Speculation 1. The bicameral mind was created as a result.
Speculation 2. The earliest creatures with two eyes may have been conjoined twins -- which were more successful in life than their single-celled/bodied siblings.
Speculation 2. The earliest creatures with two eyes may have been conjoined twins -- which were more successful in life than their single-celled/bodied siblings.
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In most cases the evolution of eyes in animals has been from more eyes to fewer (but more complex) eyes, and not the opposite.