"Theists are impressed, for example, by the fact that the eye is composed of many atoms which work together closely interacting to make possible a particular result - in this case sight. Theists claim that close, complex interaction of countless parts proves that the result produced is actually intended. This assertion is unfounded and an example should suffice as evidence to support my claim.
Consider a random whirl of dust particles. All the particles composing it must interact to produce the exact distribution of particles which occur. If only a single particle has moved contrary to its course, the exact arrangement of particles would have been different. We would never have recognized the change because all dust particles look alike to us, but the result would nevertheless have been different.
Now, according to the theist's reasoning, the existence of this complex interaction of countless particles producing a specific result must indicate the presence of some intention. However, the result of a completely random, totally unplanned whirl of dust particles in exactly what we mean by an unintentional result. Clearly, reasoning which makes a demonstrably unintended result appear to be intended is fundamentally unsound."
B. C. Johnson, The Atheist Debater's Handbook (Amherst, NY: Prometheus Books, 1983), pp. 39-40