No its an argument that not everone's structure is exactly the same...thats how evolution works...smh..I am not making this up...go talk to any doctor of medicine or any real scientist of any caliber and they will tell you the same thing.

The foot is designed to preform a large number of functions Thorne, not just the one you mentioned, yes it can kick things and run and walk etc...it cant flap and make you fly though...to do that it would have to have a different overall structure!

As for generalizations about the brain...if the function your trying to preform doesnt have a structure behind it...you simpley wont be able to do it...the brain is designed to do what it does just the way it does it, it hasnt majically changed since we have began delving into it, nor does it show any evidence of having done so in mankinds recent past.

So are carbon atoms...which when pressure is apllied to for a long enough duration and tempurature just so happen to become really dense and become diamond...the atomic structure however is still there yet becuase its arranged differently diamond has different aplications compared to its less dense forms just like any other structure does when its altered..it too takes on different characteristics.

You may find it helpful to try and keep some sence of logic or study up on the subject in more detail if your going to argue from a scientific standpoint with non-lay people.