CATHOLIC ARROW: First, just because we have evolved a certain way does not show that we have to act a certain way—one cannot get an “ought” from what “is.” Secondly, what if the behaviors that we judge to be non-beneficial in an evolutionary sense right now, such as rape or taking the life of an innocent human being, become useful in the future? Perhaps forcing others to reproduce and taking innocent life can become beneficial to the evolutionary process. We intuitively know that this is absurd, but this is fair game in a purely atheistic-naturalistic framework. So, unless an atheist is willing to admit this, then we shouldn’t accept evolution as a sufficient explanation for morality. There must be a transcendent source of goodness outside the natural world—in short, God!
An arrow for the quiver!