The design argument, also known as the argument of teleology, is the argument for the existence of God, or some kind of intelligent creator. Derived from the Greek word ‘telos’ meaning end or purpose, it is an a posteriori argument, because it is based on experience, not on reason or revelation, using the surroundings of the world as supporting evidence. The argument is an inductive one, as its reasoning can give way to many conclusions, and because it is based on experience it is measurable and artificial. There are two main arguments that philosophers have used for Design, qua (relating to) regularity and qua purpose.
Saint Thomas Aquinas, (1225 – 1274) famously wrote ‘Summa Theologica’, in which he presented five ways to prove the existence of God. In his fifth and final argument, he states that natural things work towards some goal and most natural things lack knowledge, but as an arrow reaches its target because it is directed by an archer, what lacks intelligence achieves goals by being directed by something intelligent. Aquinas says that the archer, or the director, is God. Another example used by Aquinas to prove his argument was the fact that whales migrated thousands of miles to a suitable location in which they can breed. This is the main strength of the argument is because it is factual and observational, and based on our senses in the world, which makes it understandable and coherent to everyone.
William Paley (1743 – 1805) presented the most famous argument for design, qua purpose, in his book ‘Natural Theology’. He presented his argument in the form of a simple analogy. If we were to come across a watch, we would say that the complex mechanisms within the watch had not come about by chance, but instead from a designer. In the same way, if we observe the world we can say that there is a designer, because of the intricacy and complexity of the way that things fit