Improper Use of Hume’s Is-Ought Problem and the Naturalistic Fallacy in Evolutionary Arguments




It should be no secret that I’m no fan of regurgitated arguments. If you’re going to recite a standardized argument as your own, you should first understand the argument. Evolution deniers spout off lies about “missing links” and “no facts to support” and “it’s just a theory” to perpetuate their vapid argumentum ad ignorantiam and arguments from incredulity. Partisan supporters of supply-side economics rattle off rhetoric about lower taxes increasing investment spending without any idea what the Laffer curve is – let alone the understanding required to argue that tax rate X is at or beyond its peak, or that its peak is the same for any individual Y or population Z.

Henceforth, I trust I shall hear nary a word of such contrivances of abominable nonsense. No dear sirs and madams, not so much as a peep.

This article isn’t about a full analysis of the philosophy of the naturalistic fallacy, the nuances that distinguish it from Hume’s “is-ought” problem, or Hume’s extensive, reasoned, and persuasive arguments on the topic. This is a precursor for my upcoming writings that will leave naive regurgitators of Hume behind. I’m not going to [intentionally] violate Hume’s arguments, but people who invoke the is-ought problem too often don’t understand him. This article, and its references, are where I will direct the unsophisticated who attempt to speak Hume’s name in vain in attempts to dismiss my endeavor out of hand by rhetorical slight of hand.

And no, the irony of quoting others arguments to make my argument in light of the first paragraph is not lost on me. However, be advised that I have read these papers and generally understand the arguments within.

The Naturalistic Fallacy

In a nutshell, the fallacy is typically reduced to “ought cannot be derived from is”. Things that evolved through Darwinian selection are natural, or what “is”, but that doesn’t mean we can justify them by then saying that they “ought” to be simply because they’re evolved characteristics.

Fourth Commandment: Thou shalt not take the name of the Scottish philosophers in vain: for the Scottish philosophers will not hold him guiltless that taketh their names in vain.

*King James, a Scotsman, really should have gotten this right the first time.

To take one of the most emotionally charged examples to illustrate the legitimate concerns… Some have argued for rape as an evolved strategy for increasing reproductive success in humans and other animals. The emotional nature of that question tends to preclude rational discussion, but it hasn’t been definitively answered one way or another. However, it becomes a political discussion when some assume that an ought can be derived from an is. The scenario as it stands would be invalid even if factually true (a premise that’s factuality is debatable).

Invalid structure:

Sexual rape of another person to increase reproductive success is an evolved behavior (factual premise).
Sexual rape of another person is right (ethical conclusion).

Hume would regard the following argument as deductively invalid:

Torturing people for fun causes great suffering (factual premise).
Torturing people for fun is wrong (ethical conclusion). (Wilson et al. 2003)

The problem is that Hume’s name and the naturalistic fallacy are often invoked any time something “is” or is natural is being discussed – as an implied refutation or an attempt to silence discussion. That’s not a problem in the two previous scenarios, but Hume explicitly outlined a path to making the connection. And… it’s not a complicated path so it’s easy to misapply the fallacy when its use is attempted without understanding it. Simply: one additional clause is required. Unfortunately, the argument is often dropped from the sky whenever an argument begins with a natural “is” and ends with an “ought” without respect to one, two, or a zillion additional clauses between them. This is a fundamental flaw in argumentation that can be (and regularly is) exploited for emotional and political purposes, then spread through the minds of those naive to what Hume actually said.

Various arguments obscured by the term “naturalistic fallacy”

*Section quoted from (Curry & Oliver 2006) but arranged in normal style for formatting and readability

“The first thing that anyone wishing to investigate the naturalistic fallacy discovers is that there is not one but many arguments that go by this name. A survey of the literature reveals not one but (at least) eight alleged mistakes that carry the label “the naturalistic fallacy”:

  1. Moving from is to ought (Hume’s fallacy).
  2. Moving from facts to values.
  3. Identifying good with its object (Moore’s fallacy).
  4. Claiming that good is a natural property.
  5. Going ‘in the direction of evolution’.
  6. Assuming that what is natural is good.
  7. Assuming that what currently exists ought to exist. 8. Substituting explanation for justification.
  8. Substituting explanation for justification.
This article has discussed eight different versions of the “naturalistic fallacy”, and shown that none of them constitute obstacles to Humean-Darwinian meta-ethics. Of course, there may be other versions of the naturalistic fallacy, or other arguments altogether, that succeed in establishing that moral values inhabit a realm distinct from the natural, rendering Humean- Darwinian and other naturalistic meta-ethics untenable.”

