Many philosophers have contributed to the design argument with their own understanding of it and their own ways of explaining it. These philosophers all agree that there is an order, purpose and regularity in the whole universe, this is what we also learn from science. For example the heart in our body shows it has order, certainly a purpose and it works regularly. The oxygenated blood is send to the body from the heart by the arteries and the deoxygenated blood is send to the heart from the body by the veins and its purpose is to keep us alive by sending oxygen to every cell in our body for respiration and it works regularly as the heart contradictions occur at about 72 beats per minute.
Paley offered us an analogy to try to explain the argument. He put it to us that if we were to find a stone on the ground, and were asked why it was there, we would think it had laid there forever. However, if we were to find a watch on the ground, and were asked the same question, we would reply that it was there because somebody had designed it. Paley says that the stone on the ground is no different to the watch, as each as been designed. The stone, and more widely speaking, the whole universe has been designed by a "Great Architect": God.
St Thomas Aquinas believed that "some intelligent being exists by whom all natural things are directed to their end; and this being we call God." He stated that anything that lacks knowledge cannot move towards an end but must be directed towards that end by God. Aquinas is arguing from the design qua regularity point of view.
Another philosopher who contributed to this argument is F. R. Tennant. He contrived the "Aesthetic Argument." This declares that the appreciation of beauty, art, and poetry are not necessary for the survival of humanity or the development of life. Therefore man is not simply a product of evolution and natural selection but a specific design. Simply put, he says the fact that the universe is saturated with beauty suggests that it can't just have happened- there must have been a designer- again, God.
The Anthropic Principle, again developed by Tennant, is a more scientific method of supporting the design argument. The conditions of chemicals and gasses at the time of creation where in just the right proportions for the development of human life. If these values had been even just a tiny bit different then this would not have been possible. With this in mind we are encouraged to conclude that, with such a minute chance, surely the universe must have been designed.
There are weaknesses in the design argument that can be expressed. The basis of the argument "There is order in the universes, the universe has been designed, God has designed the universe" is an a posteriori argument. The universe certainly isn't ordered in the same perfect way as a watch is ordered. This shows Paley's analogy to be flawed. For example how can the world be in a state of perfect order when we have what is called "natural evil" in the world. Is nature not sometimes chaotic, not ordered? How does the design argument explain earthquakes and other natural disasters? We are told that God is benevolent, omnipotent and omniscient. If God created nature in such an ordered and perfect way, then why would he allow these aspects of it into his "divine plan"? The "Epicurean Hypothesis" argues that the universe began as chaotic but gradually became ordered as it stabilized. (Chemistry tells us that all elements "want" to become more stable. That is why they react together if they are unstable or volatile.) Therefore stability and order are nothing to do with God at all but simply scientific fact.
Some philosophers do agree that the world has order and regularity but simply don’t believe that God is the one who designed the universe, which is similar to the way of science. A criticism of the design argument, put forward by David Hume, is that humans do not have enough knowledge to recognize that there is only one designer. In fact there could have been many Gods or designers that created the universe. To explain this theory he uses the analogy of manufactured objects. Machines are usually designed by a team of designers working together, not just one designer.
Immanuel Kant also challenges the foundations of the argument. The argument presupposes that there is regularity, order and purpose in the universe. Kant emphasises the fact that the universe may be in utter chaos but, because of the way our minds organise our experiences, the world around us appears to be ordered, but we impose the design on the world ourselves, and cannot be certain of the reality of the situation. Possibly we could compare our world or our universe to another and then discover the truth of the situation. However, this is seemingly impossible. Using this argument, which cannot ever be disproved, we bring the discussion back into the realms on non-realism, in which there are no absolutes beyond our own perception.
Richard Dawkins disagrees with the fundamental principle of the argument that the universe has a designer. He reduces it to science, by arguing that any variations in the universe are caused by random mistakes in the DNA.
Despite these many flaws in the argument, it still has many strengths. The Telelogical Argument was described by Immanuel Kent as the oldest, clearest, and most reasonable argument for the existence of God even though he himself admitted to finding it personally unconvincing. Part of the argument's strength lies in its simplicity. It is easy to relate to the argument as humans are themselves designers by nature. It is natural for humans to think of things as having a purpose.
The argument also makes good use of analogy. Whether this is using a watch, television or an acorn, using concrete images to explain abstract ideas aids our understanding of the argument by placing it within a context that can be easily understood.
Some have also cited the argument's strength comes from its relation with religious materials, for example the creation story. "In the beginning God created the heavens and the earth." For believers in God, this confirms and cements their beliefs.
In conclusion, the success of the Design Argument rests upon probability and individual judgment. The Design Argument, as illustrated by the various criticisms of it, is by no means conclusive, if it was then everyone would know that God exists. If you believe that the universe is a product of blind chance then the design argument will not be strong enough to change your beliefs. I.e. it won't convince an atheist. However, the idea of the universe just being here, a brute fact, a product of blind chance and nothing more is a personally unsatisfactory one due to the extraordinary nature of the universe and so whist the Design Argument may not conclusively prove the existence of God it suggests that the existence of a Designer, who we know as God, is a more probable likelihood than not.
Science shows the design of the universe. Science strengthens the design argument as it shows us more and more information about the universe. Therefore there is even more reason for believing that there was and is a designer who planned and created the universe. But there is no proof that the designer is God.
