There are many types of logical fallacies.

Logical fallacy refers to an argument that is not based on logic, especially an illogical inference in an argument. Logical fallacies are divided into formal logical fallacies and informal logical fallacies. Informal logical fallacies are essentially false premise fallacies.

Formal logical fallacies:

Formal logical fallacies refer to logical fallacies caused by reasoning, deduction, and argumentation that do not follow formal logical reasoning rules:

1. Fallacy of negating the antecedent

Typical form: "If A, then B; not A; therefore not B."

Example: "If it is a bird, it will die; a human is not Birds; old friends do not die." This is a misuse of the categorical syllogism. The correct form of a categorical syllogism should be: "If A then B; A; therefore B."

2. Affirmative consequential fallacy

Typical form: "If A then B; C is B; therefore C is A;”

Example: “If it is fried dough sticks, then it is delicious; the bread is delicious; therefore the bread is fried dough sticks.” This is also a misuse of categorical syllogism. .

3. False dilemma reasoning

Typical form: "A or B or C; not A; therefore B."

This is a disjunctive syllogism misuse. The form of a disjunctive syllogism: "A or B; not A; therefore B.", cascaded into this form: "P1 or P2 or P3...or Pn; not P2 and not P3...and not Pn; Therefore P1. "In the words of Holmes: "When all other possibilities are eliminated, it is the truth, no matter how impossible it seems."

The reason why. This fallacy is called a false dilemma, because sophists often express it in this form: "For sweet food or for salty food; you are not for sweet food, so you are for salty food." Sophists deliberately use "neutral" in their statements. This option is hidden, creating the illusion of a disjunctive syllogism. It is worth noting that some people tend to classify false dilemmas as informal logical fallacies.