I make a finer distinction of "failure" as something that's inefficient for it's clear purpose. E.g. Laryngeal nerve of the giraffe. Evolution will do that on occasion. Sensory interpretations that optical illusions are based on are often optimal for the environment, and are a complement to the power of evolution if anything. Viewing something that is optimal as a failure seems like wishful thinking (though I suspect this is more of a misunderstanding of neurobiology).
Viewing something that is optimal as a failure seems like wishful thinking.
Actually, that seems kind of fair. Something is a "failure to X" if it doesn't achieve X; something is a "failure" if it doesn't achieve some implicit goal. You can rhetorically relabel something a "failure" by changing the context.
Vision works well in our usual habitat, so we should expect it to break down in some corner cases that we can construct: agreed. For me to argue further would be to argue the meaning of "failure" in this context, when I'm pretty sure I actually agree with you on all of the substance of our posts.
Take off every 'quote'! You know what you doing. For great insight. Move 'quote'.
And if you don't: