He then moves on to state that if everything cannot exist (if everything is contingent), then given infinite time, there will be a time when everything does not exist (a time when there will be nothing). Aquinas has taken ‘can’ from the first statement, added infinite time, and arrived at ‘must’ in the second premise.
His next premise states that if there was once nothing, nothing could come out of it, which leads to the first conclusion of the argument; that something (not necessarily God) must necessarily exist.
This can be considered as the first half of the argument. The next half of the argument attempts to prove that this necessary ‘being’ is what is known as God.
The fifth premise of the argument is that everything is either caused or uncaused. The basis of the next premise is known as the ‘principal of sufficient reason’, which holds, simply, that nothing takes place without a sufficient reason (or, rephrased, without a complete explanation). Hence the next premise states that the series of necessary things cannot go on to infinity, as there would be no sufficient reason.
This leads to the conclusion that there must be some being ‘having of itself its own necessity’, a being that is de re necessary. The ultimate conclusion is that this ‘being’ is what everyone calls God.
Q: What are the strengths and weaknesses of the Cosmological Argument?
There are many weaknesses of the Cosmological Argument as well as some strengths.
The first question that has to be overcome before the Cosmological Argument can be successful (or even applicable), is; ‘why does there have to be a cause for the universe?’ If the answer to this question is ‘ there doesn’t, the universe is just there’, then the argument is useless. However, this is not a weakness in the argument itself and so will not be treated as such.
The first and best strength of the Cosmological argument is that it starts from the seemingly indisputable fact that the universe exists. The argument also follows a logical form, guaranteeing a successful outcome, provided that the premises are true.
However, this is where the strengths of the argument seem to end.
The first apparent weakness of the argument is the first premise; that things can either exist or not exist. As the argument was composed in the thirteenth century, Aquinas would have no knowledge of the ‘conservation of energy theory’, or Einstein’s theory of relativity, both of which state (or imply in the case of the second) that the universe has a fixed amount of energy which can be converted to different forms, but never created or destroyed. Thus if these theories are accepted, the statement ‘things can either exist or not exist’ is only partially correct. For example, when I die, the arrangement and form of the energy (matter) that makes me up will no longer exist, and so in one sense, I will not-exist. However the energy itself will still be in existence. If the first premise is found wrong, the whole argument will be useless.
Another weakness in the argument was proposed by David Hume, who argued that it was illegitimate to move from saying that every event in the universe has a cause, to the conclusion that the universe as a whole has a cause. This criticism was highlighted by an analogy proposed by Bertrand Russell, who remarked that just because every human has a mother doesn’t mean that the human race as a whole has a mother.
A further weakness of the argument is whether or not the principal of sufficient reason is correct or not. Why should it be any more probable that there is a necessary cause than an infinite regression? I do not believe that this question can be answered.
Immanuel Kant also criticised the Cosmological Argument as he held that it is impossible to speculate about something that lives outside space and time when we are confined to the limits of them.
The final criticism that I will mention is the same as I mentioned at he beginning of this essay; that this argument is incapable of arriving at the existence of many peoples conception of God; that at best it can only prove the existence of a necessary being.
The cosmological argument is, in my opinion, incredibly weak. I have only mentioned a few of the arguments against the Cosmological Argument and yet all of the strengths (that I can think of). I believe that the argument is out of date in the light of recent discoveries. However, despite this, considering the lack of knowledge of Aquinas it is of very logical form and may have been far more persuasive at the time.