"Now how did that get into our evolutionary mix.....
surely a back up left brain to a left brain
would have served better.....?"
there are features of the human brain which seem to be quite a big leap from other critters.
maybe the sense of space evolves from the 3d aspects of the ape brain. thinking trees. just a preliminary guess.
but to the second point - for me, the opposing forces model creates compromises. and the tension encoded in the compromise is where the higher virtues exist.
if you say - only one hemisphere reflects underlying reality - then you are doing what a dogmatic politician does. you reduce reality to a partisan view. and partisan views are static. they achieve their own perfection. and then stop.
whereas we exist in time, finding ever changing solutions to our ever changing problems. as if we are passing through a mandelbrot set that exhibits resembling patterns while also establishing a balance between both the expanding and contracting forces of chaos.
maybe you are saying the template of chaos is your singularity. that the fabric of reality is rendered in whole cloth. for me, the thing that is absorbing is the pattern rather than the fabric.