The design argument purports to prove the existence of an omniscient, omnipotent, omnibenevolent, and human-like God by analogy. It states that if we look at a creation of humans, such as a watch, house, or computer we can tell that it has a purpose and a designer. If we then look at the world or the universe we can see that it has order, various parts all work in cooperation, and it produces effects. Since the universe appears much like a creation of humans, though much superior and on a much grander scale, the universe must have a designer, who is God.
There are two main assertions in this analogy. The first is that order and functionality imply design; the second that the universe resembles human creations. Both of these assertions are flawed.
First of all, a distinction must be made between function and purpose. Towels, for instance, have the purpose of drying people off. They may be used, however, for many different functions such as a folded as a mat for sitting on the grass, draped over your head to block the sun from your face as you take a nap, wrapped as an emergency bandage, wetted for use in hand to hand combat, etc., etc. None of these functions are the purpose for which the towel was designed, but for someone who knew nothing about towels, they might seem to be the purpose.
Similarly, objects can have function without purpose. If I were to stoop down and pick up a stone I could use it for a number of things. I could crack shells, I could throw it at politicians I don't like, I could carve runes into it, or I could weigh a piece of paper down with it. Was the stone designed for this or any other purpose? No, the stone started as molten rock in the earth. It then changed form by rolling down hills, being washed by rivers, etc. It was not designed, much less does it have a purpose, but it has many functions. In short, we cannot deduce that an object has a designer merely because it performs a function.
Does order imply design? Take the human body, for instance. It has order: the heart, the brain, the blood, the nerves, the bones and muscles all work together in a complex system. Various parts of the whole even have certain functions: the heart provides blood to the rest of the body, the brain tells the body what to do, the stomach digests food to give the body energy, and so on. Yet was the human body designed? No, it evolved, through a long process, from single-celled organisms.
Clouds are another example of objects with order and function, but without design. Clouds certainly have order. Clouds behave in certain ways under certain conditions of temperature and humidity. Clouds have visual order which can be described and distinguished from other types of clouds. They have function: they provide rain and snow, they relieve the heat of a hot summer's day, they give people interesting things to stare at, etc. They do not, however, have purpose. Regardless of whether God designed the process of how clouds are created, individual clouds happen without intention. We cannot accurately predict the presence or the state of a cloud very far in advance. We cannot, for instance, declare that such and such a cloud will have rained some number of times in these places and snowed in those places over a period of a few weeks. Nor can we say, "In three weeks there will be a cumulus cloud right over this spot." This inability for prediction is not due to our lack of meteorological knowledge, it's due to the large number of random