The teleological argument

Hello,
You have often mentioned the argument that if one assumes that a work has no creator, then one cannot rely on it.
While we are traveling by train to Scotland, a stone sign suddenly appears with the inscription "Welcome to Scotland." If we assume that it was built intentionally by a builder, then it is very reasonable to refer to the sign and rely on it. However, if we assume that the stones are there by chance and create some kind of inscription, then we should not rely on the information that was formed in them. So far, I am clear, since these are inanimate objects.
We certainly wouldn't rely on an inanimate object (like a clock, an airplane, or an entrance sign to Scotland) that we don't assume was designed and constructed in an intelligent, orderly manner.
What is not clear to me is the leap from not relying on inanimate objects to not relying on a living organ like our eyes (which are also complex and wondrous creations). Our eyes (unlike inanimate objects) are subject to evolution – they may have started from a very primitive starting point and slowly evolved to their complex state today. How does this work out?
thanks