Atheists will argue that there does not need to be a God given moral law, but that we can choose to do anything so long as we are not hurting someone.

For example, as long as sexual activity is between consenting adults, you should be free to do whatever you like, with whomever you like, in whatever combinations you like, and in whatever circumstances you like in or out of marriage as long as no one is hurt by it. ‘Hurt’ is usually narrowly defined in terms of sexually transmitted diseases or pregnancy.

If human beings are nothing but highly evolved animals, as atheists claim, then it could be argued that no harm is done when people behave like animals. A hedonistic lifestyle may adequately provide for what you want out of life. Do whatever your desires and appetites and addictions and fetishes compel you to do.

If God exists, and he designed human sexuality to be expressed and find its meaning and fulfillment in the loving commitment of marriage, then unbridled sexual activity would be a destructive activity that attacks human dignity and eventually inflicts profound and lasting emotional, spiritual and physical wounds.

Everyone is hurt by the ‘do no harm’ ethic. Those involved in sexual promiscuity, or in other immoral activities that might be considered entirely private, are hurt because God made them for something so much higher and better. They degrade themselves when they fail to pursue their higher calling. Those who follow their example are hurt, especially the children who assume that this must be a good way to live. Parents who would never have wanted this for their sons or daughters are hurt. Even society itself is hurt as its moral tenor is diminished by such behavior even though its proponents claim they’re not hurting anyone else.

A problem for the naturalist who subscribes to the ‘do no harm’ ethical standard is that it is actually inconsistent with the naturalist worldview. Do naturalists see the ‘do no harm’ standard existing in nature? Is this something the natural world teaches us? Didn’t Darwin claim that, in nature, the strong prey upon the weak and only the fittest survive? Isn’t his how things should be in this strictly material world?

If human beings are merely highly evolved animals, why is it universally understood to be wrong for one human being to steal from, injure, or murder another human being? What is the rational basis to insert the notion of ‘right and wrong’ into an atheist worldview?

The consistent atheist is forced to admit that the ‘do no harm’ standard contradicts the naturalist worldview that embraces Darwin’s evolutionary principle of ‘survival of the fittest’. Natural selection is guaranteed not be being nice to competitors but by overpowering weaker competitors.

From “The Godless Delusion” by Patrick Madrid and Kenneth Hensley.