Outlining an Evolutionary Argument Against Moral Realism, On Materialistic Atheism


In a recent article on The Stream that’s proved controversial among some Christians on Facebook, I argued that gay activists who adhere to materialistic atheism cannot claim that homosexuality is really good. Part of the controversy I’ve faced has to do with the evolutionary argument I summarized there, suggesting that moral realism is impossible on materialistic atheism. At least one person on Facebook has called it a weak argument few philosophers would endorse.

Now, on the one hand that’s not surprising. It was a Stream column, not a philosophical treatise, so I didn’t lay out the entire argument. On the other hand, though, if the argument really fails, then I really want to know it. So here today I’m expanding the outline. Yes, it’s still in outline form, but with the steps filled in.

The primary point I’d want to make is under A, B, and C below: Moral realism is impossible on materialistic atheism, because in order for real right and wrong to exist, they would have had to come into being at some point, and materialistic atheism offers no sufficient cause for their beginning to exist.

By moral realism, I mean that some entities, actions, intentions, and outcomes are inherently good (good in themselves), others inherently bad (bad in themselves); and that they have these values with or without any human judgment agreeing or disagreeing with those values.

Part D presents a secondary conclusion: That words like “right” and “wrong” have no meaning or function except as labeling behaviors supporting human populations’ survival and reproduction. They are, in fact, nothing but labeling behaviors that serve that evolutionary purpose.

What follows here is my very unpolished, draft outline of the argument, published for your comments.

Given materialistic atheism:

A. The Genesis of Real Right and Real Wrong

  1. Nothing exists except the material world of matter, energy, and their interactions in accordance with natural law.
  2. Causation is closed: There are no effects but those which can be traced to material causes.
  3. Moral evaluations such as “right” and “wrong” could not have meaningfully existed prior to the evolutionary arrival of sentient beings. It’s literally nonsense to suppose that any event or effect could have been either right or wrong, in deep evolutionary history, much less in the eternal past.
  4. Having been previously nonexistent, real right and real wrong could not exist today unless they began somehow to exist. (See comment 1.)
  5. Some sufficient cause is necessary in order for real right and wrong to begin to exist.

B. The Locus of Right and Wrong

  1. Right and wrong (whether subjective or objective) have meaning only in relation to sentient beings.
  2. The existence of sentient beings is ultimately explained by matter and energy interacting according to natural law, and nothing but that.
  3. More proximately, the existence, form, and behaviors of sentient beings are fully explained through neo-Darwinian processes of random variation and natural selection.
  4. Therefore right and wrong exist only in relation to sentient beings, and only as a product of random variation and natural selection.

C. Evolutionary Processes, Causal Closure, and Moral Realism

  1. Random variation happens strictly in the realm of biochemistry, and biochemistry does not have the causal resources to cause rightness or wrongness to begin to exist. Therefore random variation is not the sufficient cause, required per A.5.
  2. Natural selection selects for, and metaphorically produces or creates, adaptive biological and behavioral features and functions, oriented strictly toward a single end: success in populations’ survival and reproduction.
  3. Natural selection’s capabilities extend only to the point of supporting survival and reproduction. Its capacities do not include the ability to make survival and reproduction either right or wrong, good or bad. Therefore natural selection is not the sufficient cause, required per A.5.
  4. With respect to biological and behavioral features and functions, causation is closed on random variation and natural selection (with negligible contributions logically possible by sheer chance).
  5. Therefore there is no sufficient cause capable of causing real rightness or wrongness to begin to exist. (See comment 1 for more.)
  6. If real rightness or wrongness is not eternally existent (A.3.) and has not begun to exist (C.5.), then it does not exist now. Moral realism is not real.

