From Latin fault, a fallacy is a lie or scam with which it is intended to harm a person without her noticing. A person who discovers that he has been a victim of a fallacy can express, for example: “The fallacy of their employment made me live deceived for many years”, "Pablo is always with his fallacies, trying to scam people". A person uses a fallacy to get something he knows could not get otherwise than through the appeal to the falsehood Generally, your intention is not precisely to harm, but to make a profit, but you are not worried about hurting others to get what you want.

In the logic The concept is also used to refer to an argument that attempts to defend something that is false. We will explain it better below.

According to the dictionary definition, the logic is the thought science, which allows to analyze a reasoning and determine whether or not it is correct. Anyway, within this science there are several branches: diffuse and constructive logic and within each one different currents.

The Boolean logic It is the best known and seems to be the only one considered by the common people, although it is important to keep in mind that it is not the only one. Within this it is defined as a proposition those statements that may have true or false character; it is the essence of a reasoning. It is important to note that the proposition does not refer to the way in which the sentence is conjugated but to its meaning, which does not vary even if the preposition is reformulated.

For example:
"There is an even prime number greater than two" is the same preposition as "An even and prime number that is greater than two exists", even if the words are arranged differently. In any case, it is important that when rephrasing a proposition its meaning is not changed, that is why it is so important to make proper use of the language. For this reformulation the formal linguistics that allows analyze the sentences and rewrite them without changing their essential meaning.

Regarding the fallacies, although it may seem a simple task to construct a deductive reasoning, however many times we find very common mistakes, which lead us to conclude that a reasoning is not at all precise. East technical defect in the way of posing a reasoning is known as fallacy.

Those arguments that contain fallacies are known as fallacious and have the peculiarity that they generally seem valid and even convincing at first glance and only through an exhaustive analysis can we become aware of their "deception."

In short, a fallacy is a sophism , an apparent refutation that is used to defend something false, exposing false premises as true. It is a reasoning that appears to be logical, but whose result is independent of the veracity of the premises.

The logical fallacy therefore, it implies an incorrect application of a valid logical principle. It can also be formed by the application of a non-existent principle.

An example of fallacy is as follows:

1. Emeralds are green
2. This ring is green.
3. Therefore, the ring is emerald.

The two premises mentioned may be true, however, the conclusion is not necessarily true. The ring can be made of emeralds or other green material. In the first case, the conclusion would be true, but, in the second, we would face a false conclusion.

Another example of fallacy, known as ad hominem , it happens when the person who makes a statement is disqualified to, in this way, also disqualify their sayings:

1. Martin says he saw how Pedro stole money.
2. Martin usually lies.
3. Therefore, Peter did not steal the money.

In these cases, the fallacy does not address the validity of the statement, but refutes the person making the claim.