God can't be the Creator because look at all these poorly-designed creatures!  Surely He would have designed them differently!  If God is as smart as He says He is, He never would have done it this way!  For example, in the human eye, the photoreceptors are oriented away from the incoming light and placed behind nerves through which light must pass before reaching the photoreceptors.  This mistake evidences the blind cobbling of evolution, not the masterful hand of God.  

You may have run across this argument before. I have, by well-meaning deist and atheist friends.  This line of thinking is called dysteleology for those who like big words.  The root word is Greek teleos, which means "purpose" or "goal."  The "dys" in front negates that (like "dissatisfation"), so this argument is a positive or forward argument about bad design.

The rest of this blog is an adaption of a response I have written to my friends several months ago.  Upon reflection, it's a good explanation that I feel others may benefit from.

Six reasons why the opening paragraph (dysteleology) simply doesn't work:

1.  Dysteleology is inherently presumptuous:  the invoker presumes to know more than the supposed Creator of the universe. 

2.  Dysteleology is fundamentally a theological argument, not a scientific one.  Rather than arguing with science, the invoker merely reveals their prior choice in the heart against God.

3.  Calling something "broken" implicitly implies a "proper" design by which to judge (but isn't dysteleology meant to argue against design?). It refutes itself.

4.  Calling something "broken" is essentially a science-stopper; the invoker is unwilling to probe further to see if there might be hidden genius in there.  (For example, see Müller cells, which were recently discovered to bend light around the opaque nerves like fiber optics.)

5.  The alternative design is never tested.  If, for example, the eye is poorly designed, a better eye is never created by humans to prove the claim.  Suppose there exists no better design due to unique engineering constraints? 

6.  Most people who use the argument from bad design forget to account for the Biblical creationist clause that biology today is under the Curse and the example may actually be a broken version of what was originally created good. 

For these reasons, whenever I hear my friends use dysteleology, I have some explaining to do.  I can't really blame them, though.  Most people hear something clever from a proponent of their inward position and parrot it.  Unfortunately, in the larger arena of philosophy these days, philosophers have not yet realized the problems with dysteleology.  Some of the repeat invokers, such as Ken Miller, hold Ph.D's and are quite smart.