Hume already resolved the “problem”

As I said earlier, Hume’s only requirement to proceed from “is” to “ought” was than an additional clause must be added to the equation.

More generally, a factual statement must be combined with an ethical statement to derive an ethical conclusion . Hence, ought cannot be described exclusively from is. The word “exclusively” is a crucial part of the naturalistic fallacy. If we remove it, the statement “ought cannot be derived from is” implies that the facts of the world have no relevance to ethical conclusions. (Wilson et al. 2003) [emphasis mine]

To resolve the invalid inductive example a few paragraphs back:

if we supply an additional premise, the argument can be made deductively valid:

Torturing people for fun causes great suffering (factual premise).
It is wrong to cause great suffering (ethical premise).
Torturing people for fun is wrong (ethical conclusion).

The addition of the ethical premise takes this from fallacy to logically stable footing. It certainly leaves open challenges to the premises, but not in terms of Hume’s critique.

My use of “is-ought”

I’m going to outline the general structure of my premises and conclusions, but be aware that this structure is not in itself necessarily complete. It can’t always be used alone to derive an ought from an is. Further, it appears problematic in that the grammatical construction appears somewhat circular. However, Darwinian evolution is a feedback mechanism. Thus, the circularity is not without merit.

Human nature is shaped by evolution (factual premise).
Judgments of right and wrong are made based on evolved biases and influences (ethical premise).
Examining human nature can lead us to insight on right and wrong (ethical conclusion).

In other words, if we’re using brains that have evolved ethical cues, all ethical premises are influenced by evolution. Thus, knowing about our evolved biases can help us answer questions in this realm. Further, this can help to spot sociocultural mismatches and assist in reconciling them with human nature apart from power structures.

A less nebulous example:

People evolved psychologically under politically egalitarian hunter-gatherer arrangements (factual premise).
Authoritarian structures are wrong because they limit freedom (ethical premise).
Imposing authoritarian structures on people is wrong (ethical conclusion).

Plainly, my conclusion that authoritarian structures are ethically wrong is subject to the factual premise and the ethical premise. As such, my conclusion are open to falsifiability in the face of sufficient damage to the premises. However, dismissal by illusory chants of “naturalistic fallacy” and clinging to the scraps from Hume’s table are not enough to lodge a successful complaint. At least… not according to Hume. Perhaps your intellect surpasses his, but I’m happy to bet against that occurrence.

Looking at this example more deeply reveals that I am merely adding a factual premise to a commonly asserted ethical premise. Paradoxically, this both bolsters the ethical premise while opening the endeavor to scrutiny by misapplication of Hume’s observations. This trick opens the door to questioning the ethical conclusion by the mere addition of the “is” to the equation. Beware incantations along any of these critical lines; cries of naturalistic fallacy violation may the be simple cries of ignorance.

My goal in future work is to continue to add and refine factual premises to bolster other commonly held ethical premises. Some will take Hume’s name in vain, but do not be distracted by the decontextualization of the is-ought problem and Hume’s own resolution.


Yes, that heading is a bit dramatic. I just wanted to point out that the two references not specifically invoked above have specific bearing on the application of evolutionary psychology in the way I’m using it. There is no doubt that the nurture Nazis will complain that evolutionary psychology is a hoax bla bla bla. If that’s your position, you’re wrong (Teehan et al. 2004; Walter 2006). But more on that later.

Curry, Oliver. “Who’s Afraid of the Naturalistic Fallacy?” Evolutionary Psychology (2006): 234-247. [pdf]

Teehan, John, and Roosevelt Hall. “On the Naturalistic Fallacy : A Conceptual Basis for Evolutionary Ethics.” Evolutionary Psychology (2004): 32-46. [pdf]

Walter, Alex. “The Anti-naturalistic Fallacy : Evolutionary Moral Psychology and the Insistence of Brute Facts.” Evolutionary Psychology, no. 1999 (2006): 33-48. [pdf]

Wilson, D.S., Eric Dietrich, and A.B. Clark. “On the inappropriate use of the naturalistic fallacy in evolutionary psychology.” Biology and Philosophy 18, no. 5 (2003): 669–681. [pdf]