Overview: The appeal to nature occurs when someone argues that something is good or healthful simply because it is natural. The appeal to nature can often be implied whenever someone argues that something is bad or unhealthful simply because it is unnatural. Because the latter version comes up so often in anti-science propaganda, I’ve started calling it the appeal to chemicals.
Details: The appeal to nature is classified as an informal fallacy subset: failure of relevance. The appeal to nature assumes that if something is natural then it’s good, harmless, or healthful. It doesn’t take much to come up with counter-examples. Lots of mushrooms are natural but no one would recommend eating every kind of them. Or as I like to say, “dirts natural, why don’t you eat that?”
Logical Analysis: Identifying counter-examples is one way to show that an argument form fails but it doesn’t tell us why it’s a poor argument. To understand why the appeal to nature is always a poor argument (even when it yields a true conclusion sometimes) we need to dive into a little argument analysis.
First, we need to put the argument into standard form. We start like this:
- [X] is natural.
- Therefore, [X] is good.
The argument as stated is missing a premise. We need a premise that logically connects the idea that something is natural to the idea that it is good. Almost all arguments presented in the wild have these missing premises called enthymemes. However, to properly evaluate an argument we must include the enthymeme [click the link to go to my lesson on identifying enthymemes]. So, the complete argument looks like this:
- [X] is natural.
- If something is natural then it is good/healthful/safe, etc…
- Therefore, [X] is good/healthful/safe, etc…
Now it’s pretty easy to see why any argument that takes this form fails. The second premise is false. So, no matter you insert for [X] the argument will be invalid since arriving at the conclusion will always depend on a false premise.
Concluding Thoughts: The Appeal to Nature fools most people because I think most people equate what is familiar with what is natural. If something is familiar there is actually a reasonable presumption that it is safe or healthful. However, (a) this is only a presumption and (b) it tells us nothing about its relative health/safety merits compared to a designed product. Similarly, the fact that something isn’t “natural” (or familiar) doesn’t tell us automatically that it’s bad. It’s reasonable to suggest that new products bear the burden of proof but often anti-science propaganda (a) offers no suggestion for what would be required to meet that burden of proof or (b) moves the goal posts with respect to the burden of proof (c) demands an impossible burden of proof (d) fails to consider the costs of not adopting a new technology.
Whether something is natural or synthetic or processed tells us little about its safety, healthfulness, or general goodness. It only tells us about is origins or the process by which it was produced. If we want to know whether something is safe, healthful, etc… then we need to conduct/find studies evaluating those properties that we’re interested in and we need to (before hand) agree on realistic standards of evidence.
Nerd Stuff: Appeal to Nature vs Naturalistic Fallacy. The appeal to nature is used to argue that something is good/healthful/safe, etc…because it’s natural. The naturalistic fallacy is a bit more complicated although in everyday speech it’s perfectly fine to use the two interchangeably. Very broadly, the naturalistic fallacy is committed when someone argues that a behavior or social convention is morally good because it’s natural. For example, someone might say it’s natural for women to be in charge of childcare therefore they should do it (i.e., it’s morally good that women not men be in charge of it). There are entire books written on the various interpretations of the naturalistic fallacy in moral philosophy. If you’d like to know more than you would probably even need to know about it click the link to my blog post explaining the various interpretations. You can also read about it in the first part of this SEP article.