Aquinas’ fifth way is known as the Teleological Argument (from the Greek ‘telos’ meaning end or purpose and ‘logos’ meaning ‘to study’). The argument attempts to show that the universe is being directed towards a telos and that there is evidence of intelligent design in the world, which infers the existence of a designer.
Aquinas identified that the way in which 'natural bodies' act in a regular fashion to accomplish their end provides the evidence for the existence of an intelligent being
Aquinas is saying that nothing that lacks intelligence is purposeful without the aid of a ‘guiding hand’ and uses the analogy of the archer to highlight his argument. Just like the arrow (an unintelligent object) requires the guiding hand of an intelligent being (the archer) in order to hit its target (its goal or purpose), so everything in nature which is moving but which has no intelligence must be directed to its goal by God.
A modern version of the argument was devised in the 18th century by Paley in his book ’Natural Theology’. He has two parts to his argument: design qua purpose (the universe was designed to fulfil a purpose) and design qua regularity (the universe behaves according to some order).
Design Qua Purpose
He uses the watch analogy to illustrate the first part of his argument: A man walks across a heath and finds a rock. He attributes the existence of the rock to nature. He walks further still and stumbles across a watch. After some examination, he concludes that its purpose is to measure time. Due to the complexities of the watch, he concludes that it is impossible that the watch had come about without the agency of a ‘watch maker’.
Paley compares the watch to the universe. The universe like the watch is too complex to have just happened by chance and so it is impossible to suppose that the existence of the universe came about without the agency of a ‘universe maker’ – God.
Paley uses the example of the eye to illustrate that there is specific design in the universe. He says that it is obvious that the eye was designed with the specific purpose to see. Thus, Paley argues for a Designing Creator – God.
Design Qua Regularity
The second part of Paley’s argument goes on to suggest that there is further evidence for a creator God in the regularity of the universe. Paley considered the motion of the planets in our solar system. The relationships between the planets, and the effect of gravity could not have come about without a designing principle at work – that is God. I.e. if gravity was slightly stronger or weaker, the universe may not exist today.
J.S. Mills Argument
In ‘Nature and the Utility of Religion’ Mill argues that nature is ‘guilty’ of serious crimes for which she goes unpunished. The ‘atrocities’ through which humans and animals suffer would not go unpunished if they were the result of human agency. “Nearly all the things which men are hanged or imprisoned for doing to one another are nature’s everyday performances.”
Mill concludes that the world cannot have order and rejects that it is the result of intelligent design. Either there is no God or there exists an incompetent or immoral God.
Charles Darwin – proposed the Theory of Natural Selection, which states that the fittest and healthiest members of society survive and their characteristics are passed down. His theory challenges Paley and Aquinas’ argument for intelligent design in the world. He proposes that apparent design is in fact the result of natural and random process. In the words of a geneticist Steve Jones, it is “a series of successful mistakes”.
Richard Dawkins – supported Darwin by saying that random mutations in DNA alone gave rise to variation in the world. Natural selection gave the appearance of design, which led to the mistake of assuming design in the universe.
David Hume’s criticisms
1. An unsound analogy
Hume argued that our world is not like a machine because it is composed of vegetables and animals. It is more organic than it is mechanical.
Characteristics of purpose and design might be obvious in a watch, but they are not nearly so obvious in the world. Indeed, we would only stop and pick up the watch on the heath because it is so unlike the objects which occur in nature.
2. Other possible analogies
Following on from the 1st criticism, Hume said that it would be better to compare the world to a carrot than a machine!
The apparent design in the world could be the result of something similar to generation or vegetation (grows of its own accord).
4. Analogy leads to an immoral God
Hume listed some unpleasant features of nature, for example, earthquakes, war and disease, and questioned how the planning and design could be that of a just and good God.
He claimed that a more plausible hypothesis was that of a God who had no moral character. Alternatively, there could be two forces, one good and one evil.
This principle claims that the universe has been precisely fine tuned to support human life (‘anthropic’ means ‘relating to human beings’). The theologian F.R.Tennant (1866-1957) was the first to coin the phrase ‘the anthropic principle’. By this, he was referring to the way in which the universe seems to be structured so that it was inevitable that life would develop. Below is a list of some of the conditions that have been cited as necessary for the emergence of human beings:
The Big Bang had to occur exactly as it happened, without variation.
There needs to be a precise balance in the values of constants that govern gravitational force and the weak nuclear force in every atom.
A life-containing planet, such as Earth, needs to be at a precise distance from the sun in order to have just enough light and heat to maintain life once it has emerged. There must be the development of self-replicating DNA in the ‘primeval soup’ on the planet.
This argument is closely linked to the anthropic principle and was developed by the modern Christian philosopher of religion, Richard Swinburne. His version of the design argument begins by highlighting the order in the universe and the way that it provides the necessary conditions for life. An example is the laws of the universe (e.g. cause and effect, motion, gravity). These simple laws govern how the world behaves and we use them to predict the future. Furthermore, this is a providential world; one which contains everything necessary for human survival and one in which humans can contribute to its development and maintenance.
Swinburne therefore concludes that an intelligent designer is the best, or most probable, explanation that we have for the universe.