Sean McDowell | July 14, 2018

Can Atheism Explain Moral "Oughtness"?

Along with my regular blog here at, I am now featuring occasional guest posts from some students in the Biola M.A. in Christian Apologetics that I personally had the privilege of teaching. This post is from my friend Tim Stratton, who has an excellent and growing ministry of his own. Check out his ministry and enjoy this post! - Sean McDowell

Can Atheism Explain Moral "Oughtness"?

Tim Stratton

Are there objective moral truths? This question has major ramifications depending on how you answer it, because it ultimately asks, “DOES GOD EXIST?” We can see the connection through examining the Moral Argument:[1]

1 - If God does not exist, objective moral values and duties do not exist.

2 - Objective moral values and duties exist.

3 - Therefore, God exists.

To avoid this theistic conclusion, atheists must refute at least one of the premises. Many wind up stating that objective moral values and duties do not exist. By making this move, however, atheists affirm that there is nothing really wrong with Hitler’s Holocaust or the Transatlantic Slave Trade. Since rejecting premise (2) tacitly affirms the atrocities of these obvious evils, committed atheists feel the pressure to find another way to ground objective morality. Some atheists, such as Sam Harris, have attempted to find a logical way to ground objective morality in the “science of human flourishing,”[2] stating: “Whatever advances the flourishing of humanity is objectively good and whatever hinders human flourishing is objectively bad.”

Does Human Flourishing Ground Morality?

Harris has failed on several accounts. For instance, even if moral values could be grounded via this “science of human flourishing,” it would be powerless to explain why the flourishing of humans is objectively good. After all, in the movie, The Matrix, Agent Smith referred to the flourishing of humanity as a “virus,” and a “cancer of the planet.”[3] Is Agent Smith objectively wrong, or do we simply have differing subjective opinions? It would be circular reasoning to argue that the flourishing of humanity is objectively good because one assumes it is objectively good when humanity flourishes.

I’ve also heard it said that human flourishing is objectively bad for the earth and all other forms of life. A fellow human exclaimed, “If all insects on earth disappeared, within fifty years all life on earth would end. If all human beings disappeared from the earth, within fifty years all (other) forms of life would flourish.”[4] So perhaps it is bad for humans to flourish, at least from the perspective of “all other forms of life.” The question then becomes, why is it good for humanity to flourish, even if human flourishing hinders other forms of life?

Christianity and Human Flourishing

Atheism cannot answer why the flourishing of humanity is objectively good. All the atheist can do is simply assume it is. Christians do not have this problem. After all, if God exists and created humanity on purpose and for the specific purpose to know, love, and enjoy a relationship with God for eternity, then it is objectively true (independent from human opinion) that it is objectively good (and right) for humanity to flourish.

To make matters worse for the naturalist (the view that only nature exists) this atheistic philosophy is ultimately self-refuting. As a naturalist, Harris holds to “scientific determinism,” which means he believes all of our thoughts and actions are causally determined by natural forces like physics and chemistry. These things are outside of human control. Harris explains:

“Free will is an illusion. Our wills are simply not of our own making. Thoughts and intentions emerge from background causes of which we are unaware and over which we exert no conscious control . . . Either our wills are determined by prior causes and we are not responsible for them, or they are the product of chance and we are not responsible for them.”[5]

Accordingly, if Harris is right about free will being an illusion, then his views on objective morality are nonsensical. This is the case because all human actions would be determined, including actions with supposed moral properties. Harris’ deterministic views undermine his commitment to objective morality.

Science cannot explain moral "oughtness"

Given these objections to the idea of a scientific foundation for objective morality, we must come to the conclusion that science cannot derive an ought from an is, and therefore, cannot tell us anything about how we must conduct our lives in any ethical or moral sense. If naturalistic atheism is true, we have no logical grounds of objective moral values, no logical grounds of objective duty to align our lives with any set of subjective code of ethics, and no ability to do otherwise since all would be determined by outside causal forces.

Since ought implies can, and there seems to be no ability to do otherwise in a cause and effect/determined universe, it follows that it is completely nonsensical for the naturalist to talk about how we ought to think, act, or behave.

Bottom line: If moral values and duties are objective, God must exist!


[1] The Moral Argument:

[2] Sam Harris vs. William Lane Craig debate:

[3] The Matrix,

[4] This quote was attributed to Jonas Salk; however, I cannot find the source. Be that as it may, some people actually believe it is better for insects to flourish than it is for humans to flourish.

[5] Sam Harris, Free Will, (Free Press, New York, 2012), Page 5

Sean McDowell, Ph.D. is a professor of Christian Apologetics at Biola University, a best-selling author, popular speaker, and part-time high school teacher. Follow him on Twitter: @sean_mcdowell, TikTok, Instagram, and his blog: