Im not arguing ID over evolution via natural selection..I’m arguing inside the theory of evolution via natural selection..
natural selection cannot favor or if you will select something that is not functional or or used...
you bring up things like colon or appendix which are things that had function in the past so at one point could be naturally selected in the past but now are obsolete ...
that’s fundamentally different than something that has never been used the only way we could have excess capacity of the brain is that at some point in the past it was necessary and used to be selected to be included in our genetic makeup
at least per the logic of natural selection.
Natural selection does not obligate eliminating something with no discernible benefit if there is likewise no discernible harm. If it arises as a fluke, and there’s no harm in it being there, it doesn’t get actively selected out.
As for “excess brain capacity”, the “only 10% used” meme has long been shown/traced as a popular misrepresentation of a more obtuse fact. Dunno about you, but I’m using most of mine.