
Hume thinks that understanding the link between cause and effect comes from observing the same effect following the same cause multiple times
Hume believes that causation is a matter of probability, not certainty, and therefore cannot be used in deductive arguments
Russell's objection to the cosmological argument:
The cosmological argument commits the fallacy of composition.
Russell gives an example to illustrate the fallacy of composition, stating that every man has a mother, but that doesn't mean that the human race has a mother.
The same logic is used in the PSR, which says that every event/truth requires an explanation, but it doesn't lead to the conclusion that the universe as a whole requires an explanation.
Russell suggests that we accept that the universe is just there, and that's all.
Aquinas' third way:
Aquinas argues that if the universe was only made up of contingent beings, then there must be nothing at all at some point.
This also commits the fallacy of composition.
Aquinas gives an example of five Canadians on a street corner in New York, where each tells us their own parts of the world are caused, but we wouldn't demand a further reason that all five are there as a whole.
In the same way, we can explain how individual parts of the world are caused, so why do we need a further explanation for the whole thing?
Avoiding the objection:
The fallacy of composition is not always wrong.
There may be examples where arguing from the part to the whole is correct, such as how the universe is constructed of atoms
Hume and Russell's objections assume that "God exists necessarily" means the sentence 'God exists' is necessarily true.
However, many people define necessary existence as "depending on nothing else to exist."
This definition does not contradict the statement "if God exists, God exists necessarily."
Hume and Russell's arguments do not give us reason to reject this definition of necessary existence.
The cosmological argument from contingency leaves us with a dilemma: either the universe is explained by a necessary being, or it is not explained at all.