- motion or change
- cause
- contingency
In the First Way, based on motion, Aquinas argued what ever moves is dependant on something else for its motion. The chain of movement cannot go back to infinity and so there must be a first ‘unmoved mover’. This ‘unmoved mover’ is God.
In the Second Way, based on causes, Aquinas asserts that everything in existence must have been caused by something else (things cannot cause themselves as this would mean that they’d have to exist before they existed). Therefore there must be a first ‘uncaused-cause’ to start the chain of causes. This uncaused-cause is God.
In the Third Way, based on contingency, Aquinas observed that things come into existence and later cease to exist. As everything is contingent on something else existing there must have been a time when nothing existed, including the universe. Therefore there had to be a ‘necessary being’ on which every event that occurred afterwards was contingent. This ‘necessary being’ is God.
There were other philosophers who also developed different versions of the cosmological argument.
The Muslim scholars (al-Kindi and later al-Ghazali) developed the ‘kalam argument’ to explain the existence of the universe. William Lane Craig later produced a modern version of the kalam argument which consisted of two parts.
In the first part Craig argued that the universe must be finite as the present exists due to a series of past events. Because all things finite are contingent on something else there must be a first cause of the universe. This first cause is God.
The second part of the argument identifies God as the personal creator of the universe. It observes that as the laws of nature did not exist before the universe was created and therefore the choice must have been made to bring it into existence. Craig asserts that
‘...if the universe began to exist, and if the universe is caused, then the cause of the universe must be a personal being who freely chose to create the world’.
Ed Miller developed another version of the kalam argument in which he observes that there must have been a time when the universe began (if it was infinite there would be an infinite number days and the present would not exist). As events are caused and the beginning of the universe was an event there must be a first cause i.e. God.
The Cosmological Argument is an ‘a posteriori proof’ of God’s existence, i.e. It is based on a set of premises which are drawn from experience but do not necessarily contain the conclusion within the premises.
The fact that the argument is a posteriori has advantages however. It relies on experience which may be universal, or at least testable. It is flexible, i.e. there is more than one possible conclusion and it does not demand that we accept the definitions as fixed. The strengths of the Cosmological Argument lie in both its simplicity and easily comprehensible use of logic. This perhaps provides an explanation as to why, in various forms, philosophers have used it throughout time to demonstrate God’s existence.
One of the most well known critics of the argument was David Hume who asserted the following points:
- The notion of a necessary being is an inconsistent one since there is no being the non existence of which is inconceivable. Even if there was such a being, why should it be God? Hume stated:
‘Any particle of matter, it is said, may be conceived to be annihilated, and any form may be conceived to be altered. Such an annihilation or alteration is not therefore impossible. But it seems a great partiality not to perceive that the same argument extends equally to the Deity, so far as we have any conception of him...’
- Why should the first move/ cause be the God of classical theism?
Here Aquinas is guilty of an inductive leap of logic in moving from the need of a first mover to identifying it as God.
- The argument begins with a concept familiar to us, the universe, but reaches conclusions about things which are outside our experience.
i.e. We do not know enough about the universe to be able to state that it requires an uncaused-cause. And finally
- Why do we need to find a cause for the whole chain if we can explain each item in the chain? Hume wrote:
‘Did I show you the particular causes of each individual in a collection of twenty particles of matter; I should think it very unreasonable should you ask me what was the cause of the hole twenty. This is sufficiently explained in explaining the cause of the parts.’
Even if specific instances of things in the universe require an explanation, why should this be the case for the universe as a whole? Bertrand Russell observed that just because every individual has a mother it does not mean that all humankind has one universal mother.
However the argument’s fatal flaw is that it is inductive. The disadvantages of this are that it relies on accepting the nature of the evidence; it demands overwhelmingly good reasons for accepting that the conclusion is the most likely and finally that; alternative conclusions may be just as convincing.
The Cosmological Argument can be said, on analysis of both its advantages and disadvantages, to have many strengths. It provides fair evidence of the possibility of God’s existence, however by very nature of the fact that it is an a posteriori proof its conclusion is not logically necessary and therefore can always be disproved. Therefore ultimately the Cosmological Argument does not prove God’s existence.
