This is not a good analogy, because both kidneys do the same thing and we don't need both of them to live.
Whereas the left and right brain hemispheres do different things that enable our species to be what it now is; which is more similar to what the article calls hind and fore/front brains, which again do different things that we wouldn't be us without. We would still be human if we had only one kidney the way we have only one bladder or one pancreas.
Kidneys are more like say lungs, gonads, breasts, or nostrils in that we have +1 extra; but the benefit created by multiplicity is ~doubling or capacity and resilience to local disease and random injury-- not a profound functionality. (Like is created by the second eye or second leg.) Of these, the second breast is radically more useful than the second kidney, and is probably a special case as it changes how we live so evolved.
alt Hacker News
This is not a good analogy, because both kidneys do the same thing and we don't need both of them to live.
Whereas the left and right brain hemispheres do different things that enable our species to be what it now is; which is more similar to what the article calls hind and fore/front brains, which again do different things that we wouldn't be us without. We would still be human if we had only one kidney the way we have only one bladder or one pancreas.
Kidneys are more like say lungs, gonads, breasts, or nostrils in that we have +1 extra; but the benefit created by multiplicity is ~doubling or capacity and resilience to local disease and random injury-- not a profound functionality. (Like is created by the second eye or second leg.) Of these, the second breast is radically more useful than the second kidney, and is probably a special case as it changes how we live so evolved.