Third he said that the explanation for the existence of everything in the universe must be external to the universe. If we accept both the second premise, and the theory of Sufficient Reason, then it says that outside the universe there must be a cause for everything inside the universe. He then goes on to say that this explanation must be an existent being which self explanatory is. This, Copleston refers to as a necessary being. If everything within the universe is contingent or dependant, then if we have accepted his ideas, the final explanation must not be necessary. In other words, the final explanation could not not exist. It could not fail to exist; it is not dependant on anything else. This is what Copleston considers to be God.
One other supporting idea for the Cosmological argument is that of the Big Bang theory. The idea that the universe was created by natural causes, such as a large explosion, is considered frequently, but thinkers and philosophers would then argue that the explosion could have been as a result of a divine being, who wished it to happen, and this was simply its way of completing its task.
However, amongst all the supporting theories for the Cosmological argument, and all those who supported it, there are also many critics and conflicting ideologies. Many thinkers have rejected the Cosmological argument.
Firstly, possibly the most influential and studied critic of the Cosmological argument was David Hume. In "Dialogues Concerning Natural Religion" (1779) Hume asked why we must conclude that the universe has to have a beginning. He said:
"How can anything that exists from eternity have a cause, since that relation implies a priority in time, and in a beginning of existence." He went on to say that even if the universe did begin, it does not mean that anything specifically caused it to become. He argued that to make an analogy between the universe and the works of humankind is highly dangerous to the theist since it leads to anthropomorphism. God's qualities are identified so closely with those of humankind in order to make the analogy work that it removes the divine distinctiveness that the believer wants to preserve. (The Cosmological and Teleological arguments - information sheet) He also said that all distinct ideas are separable from each other, and as the ideas of cause and effect are clearly distinct, it is easy for us to conceive any object is non-existent at this moment, and existent the next, without conjoining it to the idea of a cause or a productive principle. The separation therefore of the idea of a cause from that of a beginning of existence is plainly possible for the imagination, and consequently the actual separation of these objects is so far possible that it implies no contradiction or absurdity. By this, he means that we can easily have had a universe without it being caused, as we can imagine something without it actually happening. This was a very strong argument.
Another formidable critic of the Cosmological argument was Anthony Kenny. In "The Five Ways" Kenny pointed out that Aquinas' point about nothing moving itself contradicts the fact that humans and animals move themselves. He used Newton's first law of motion, in which he explains how movement is caused by the body's inertia from previous movement, to disprove Aquinas' theory.