D. Labeling Behaviors

  1. Evolution has, however, produced behaviors in humans whereby we label acts, intentions, and outcomes as good, bad, right, wrong, etc.
  2. These behaviors must have sufficient reasons explaining their existing in humans.
  3. With causation being closed as stated above, those sufficient reasons must be located in the realm of natural selection.
  4. Natural selection has only one capability, however: Supporting success in survival and reproduction.
  5. Therefore humans’ labeling behaviors must be an outcome of natural selection’s support for survival and reproduction.
  6. With no other cause on hand to produce other purpose or value attached to these labeling behaviors, these behaviors could not possibly have any other purpose or value.
  7. Therefore “good,” “bad,” “right,” and “wrong” are strictly and entirely labeling behaviors whose only purpose is to support human populations’ survival and reproduction.
  8. And since that is all that these behaviors are, given their genesis via naturalistic evolution, they could not possibly have any reference to real right or real wrong.

And that would seem to entail that there is no real right or real wrong, given naturalistic evolution.

But I’m open to your comments. Thank you.

Update: I’ve just discovered this site is having trouble accepting comments. Please comment on Facebook in the meantime instead. Fixed. Needed a database table repaired.

Image Credit(s): Steinar Engeland/Unsplash.

5 Responses

  1. Tom Gilson says:

    A.4 and C.5. may need some explanation as to what it means for moral realism to be, or for it to begin to be. I would say moral realism exists if and only if there is some condition X such that it is true that X is morally right or X is morally wrong, independent of human judgment.

    So for moral realism to begin to be, some condition must begin to be such that it is true that some X is morally right or morally wrong, where previously no such condition existed.

  2. I think the atheists would say that life is good. Life is what defines the good. So the good arose with the origin of life. This relates in particular to your point C.3.

  3. Steve Kwiatkowski says:

    Great post, Tom! I’d like to add, it seems that labeling certain behaviors “right” and “wrong” as they are now is just one option available to materialists to support human populations’ survival and reproduction . Wouldn’t another option be to label the killing of the sick and the weak as “right”? If the materialism is true, then why not? Culling the less fit is how every species supposedly arrived at where they are today. Why are humans now the only exception to this?

  4. “I would say moral realism exists if and only if there is some condition X such that it is true that X is morally right or X is morally wrong, independent of human judgment.”

    Do you mean “independent of sentient being judgement”? Because in that case I would agree with you. I don’t think objective absolute morality can exist on naturalism. But I don’t see how it can exist on any version of Theism either. Open to comments on how that could be.

    But to examine your points …

    A3 refers to “Moral Evaluations”. A4 refers to “real right and wrong”. You are talking about two different things there, as moral evaluations can begin to exist during the course of evolution, and I’m not sure how you can eliminate that real right and wrong did not exist into the past. Similar to how we can mathematically evaluate things now, but we think the math has been eternal. The sentient beings have just put language to what we observe. My point is, A4 does not follow from A3, and therefore neither does A5.

    B3 & B4, also contains a lot of B2. Evolution might be responsible for my particular DNA, but after I was born the material workings of the Universe are responsible for a lot of my behaviour. Nature and Nurture, if you will.

    C2. Natural Selection selects for an individual to survive and reproduce, not a population. The effect on the population is a by product of the change in an individual.

    C3. Your first sentence is incorrect. There are all sorts of secondary effects to the selection process of breeding and survival. The Russian experiment regarding the domestication of foxes showed many other changes, whilst they were breeding for only 1 criteria.

    D4 is incorrect because C3 is incorrect. Therefore D6 & D7 do not follow.

    And therefore D8 doesn’t follow. As above, we evolved to know math, which we think is correct despite our judgment. Therefore we could have evolved to know objective morality if it existed before us.

    Good to be talking to you again, Tom.

  5. BillT says:

    I don’t think objective absolute morality can exist on naturalism. But I don’t see how it can exist on any version of Theism either. Open to comments on how that could be.

    The classic explanation (if I can express it correctly) is that God is the summum bonum the “highest good.” This highest good is not something he decides but something he embodies. As we are all part of his creation we are subject to and and part of a world where his good is our good as well. It is part of the fabric of our existence. It creates a moral agency that results in a responsibility to others and makes a person accountable for their actions. It seems the only possible way an objective absolute morality could exist.

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