The term fallacy is used to indicate that an argument is apparently valid. Fallacy is equivalent to sophism and etymologically comes from the Latin fallacia and this from the verb fallere, which means to deceive. On the other hand, in the proper terminology of logic it is called fallacy and reasoning errors . Naturalistic Fallacy
The naturalistic fallacy is a very common type of error in ethical arguments.
When homosexuality is said to be unnatural and because of that immoral, a false argument is used. When it is said that something is morally good because it is natural, it also makes a misleading argument. In a nutshell, the falsehood component consists of starting from a concrete and objective reality to a moral criterion that should be correct.
In philosophical terms, the logical inconsistency of this fallacy is based on the fact that it is impossible to deduce the duty of being something from its being. Philosophers such as David Hume and Richard Pierce argue that the ethical doctrines that goodness is reducible to a natural property fall into the naturalistic fallacy. In short, claiming that the natural equals what is good is an unfounded ethical assessment.
In addition to the strictly philosophical question, it must be taken into account that this inconsistent and misleading reasoning can be used for two distinct reasons. On the one hand, intending to deceive or manipulate someone or, conversely, because its false dimension is unknown is considered a valid form of argument.
The justification of slavery is a classic example of the naturalistic fallacy.
For centuries slavery was considered a normal and morally accepted practice. Thus, there were powerful men of a supposedly superior race who subjugated others of a race valued as inferior.
The phenomenon of slavery was socially accepted for several reasons: it was a tradition based on the “superiority” of some individuals over others, it was understood that the right to property should prevail over other individual rights and, finally, it was believed that the master acted correctly to be responsible for an inferior being.
The submission of some people was socially normalized and therefore seemed natural. Consequently, the fact of being against slavery had an unnatural dimension and, in parallel, those who went against the “natural” were considered incorrect from a moral point of view.