Naturalistic Fallacy and Bias (Definition + Examples)

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Fallacies in their various forms play an important role in the way we think and communicate with others. A fallacy is any reasoning that contains flaws which make an argument invalid. Formal fallacies occur due to a fault in the argument’s logical structure, whereas informal fallacies are a result of reasoning errors. One of the common informal fallacies is the naturalistic fallacy. 

What Is Naturalistic Fallacy? 

The naturalistic fallacy is the faulty assumption that everything in nature is moral by default. According to this reasoning, if something is considered being natural, it is automatically valid and justified. In the same way, any unnatural behavior is morally unacceptable.

Examples of Naturalistic Fallacy 

Opponents of genetic modification and cloning, for example, claim that since these processes are unnatural, they are by definition undefendable and unethical. Or, some may argue that the fact that marijuana is a plant that grows naturally makes its legalization perfectly justifiable. 

A user in the DebateaCatholic subreddit brought up the naturalistic fallacy when discussing some of the stances that the Catholic church made on abortion, contraception, etc.: 

"I have noticed basically everything Catholics say on this suffers from the naturalistic fallacy: basically, something is good because it is natural.

In this case: babies from sex = natural, therefore don't try to stop it...

The same reasoning could be used to abstain from any kind of medical treatment, though: during pregnancy, birth, etc. I think I have an argument here for mothers to abstain from any form of painkillers during birth: John 16:21Genesis 3:16Genesis 1:28 could be used to argue for reproduction, but not directly against birth control; one could choose to have more children in the future."

Basing religious doctrine on thinking influenced by the naturalistic fallacy show why it's so important to be aware of this concept.

Why Is This Train of Thought a "Fallacy?"

It is clear that regarding all natural occurrences as moral can bias our thinking. In fact, in many instances, naturalness does not in itself make an action good or bad. Consider the following statement. Animals naturally fight in the wild, as a consequence, it is morally acceptable for humans to fight. This is a naturalistic fallacy—even though this behavior comes naturally to animals, violence among humans is generally seen as morally wrong.

Who Introduced the Naturalistic Fallacy?

The idea of naturalistic fallacy was first discussed by Scottish philosopher and historian David Hume in the 18th century. The term was coined by British philosopher George Moore in his book Principia Ethica in 1903. Moore argued that whenever philosophers try to make ethical claims using terms for natural properties like “pleasant”, “satisfying”, or “desirable”, they are committing the naturalistic fallacy.

Moore believed that it is impossible to define morality in terms of any natural properties or concepts except for itself. An attempt to do so would be fallacious. Because morality cannot be explained, it needs to be understood intuitively and on its own terms. According to Moore, therefore, all ethical questions are simply open-ended and unanswerable. 

The naturalistic fallacy is closely related to the is-ought fallacy, described in Hume's book A Treatise of Human Nature in 1740. 

Is-Ought Fallacy

The is-ought fallacy refers to the arguments that move from facts (what is) to value judgments (what ought to be). This type of fallacy has two logical forms: 

“X is, therefore, X ought to be” and 

“X is not, therefore, X ought not to be”.

The is-ought fallacy occurs when the assumption is made that because things are a certain way, that is how they should remain. Given that women have traditionally cared for children, for example, their role in today’s society should be to look after the family. In other words, the status quo should be maintained for its own sake.

The is-ought fallacy can also consist of the assumption that because something is not occurring right now, it should not occur at all. For instance, the amount of nicotine in individual cigarettes is currently not regulated, thus, it should not be regulated. Once again, a moral imperative is derived from the description of a state of affairs. 

Reverse Naturalistic Fallacy 

While is-ought fallacy seeks to make a value of a fact, the reverse naturalistic fallacy or moralistic fallacy does the exact opposite. It justifies what “is” based on what one believes “ought” to be. A moralistic fallacy is any belief that the world is, from the moral point of view, just as it should be. 

To illustrate, if prisons are full of people who committed crimes, then we cannot claim that mankind is inherently good. Or, men and women ought to be equal, thus we can agree that women are just as strong as men, and men are just as empathetic as women.

Another example of a moralistic fallacy is reasoning that since war is morally wrong, humans do not have any predispositions toward engaging in war. Yet we know that humans have been fighting wars for thousands of years. Just because violence is commonly considered as morally wrong, does not mean that humans have no tendency to fight.  

Appeal to Nature Fallacy

The naturalistic and the moralistic fallacies are often confused with what is known as the appeal to nature. 

When it comes to the naturalistic and moralistic fallacies, the conclusion of an argument is not necessarily based on what is natural but simply on what “is”. The central aspect of the naturalistic fallacy is the idea that what is natural can’t be wrong. If something is true according to nature, then it is morally right. 

The naturalistic fallacy can be seen as a subset of the appeal to nature that focuses on a moralistic value rather than the more general idea of goodness.

In an appeal to nature, something is considered as good owing to the fact that it is natural. Likewise, it is bad if it is unnatural. Following this reasoning, one can argue that everything that is natural can be safely ingested by human beings. This may, for example, include nicotine in spite of the fact that we are aware of its harmful effects.

The appeal to nature is further based on the idea that what is natural is always better than artificial. If we are able to find an instance of certain practice in nature, that same behavior should be acceptable to human beings. 

Examples of Appeal to Nature Fallacy 

One of the most common occurrences of appeal to nature is defending meat eating. Some maintain that if animals eat meat, then consuming meat is natural and as such justifiable for human beings as well. Unlike the naturalistic fallacy, the appeal to nature does not take morality into consideration. 

By the same token, alternative health advocates believe that herbal remedies should be used for treating various medical conditions because they are more natural than modern treatments. The fallacy clearly contradicts the scientific fact that some natural remedies are neither safe nor effective. What matters the most in this type of fallacious argumentation is the naturalness of the process.

Reference this article:

Practical Psychology. (2020, May). Naturalistic Fallacy and Bias (Definition + Examples). Retrieved from

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