Filling the Gaps

In order to try and explain what we humans don't understand or don't have enough information to explain, we have invented the dual ideas of  free will and deities; free will to explain what we don't know or don't understand about ourselves, and deities to explain what we don't know or don't understand about everything else.

Complexity Gaps

The irreducible complexity claim by creationists is simply a fancier "god of the gaps" argument that uses a deity to fill the holes in someone's knowledge and/or understanding.