> I think this is a misuse of the concept of an emergent property. Genes
> are not "one element" that "contributes" to determining the color of a
> child's eyes at birth. They're the *only* element that determines eye
> color. Eye color is not an emergent property determined through the
> interaction of genes and many other underlying factors. It's determined
> solely by genes. Of course, a particular individual's genotype - like
> everything else that is not the Uncaused Cause - is itself the result of
> a chain of historical causation going back to the beginning of the
> universe. But that does not make it an emergent property, otherwise
> everything would be an emergent property.
>
> SA
I have to be blunt: the passage above reflects the fundamental error that I have tried to point out again and again in this thread. Eye color is not "determined solely by genes". The phenotype is determined by the expression of specific instructions under specific environmental conditions. The same genetic instructions can lead to different phenotypes, depending on the environment in which the genetic instructions are expressed. This is true of all phenotypic characteristics, including eye color.
I have to stress again that I'm making a straightforward point about genetic transmission that is covered in any introductory genetics course.
Miles