Shivangi asked:
What makes Cosmological Argument an impure argument?
Answer by Tony Fahey
Hi Shivangi, I take it that when you use the term ‘impure’ you are referring to the fact that the cosmological argument for the existence of God has been found to be fundamentally unsustainable. In the following response I hope to show why this is the case.
The cosmological or causal argument for the existence of God takes the view that there must be a cause either in the sense of a prior event, or a reason for the occurrence of an event. That is, there must be a reason or cause for everything that happens. If we trace back from effects to their causes, we can either continue indefinitely, or reach a point where we are forced to acknowledge that there must be an ultimate or first cause – some point from which everything begins. The cosmological argument is that this first cause is God.
Amongst those philosophers and theologians that make the cosmological argument for the existence of God are Aristotle and Aquinas. Aristotle calls the first cause the ‘Prime Mover’. But it is a prime mover which itself does not move. There is a God, says Aristotle (for how else does motion begin?), but God himself is changeless. He is the final cause of nature, the drive and purpose of things, the form of the world, the principle of life, and the sum of its vital processes and powers – but he does not move.
Aquinas put forward his arguments for the existence of God chiefly in his two main works, the Summa Theologiciae and the Summa contra gentiles. In the Summa Theologiciae he presents his ‘five ways’ to demonstrate the existence of God. The first way is called the argument from motion, which is better understood as ‘change’. It is in this first way that Aquinas follows Aristotle’s ‘prime mover’ thesis. Aquinas begins by claiming that it is evident that some things are in the process of change. Change, or motion, he says, is an observable fact. It is important to say that Aquinas does not say that everything changes, but that some things sometimes change. Aquinas believes that change requires an explanation – a cause. Change, he says, must either come from chance or design, but he rules out the possibility that change is explainable by chance. If change occurs, he concludes, it must be caused.
Following Aristotle, Aquinas concludes that for any change there must be a first principle that causes the change, but which itself is unchanged. This first principle, he claims, is God. God is the cause of change that is not itself changed. This is what everyone understands as god. Therefore God exists.
However, most philosophers (and many theologians) have great difficulty in accepting this cosmological argument. The first difficulty is in the assumption that anything requires a cause. Aquinas rules out the possibility of random or accidental change. Whilst it might be the case that things cause one another, it could still be argued that the cause of events is mere chance and is not connected to a continuous link to a first cause.
The second problem is that we cannot assume that things actually have a first cause. It may well be that things actually do go back ad infinitum.
Thirdly, why should it be that things go back to a single cause? Why can there not be a whole host of different ‘first causes’? it could be that that which causes the physical world to exist is altogether different to that which produces animal life.
Probably one of the most convincing arguments against the cosmological argument comes Immanuel Kant. According to Kant, the cosmological argument is fundamentally flawed (i.e. ‘impure’) in that it works from empirical evidence (our observations of causality) to non-empirical suggestion (that there is a God). Since the conclusion is outside the boundaries of what we know and have observed, we cannot know if our presumptions from empirical evidence can extend beyond those boundaries, so they cannot support the conclusion, which must therefore be erroneous, or ‘impure’. This argument draws the distinction between empirical and non-empirical evidence. As it seems logically sound to postulate that the two cannot be reasonably combined, this is therefore a very compelling objection to Aquinas’ theorem.
A further argument against Aquinas’s cosmological argument is presented by Anthony Kenny in his book The Five Ways. Aquinas, he says, depends for his first argument of causation on Aristotle. According to this analysis, the cause of change must possess a property which will initiate the change. For example, for something to become hot, the thing that causes the change must itself possess the property of heat. But modern science rejects this argument. The grain which makes a cow fat is not itself fat, and microwaves can generate heat without themselves being hot. Aquinas, says Kenny, is not giving a straightforward metaphysical analysis, but an analysis which presumes a classical, and discredited, physics.
Answer by Geoffrey Klempner
I wonder whether Shivangi wasn’t thinking of Kant’s classification, in Critique of Pure Reason between ‘pure’ and ‘impure’ proofs of the existence of God.
The only pure proof — relying on what Kant terms ‘pure reason’, not making any empirical assumptions whatsoever — is the ontological argument.
The cosmological argument, on the other hand, assumes — admittedly something we all know to be the case, otherwise we wouldn’t be here to ask the question — that the world does, in fact, exist. That is why it is ‘impure’. You can’t prove that a world must exist on the basis of the cosmological argument. For that, you need the ontological argument, supplemented with the claim that God, being infinitely perfect and therefore omnipotent and omnibenevolent, would not choose to not create a world.
The teleological argument, or ‘argument from design’, is even more impure than the cosmological argument, if one may talk of degrees of impurity, because it makes the additional empirical assumption that not only does some world exists, but the world that exists exhibits an order and harmony from which one can infer an intelligent creator.
Ask a Philosopher 
You say ” The first difficulty is in the assumption that anything requires a cause. Aquinas rules out the possibility of random or accidental change”
He does not. See Summa Contra GentilesI, ch . 12. Aquinas also never says everything requires a cause. The argument is made on the basis that there are any casual chains at all.