As a sixth-form Philosophy Teacher I have to teach ‘arguments for the existence of God’. For the most part they are unimpressive and philosophically quite dull. However there is a version of the cosmological argument which, while it falls short of proving God is one that I am consistently impressed by and, to my mind, raises questions which are worthy of attention.
A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn orbits around the centre of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: “What you have told us is rubbish. The world is really a flat plate supported on the back of a giant turtle.” The scientist gave a superior smile before replying, “What is the turtle standing on?” “You’re very clever, young man, very clever,” said the old lady. “But it’s turtles all the way down!” – From Stephen Hawking’s A brief History of Time
Thomas Aquinas has five arguments for the existence of God (his “five ways”). The second way runs as follows:
Premise 1: Every effect has a cause.
Premise 2: Every cause is itself an effect.
Premise 3: The chain of causation (predicated by Premises 1 & 2) cannot go on forever.
Conclusion: There is an uncaused causer, which we call God.
We can reject this argument almost out of hand, by simply pointing out that even if we accepted there is an uncaused causer we don’t need to suppose this is God; we could, for example say that the uncaused cause is the event designated as the ‘big bang’ (though it might be pointed out this is pretty close to Deism).
Having said that there is something persuasive in this argument; I assume that most people will concede the first two premises (though with the caveat that the exact nature of causation
is pretty mysterious – even more so when we try and give it a quantum, and thus probabilistic, structure). In essence though, these two premises seem broadly acceptable.
What is interesting is the third premise; the claim there cannot be an infinite chain of causation. Following the reasoning of the old lady quoted above, is it conceivable that this assertion is wrong and it is ‘turtles all the way down’? There is a notion in philosophy coined by Gottfried Leibniz called The Principle of Sufficient Reason
. Broadly stated it claims that there must be a reason for everything
– ie there are no ‘brute facts’ in the universe – put another way if someone asks me why something exists I cannot respond “it just does” . It seems to me that if we accept this principle then we must concede that Aquinas is correct, there has to be an uncaused cause.
To explain I will refer to the turtle example:
Let us ask the following question:
“What supports the earth?”
The answer, according to our old lady, is:
“A turtle (call it turtle 1)”
I can then ask:
“What supports turtle 1?”
“Another turtle (call it turtle 2)”
To save time we can generate a rule:“Turtle x is supported by turtle x + 1.”
That might seem the end of it but what about the following question:“What supports the whole chain of turtles?”
We have two options here: (a) “nothing supports the chain of turtles – it is infinite and does not require support” or (b) “something else”
If we answer (a), as one supposes the old lady would, then we breach the principle of sufficient reason; we are saying that the chain of turtles is unsupported (ie without reason). To translate this from turtles to causes, we would be saying that the universe is an infinite chain of causation, which has no external reason for its existence. The philosophers David Hume and Bertrand Russell take this view, but it is a disquieting one, it makes the existence of the universe a matter of ‘brute fact’ – the universe simply exists because it does and no further explanation can be given.
What about answer (b)? This will allow us to keep to the Principle of Sufficient Reason – but at what price? If we accept that the chain of turtles is supported by something else (or the chain of causation is caused by something else) then what sort of thing can it be? Well it can’t be a simple thing (like another turtle) because I could add that to my infinite chain and the question is raised again. So if there is something supporting the chain of turtles it itself must be an object which by its very nature requires no support
. In terms of causation what the principle of sufficient reason requires is something which causes the universe, but itself requires no cause - an uncaused causer
. This would be a remarkable result, and one that, not entirely unreasonably, will give much succor to theists. We would be conceding the existence of a unique object which possesses the quality of being uncaused and is responsible for causing everything else. [Note; as mentioned above, I don’t feel any compulsion to identify this ‘uncaused causer’ as God, we could equally well talk of an uncased event like the big bang - but it makes the notion of a 'creator' more plausible than it perhaps seemed before].
This leaves us with two possibilities neither of which I find particularly palatable.
i) The universe is eternal (an infinite chain of causation) and we cannot ever hope to find a reason for it.
ii) The universe has a beginning and thus requires the existence of something unique, an uncaused causer.