Aug 22, 2017 · 1 min read
An addition:
Some external behavior, bias or trait might not be directly beneficial, but might be a necessary byproduct of a trait whose other byproducts are beneficial to survival.
For example, I suspect it’s the case of some autoimmune diseases.
As another example, seeing imaginary faces in clouds isn’t beneficial, but a man who’s able to see faces in clouds is also able to spot a predator in the forest (can’t reduce false positives without increasing false negatives).
