Kalam cosmological argument
The aim of this argument is to show that the universe had a beginning in the finite past. The argument battles against the existence of an infinite, temporal regress of past events which implies a universe that has infinitely existed. This argument implies the existence of a First Cause.
The form of the argument is:
1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.
Thomistic cosmological argument
1. What we observe in this universe is contingent (i.e. dependent, or conditional)
2. A sequence of causally related contingent things cannot be infinite
3. The sequence of causally dependent contingent things must be finite
Conclusion: There must be a first cause in the sequence of contingent causes
Leibnizian cosmological argument
The argument comes from a German polymath, Gottfriend Wilhelm Leibniz. Leibniz wrote, "The first question which should rightly be asked is this: why is there something rather than nothing?"
The argument runs as follows:
1. Every existing thing has an explanation of its existence, either in the necessity of its own nature or in an external cause.
2. If the universe has an explanation of its existence, that explanation is God.
3. The universe is an existing thing.
4. Therefore the explanation of the universe is God.
Some atheists object to premise 2 in that God does not have to be the explanation, but that the universe can be what is called a necessary being (one which exists of its own nature and have no external cause). This was a suggestion of David Hume who demanded, "Why may not the material universe be the neccesarily existent being?" (Dialogues Concerning Natural Religion, part 9). The Kalam Cosmological Argument is helpful. If Hume (and other atheists) is right in saying that the universe is a necessary being/thing, then this implies that the universe is eternal. This is exactly what the Kalam argument seeks