A posteriori. The design argument and cosmological arguments are a posteriori arguments, which means they are based on experience. The design argument is based on the observation of particular aspects of the universe which, it claims, have the appearance of design. The cosmological argument is based on observation of everything in the universe being contingent and therefore requiring a creator which is necessary. These observations form the premises of the design and cosmological arguments. On the basis of those observations, an inference is then made to the nature of the origin of the universe.
Inductive. These arguments are called inductive arguments, which means they have premises which give evidence for, and support to, a conclusion. The truth of the premises does not logically entail the conclusion. So, inductive arguments are those for which their premises could be true and yet their conclusion false. They give us reasons for accepting a conclusion, though cannot prove that the conclusion is certain. The best an inductive argument can achieve is to show that a conclusion is what we currently have most reason to believe based on our best attempt to understand the available evidence.
Inductive arguments as proofs. Evidence is not proof. The reason for this is that arguing on the basis of evidence cannot guarantee truth, because for all we can currently know there is additional evidence we could discover that would disprove the conclusion our current evidence suggests. The technical term for this is that knowledge based on experience is ‘defeasible’, meaning it could be wrong because we don’t know everything.
Aquinas’ 5th way
Aquinas observed that things in the world moved towards a certain goal or purpose that was beyond their own ability to comprehend. Therefore ‘a designer’ is required to explain that.
Metaphor of archer and arrow: An arrow hits a target even though it isn’t sentient and cannot comprehend what it’s doing. There must be something which can comprehend the direction of the arrow: the archer (who is sentient) shot the arrow.
Similarly: Things in the natural world follow natural laws but are not sentient or not sentient enough in the case of animals, to dictate their own behaviour. Therefore, there must be an archer for the arrow of the universe, which must be a God.
Aquinas’ Fifth Way – Design qua regularity:
P1: The behaviour of objects is regular and predictable because they follow natural laws.
P2: These natural laws cannot have been created by the objects themselves since they are non-intelligent or insufficiently intelligent.
C1: The natural laws must have an intelligent designer. That thing we call God.
William Paley’s design argument
Design qua Purpose is Paley’s argument that the combination of complexity and purpose are best explained by a designer.
Paley illustrates this with the example of a watch. If you were walking on a heath and came across a watch, you couldn’t argue it had come about by chance nor been there forever because it has Complexity & Purpose. This must mean it had a designer – a watch maker. Paley then points out there are also things in the universe that are complex and have a purpose. He points out in particular the complexity of the Human eye which is arranged to fulfil the purpose of enabling us to see. He also points to the wings of a bird and fins of a fish which are examples of complexity fitted together to perform a purpose of flying and swimming.
“Every manifestation of design, which existed in the watch, exists in the works of nature.”
Since complexity and purpose in a watch tells us there must have been a watch making, similarly the complexity and purpose in the universe tells us that there must have been a universe maker: God.
Design qua Regularity is another type of design argument made by Paley which draws on the observation of the order found in Newtonian physics. Paley pointed to the rotations of planets in the solar system and how they obey the same universal laws as shown by Newton’s laws of motion and gravity. Paley argued that unless gravity consistently has the strength it does within a narrow boundary, then the planets would be unable to maintain their order and life on earth could not exist. Similarly, why is the universe regular and not chaotic? This could not have come about by chance.
David Hume’s critiques of the design argument
Hume’s evidential problem of evil
Hume aims to show that a posteriori observation of the world cannot provide a basis to conclude that a perfect God exists because the world contains imperfections like evil. Hume isn’t trying to prove that there is no designer, just that a posteriori evidence cannot be used to show that the designer must be the God of classical theism (omniscient, omnibenevolent, omnipotent).
‘I … allow, that the bad appearances, notwithstanding all my reasonings, may be compatible with such attributes as you suppose: But surely they can never prove these attributes’
Hume, as an empiricist, insists that we are only justified in believing what the evidence suggests. The evidence of an imperfect world, while logically compatible with a perfect God, can never justify belief in a perfect God.
Paley responds that even a broken watch must have a watch maker, and so too must it be with the universe.
Alternative response to Hume’s evidential problem of evil: theodicies.
Hume’s criticism of the use of analogy
Hume argues that it doesn’t follow from the similarity of two effects that they must have had similar causes. For example, the smoke produced by fire and dry ice is very similar, but their causes not similar. So, just because the effect of the universe and the effect of a a man-made thing like a house (Hume’s example) or a watch are like each other in that they both have complexity and purpose, it doesn’t follow that the cause of the universe must be like the cause of a house/watch i.e., a designer. Two effects which are alike (analogous) might in fact have very different causes.
Hume highlights this by pointing to our utter ignorance of the state of nature during the beginning of the universe:
“Can you claim to show any such similarity between the structure of a house and the generation of a universe? Have you ever seen nature in a situation that resembles the first arrangement of the elements ·at the beginning of the universe·?” – Hume.
