Naturalistic Fallacy

The Naturalistic Fallacy occurs when evaluative conclusions are drawn from purely factual premises. This is related to the is-ought fallacy. 

Some say that the naturalistic fallacy consists of defining a non-natural property like "goodness" or "happiness" in terms of natural (as opposed to spiritual) properties. Others say that the naturalistic fallacy consists of defining one property, such as "goodness" or "happiness" in terms of other properties. Others say that the naturalistic fallacy consists of defining an undefinable property.

To rationally use the term, "undefinable property" will require that we know what is undefinable. If one were to say that no one could define a certain property, say, "goodness," that person would be committing the logical fallacy of declaring a universal negative. That person would be claiming to know that no one, not even God, could define it. That person would be claiming that God could not reveal the definition to anyone. Such a claim would be irrational. Alternately, a claim is sometimes made like this: "That doesn't make any sense." As a syllogism, this would be, "Things that I personally don't understand are not part of reality. I don't understand the concept you are talking about. Therefore, it is not part of reality." This point out the fallacy of this claim. The "undefinable property" may be cited and a reference in a text book given to "prove" that this is a "real fallacy." This is a definist fallacy in which "undefinable property" as "anything that I don't personally understand." An undefinable property cannot be a situation in which the person who is defining a property cannot define the property. That definition is self-refuting. As of this writing, there is no way to make the "undefinable property" a rational part of the naturalistic fallacy.

G. E. Moore claimed, in the book, Principia Ethica (1903) that a naturalistic fallacy is committed whenever an appeal is made using the word, "good" in terms of one or more properties such as "pleasant," "more evolved," or "desired." Moore termed this as "natural" properties. Is Moore right that this would be a fallacy? On what basis? Can you define that without making any hidden assumptions, without any circular reasoning, and without infinite regression? The Atheistic paradigm cannot comment on "goodness" rationally. The definition of "goodness" or "happiness" from an materialistic paradigm is that there is nothing beyond the natural. Natural is defined as material; just energy and matter.

Another definition of the naturalistic fallacy defines it as occurring when two words are thought to be synonyms simply because they are used to define the same object. There is a tendency to focus on "good" as one of the words that is used to define said object. There is a relationship between the naturalistic fallacy and the is-ought problem. Sometimes, it is thought that they are one and the same. In reality, there is none good but God, which makes this a terrible problem for Atheists to make any rational statement regarding good or evil.

Sometimes, the naturalistic fallacy is defined as trying to draw ethical conclusions from observations in the material realm. Sometimes, the naturalistic fallacy is defined as a claim that what is good or right is natural or inherent. Without Divine revelation, it is truly a fallacy to make any statement in regard to truth, morality, ethics, theology, Biblical study, or anything of this sort. It is impossible to know anything about ethics or morality except by Divine revelation. In fact, Agrippa's Trilemma makes all knowledge outside of Divine revelation impossible. This is because a chain of thought is as strong as its weakest link. This chain must begin with something that is absolute, but all that is available is infinite regress, circular reasoning, or axiomatic thinking. These three have exactly zero truth value.

Fallacies that Sound Similar

There is the unnatural fallacy, the naturalistic fallacy, the proof by appeal to Naturalism, the fallacy of Naturalism, and the appeal to nature. You will find these fallacies all confused together in various sources. There seems to be no agreement. In addition, there are many definitions of the word, "natural." Although, it doesn't pay to get dogmatic about a certain definition, it would be nice to know what various authors are trying to say. Remember that the goal is to be able to tell truth from fiction.