As a difficult point in the logical judgment of the test, the hypothetical proposition has always brought a lot of "torture" to the majority of candidates, and the reasoning rules of the hypothetical proposition are precisely a knowledge point of the common test of hypothetical propositions. Today, we have brought you a combing of the relevant knowledge points of the reasoning rules of hypothetical propositions and some classic example questions, hoping to help the majority of candidates.
Knowledge point combing].
One. Definition: Hypothetical propositional reasoning rules: p q non q non p (also known as the inverse negative proposition of hypothetical proposition).
Chinese summary: Ken before must be willing to be equivalent to no after must be before no.
Two. Details: 1) p q (before and after):
In hypothetical propositions, when the antecedent of the hypothetical proposition is affirmed, the posterior of the affirmative hypothetical proposition must be introduced.
Example: If the weather is fine tomorrow, I'll go fishing with you. Tomorrow the weather is really clear, what conclusions can be made?
Correct answer: I'll go fishing with you.
Analysis: The question stem is a hypothetical proposition that is pushed forward and backward, and the launch relationship is: tomorrow the weather will be sunny I will go fishing with you, and tomorrow's weather will be really sunny is the precursor of affirming the hypothetical proposition, according to the principle of p q (willing before and after willing), affirming the antecedent of the hypothetical proposition, we must launch the affirmative hypothetical proposition, and thus get the conclusion: I will go fishing with you.
2) Non-Q Non-P (No after must be no before):
In hypothetical propositions, when the posterior of the hypothetical proposition is denied, the antecedent of the hypothetical proposition must be introduced.
Example: If the weather is fine tomorrow, I'll go fishing with you. I didn't go fishing with you tomorrow, what conclusions can I get?
Correct answer: The weather will not be sunny tomorrow.
Analysis: The question stem is a hypothetical proposition that is pushed forward and backward, and the launch relationship is: tomorrow the weather will be sunny I will go fishing with you, and tomorrow I will not go fishing with you is the posterior of the hypothetical proposition, according to the principle of non-q and non-p (no must be no before), the posterior of the hypothetical proposition must be launched, and the conclusion must be made: the weather will not be sunny tomorrow.
From the above knowledge points, we know that the reasoning rule of hypothetical propositions is that the precedent must be agreed to be the equivalent of the negative and the necessitated before, otherwise it is invalid reasoning, such as the affirmation and the no, it is impossible to deduce the inevitable conclusion. So how does Ying apply these rules of reasoning in the exam?Take a look at the following examples:
Classic examples] examples. All living organisms need metabolism, otherwise life will stop. The same is true of civilization, if it closes itself off for a long time, it will inevitably decline. Exchange and mutual learning are the essential requirements for the development of civilization. Only by exchanging and learning from other civilizations and learning from each other's strong points can we maintain our vigorous vitality.
From this it can be deduced:
a.A civilization will not go into decline if it does not close itself off for a long time.
b.A civilization cannot maintain its vigor and vitality if it does not have exchanges and mutual learning with other civilizations.
c.If a civilization exchanges and learns from other civilizations and learns from each other's strong points, it will be able to maintain its vigorous vitality.
d.If a civilization does not maintain its vigorous vitality, it does not learn from the strengths and weaknesses of other civilizations.
Analysis] The answer is b. The stem conditions can be transformed into: civilization has been self-enclosed for a long time and is declining; Civilization maintains its vigor and vitality, and exchanges and mutual learning with other civilizations.
Item A can be transformed into the following: Civilization does not enclose itself for a long time and will not go into decline, and the negated antecedent cannot lead to the negation of the posterior, wrong.
Item B can be transformed into the following: Civilization cannot maintain its vigorous vitality without exchanges and mutual learning with other civilizations, and the negative posterior can be used to introduce the negative antecedent, which is correct.
Item c can be transformed into: Civilizations exchange and learn from other civilizations, learn from each other's strong points, maintain vigorous vitality, and affirm the latter cannot lead to the affirmative antecedent, and make mistakes.
Item d can be transformed into the following: Civilization has not maintained its vigorous vitality, has not learned from other civilizations, and the negation of the former cannot lead to the negation of the latter, and the error.
Therefore, B is selected for this question.