Even if we could claim an analogy between natural things and man-made things, for all we know there may be no analogy between their origin.
Hume argues further that we can’t even claim analogy between artefacts and natural objects. Artifacts are mechanical, but the universe appears more organic.
Paley’s argument is arguably not based on an analogy. Modern philosophers tend to read Paley’s argument as not being based on an analogy between artefacts and the universe. His argument is that there is a property which requires a designer; the property of complexity and purpose – parts fitted together in a complex way to perform a purpose. When a complex of individually complex parts are fitted together in a meticulous way so as to achieve an overall function/purpose, it seems almost impossible for that to have come about by pure chance. A better explanation is a designing mind. Man-made things have this property but so too do natural things like the eye. Therefore, nature requires a designer because it has this property, not because of any analogy to man-made things. The watch is merely an illustration. We know the universe is designed because it has complexity and purpose.
Hume: the teleological argument is arguing from a unique case
Hume challenges the idea that we could possibly know that complexity and purpose must be caused by a designer in the case of the universe. He contends that inferring the existence of one thing from the existence of another thing requires experience of their constant conjunction. It follows that if we want to infer a designer from an object, we need experience of that object being made by that designer. For example, in the case of a house, justifiably inferring a designer requires experience of houses being made. Yet, regarding the universe, we clearly do not have such experience.
“But it is hard to see how this pattern of argument can be appropriate in our present case, where the objects we are considering don’t fall into sorts, but are single, individual, without parallel or specific resemblance.“
All we experience is the universe itself, not the origin of the universe, not any creator conjoined with it. We have one unique case and no basis on which to infer anything about its origin.
“To make this reasoning secure, we would need to have had experience of the origins of worlds”
Hume concludes that the origin of the universe, “exceeds all human reason and enquiry.” So, Hume concludes that we lack the required experience to justify inferring the existence of a God from the existence of our world. The only rational thing to do in such cases is to suspend judgement.
“A very small part of this great system, during a very short time, is very imperfectly discovered to us; and do we thence pronounce decisively concerning the origin of the whole?” – Hume.
Hume’s argument doesn’t apply to the watch. Paley’s argument rests on the premise that we know a watch is designed by its complexity and purpose. Arguably a person could come across a watch and would know it was designed, even if they had never seen watching being made or even heard of how they were made. So, it looks like Paley is right that someone can know something is designed by its complexity and purpose, and that Hume is wrong to think that experience of the causal process that originated it is required to know whether it was designed.
Actually it does. However, Hume’s point is that even if someone got the correct idea that a thing is designed by observing its complexity and purpose, they actually don’t have justified knowledge. It’s possible for someone to get a correct idea through unjustified means. Paley could even be right that complexity and purpose is the feature of the watch that tempts us to the conclusion that it was designed, but that doesn’t justify the belief that the watch was designed. Even though the belief be true, it may be false for anything they know, because they lack justification. The only way to know a watch is designed is to see it being made.
Hume: God is not the only explanation
Hume argues that even if we had evidence of design in the universe, that would not support the claim that it was designed by the God of classical theism. It could have been made by a junior God, apprentice God – or even a God who died. There could be multiple designers – ‘a committee of Gods’. So, the design argument doesn’t even justify monotheism.
Swinburne claims that Hume’s points here are correct and that the design argument cannot prove that the designer has the attributes of the God of classical theism. Other arguments will be needed for that.
However, Swinburne thinks that Ockham’s razor can be used against some of Hume’s claims here. One God being responsible for the design of the universe is a simpler explanation than multiple. Swinburne also points to the uniformity of the laws of physics as suggesting a single designer.
Hume’s Epicurean hypothesis
Epicures was an ancient Greek philosopher who thought the universe was had existed infinitely and was composed of atoms. Hume pointed out that if Epicures was correct, then a chaotic random universe, given an infinite amount of time, will by complete chance occasionally assemble itself into an orderly one. The atoms will happen to collide in such a way that an orderly arrangement of them will come about. On an infinite time scale, if something can possibly happen then no matter how low the probability, it becomes 100% guaranteed to happen. Not just once, but an infinite number of times! For example if monkeys were randomly banging away on typewriters for an infinite amount of time, then they would produce the entire works of Shakespeare. Similarly, a chaotic universe of randomly moving and fluctuating objects will happen to coalesce into an orderly arrangement given an infinite time frame.
The current scientific view is that time began at the big bang, however. Therefore there has not been an infinite amount of time.
However, perhaps there were infinite universes before ours or an infinite number of universes (multiverse theory). Rather than a regular universe occurring by chance due to an infinite time-frame, instead it could be that a regular universe occurred by chance due to there being an infinite number of every type (regular and chaotic) of universe.
Swinburne’s response: however, there is very little evidence for the multiverse theory. Polkinghorne agrees and claims that the multiverse theory is a ‘bold speculation’, a ‘metaphysical guess’.
