The argument for ID is not just the complexity of the eye, it is the information-rich content of the simplest cell of life (before the alleged processes of evolution could start). Any other science, be it the search for extra-terrestrial life, or palaeontology, when discovering code or language assumes without question that an intelligent source is the explanation.
So why are biologists different when they decipher code (of the most complex kind) in a simple cell? Could it be they are starting with the naturalist assumption (for which there could in principle be no evidence) that all physical effects have physical causes.
Biologists can maintain that, one day, they will find a physical explanation for the origin of the code. However at the present time, there is no viable theory about the origin of life (nor about the origin of the universe). However, our pupils are constantly given the impression that all is now understood.
(Lecturer in science and religion)