Statements 1 and 4 in Aquinas' Five Ways seem to contradict each other;
Everything has a cause.
There must be a "first cause".
How can there be a "first cause" if everything needs a cause? A good solution is to reject 1 and accept 4.This argument means there must be a starting point, so does this mean there was a starting point for the "first cause" (God)?Criticism: One can have an infinite regression of numbers so why not in reality? (Hans Reichenbach)Counter: If an infinite regression of causes was possible, then why would there be a sequence of events in the first place?Re-counter: If God is your explanation for why the sequence exists, then what caused God?
Mackie rejects Aquinas' argument that there must be a necessary being.
Why can't it just be a necessary substance?
However, a necessary being and a necessary substance must both be;
- Non physical- Conscious- Possess an ability to create- Intelligent
These similarities suggest that a necessary being and a necessary substance are the same thing.
However, he agreed that infinite regression is impossible, as it is not logical to imagine a train consisting of simply an infinite number of carriages, as there must be an engine to drive it.
If everything has to have a cause in order to exist, then God cannot exist, as he doesn't have a cause.
Therefore, God cannot be the first cause.
The Nature of Causation
Aquinas' claim that everything has a cause is false.
We only can observe that something happened after something else, and cannot conclusively prove that anything caused anything else.
For example, if a superstitious person walked under a ladder and something bad happened afterwards, they would believe it was because they walked under the ladder. However, this is clearly not the case, it was just coincidence that something bad happened after they walked under the ladder.
Hume said that Aquinas' claim that everything has a cause is an assumption, not fact, and so cannot be logically justified.
The Parts and the Whole
Just because all the parts of the universe need a cause to exist, this does not mean that the universe itself needs one.
For example, every living person has a mother, but the entire human race does not have one mother - or so he thinks. Biological researchers have been able to trace the mitochondrial DNA and Y chromosomes of the human population alive today back to one set of parents. It is entirely possible that, whilst the Mitochondrial Eve and Y-Chromosomal Adam weren't the first humans, humans may have descended from the lineage of one male and one female.
Although Aquinas' ideas are valid, it doesn't have to be true.
For instance, there may be more than one 'first mover'. A team of male and female gods who are born and die would fit with our understanding of cause and effect a lot more than the first cause being the Christian God.
Criticisms of Hume
Hume claimed that Aquinas' statement that 'whatever has a beginning of existence must have a cause' is not certain. This means the Cosmological argument could be uncertain.
However, while we cannot necessarily show that every effect is caused by something, believing that everything has a cause is reasonable to everyday life.
Anscombe argued in 1974 that it cannot be logical to think of something coming into existence without a cause. Hume is implying that the universe doesn't need a cause, but this is illogical.
We cannot understand the world outside of our experience of it. We see the world from a limited, human perspective and cannot see it any other way.
As part of this understanding, we experience cause and effect.
However, this does not mean that everything has to experience cause and effect or that everything has a cause, it just means that we can't conceive of any other way of things occurring. (See causality)
God is transcendent, so we cannot legitimately say that God must be caused because the claim goes further than we can understand.
Kant also argues that you cannot use empirical evidence to reach a non-empirical conclusion.
We observe that there is cause and effect in our human level of experience, however this doesn't mean that it is logical to conclude that there exists a necessary being beyond space and time.
Kant dismisses all arguments for the existence of God that try to prove His existence with evidence.
This is because Kant believed in two separate worlds of knowledge; noumenal and phenomenal worlds.
The noumenal world is the world as it truly is without be observed. It is fundamentally unknowable, because the act of observation changes the very thing we observe.
It is as though human beings have a specific set of spectacles that cannot be taken off and like the proverbial rose-tinted ones, they change our perception of the world around us. This personalised view of the universe is the phenomenal world.
Kenny thinks that Newton's Law disproves Aquinas' argument. It is possible for an object to be stationary or moving at a constant rate without any external force acting on it. This appears to prove Aquinas' idea that nothing moves itself as incorrect. The Absurdity of Necessary Existence
J.J.C. Smart says that the Cosmological argument rests on a "thorough absurdity," as necessary existence is incoherent.
Necessity only applies to abstract concepts. The argument claims that there is at least one necessary being, and that things are explicable only by virtue of a necessary being.
A being is not an abstract concept. It is a synthetic concept, not an analytic one. Synthetic concepts are incompatible with necessity.
The assumption that the universe is ultimately explicable is just an assumption without rational justification.
It may be that the universe is simply brute fact; it just is, like Bertrand Russell suggested.
To claim that all that exists must have some total causal and epistemological explanation is unjustified. It is unreasonable to claim that the universe cannot be self-explanatory, when the letter G can be.
Why can't the universe be the necessary thing?
If we apply the principle of Occam's Razor, it seems that this would be the most viable option. So the principle upon which the whole argument is based is philosophically unsound.
Furthermore, if it is explicable, it could be that each thing is explicable on the basis of every other thing, resulting in an infinite regression of explanations. Thus, it is ultimately inconclusive.
Hans Reichenbach demonstrated the logical possibility of infinite regression within the field of math. Therefore, it is possible to have infinite regression of conceptual matters.
However, can infinite regression be factual? It is wrong to claim that is something is logically possible, then it is factually possible.
Energy could be this factual example. It presumably has an infinitely regressive history, and its transfer from one form to another is a causal chain. However, we need to wait for further developments in scientific knowledge for this to be proved or disproved as a relevant example.