Modern design arguments after Darwin
Darwin’s theory of evolution by the process of natural selection showed that order in nature was not necessarily evidence of purpose and design but could instead be explained by natural means. This suggests that proponents of the design argument are wrong to think that purposeful features of animals must have been created by a designer.
F. R. Tennent
Tennent made two main arguments which paved the way that most defenders of the design argument went in after Darwin. Tennant accepted the scientific evidence for evolution but argued that humans had features that evolution without God could not explain (aesthetic principle) and that for evolution itself to be possible presupposes an extraordinarily unlikely level of order (anthropic principle) which is better explained by a God than by chance.
Tennent’s aesthetic principle suggests that evolution could not have produced humans without God’s interference with evolution. How can Darwinian evolution explain our perception of beauty? It doesn’t give us a survival advantage, yet it evolved. Only God controlling evolution can explain this.
Dawkins’ criticism of Tennent: perception of beauty makes animals more attractive to their mate which results in more offspring, which is good for survival.
Defence of Tennent: sexual attractiveness doesn’t seem to be all there is to beauty, what about music, literature, nature.
Counter-defence: The evolution of the perception of beauty could simply be a biproduct of the evolution of intelligence
Tennent’s anthropic principle. Tennant points out that this universe being hospitable to living beings requires a “unique assembly of unique properties” on a “vast” scale, including “astronomical, thermal, chemical, and so on”. Our universe has to be orderly and the order must be of a particular kind in order for evolution to have been possible and thus for us to exist. This suggests that our planet has been specially designed for human life to be possible.
However, it started to become clear that although the conditions on earth were very precise, given how large the universe is and how many planets there are in it, we should expect there to be many earth like planets completely by chance. No special kind of explanation like design is necessary. In our galaxy alone there are 100 billion planets.
The anthropic fine-tuning argument
More recent philosophers have used newer scientific discoveries in adding to Tennant’s argument, which today is referred to as the anthropic fine-tuning argument. Instead of focusing on the orderly arrangement of matter on our planet, it claims design can be inferred from the laws of nature/physics.
This argument is put forward by philosophers such as Swinburne and Polkinghorne. It is based on an observation that the laws of physics seem to be exactly how they would need to be for life to be possible. If the laws of our universe, such as the charge of the electron, were a tiny degree greater or lesser, life could not exist at all. It is unimaginably unlikely for it to be by chance that the physical laws have the variables they do to the degree of precision required for our existence to be possible.
The argument then claims that this is not something science can explain. Science tells us the what but not the why. For example, science can tell us that E=MC2, but it cannot tell us why E-MC2. Science can only discover the laws of nature but cannot tell us why there are laws which means it cannot tell us why the laws are fine-tuned for life. Science cannot even explain why the universe can even be understood by science at all. The best explanation of the fine-tuning of the universe is God.
Multiverse theory: Max Tegmark, a physicist, suggests a scientific explanation of fine tuning. The multiverse theory suggests our universe is just one of an infinite number of universes, all of which have different laws of physics. So, the fact that some universes are so perfectly fine tuned for human existence doesn’t require any special explanation, since there are an infinite number of every possible configuration of universes.
Swinburne’s defence: However, there is very little evidence for the multiverse theory. Polkinghorne agrees and claims that the multiverse theory is a ‘bold speculation’, a ‘metaphysical guess’.
Fecundity. Tegmark also puts forward the argument of fecundity, which is that although human life might not be possible with different laws of nature, other forms of life could be possible. So there is no fine-tuning because intelligent life could arise in many forms in many different types of universes.
Anthropic fine tuning makes assumptions about what a non-designed the universe is like. The fine-tuning argument claims that it’s unimaginably unlikely that fine tuning happened by chance. But this seems to assume that were it not for the efforts of a God, the ‘default’ state of nature would not be fine tuned. But how could we know that? How could we know the ‘default’ or non-designed state of a universe? That seems to assume that a universe which is created by chance does something like roll some dice to figure out what its laws will be, but that might not be how it works at all. The claim that a universe with the physical laws ours has is ‘fine-tuned’ is only valid if we know what a universe which is not fine-tuned were like. The claim that it would likely be chaotic and random is merely an assumption. To really know that a universe is designed or fine-tuned, we would have to compare it to non-designed universes or see the universe’s creation, as Hume argued.
Possible exam questions for the Teleological argument
You could be asked to assess/evaluate:
- Whether a posteriori or a priori is the more persuasive style of argument.
- Whether teleological arguments can be defended against the challenge of ‘chance’.
- Whether or not there are logical fallacies in these arguments that cannot be overcome.
- Whether the teleological argument is successful, convincing, persuasive.
- Aquinas’ Fifth way.
- Hume’s criticisms of the teleological argument
- The challenge of evolution.