logic, as you know, is made up of been approved, and conclusions.One of its basic building blocks - a categorical syllogism - this conclusion, ranked deductively, that is, the conclusion of special positions of some general.It derives from two main arguments, or parcels, linked by a common term.Because such arguments only two, called a simple syllogism, and due to the fact that the parcels are approved (or denied) quite categorically, such a simple statement called categorical.Here is the simplest example of such reasoning.The first argument: "All men are mortal."The second argument: "Ivan - man."The conclusion he's judgment, therefore, is: "Ivan - mortal" As we have seen, rightly or wrongly all parcels is not considered here.We take for granted the fact that human life is ever completed, and Ivan belong to the human race.

For example, this unpretentious conclusions, we can see that the simple categorical syllogism has its own structure.In any logical inference predicate (the word with a certain undefined value, in our case - mortal beings) is always wider than the subject (Ivan).Therefore parcel containing a predicate, it called a large, but one that includes the subject - small.Binds these arguments term intermediary M (medium) - in this case, people, man.Therefore, in the jurisprudence of the logical inference analysis must begin with finding a place in it and the predicate of the subject, as well as the presence of a mediator between them.

In this analysis, it should be noted that a simple categorical syllogism should contain an axiom that is not expressed, but it is: everything that is approved or denied of all kind of items apply to each item of this type.Therefore, such a proposal would be erroneous: 1. The men become fathers.2. Peter - man.3. Peter - his father.In this example is not followed the axiom of the syllogism, as fatherhood does not apply to all men.Therefore, the construction of reasoning necessary to strictly adhere to the rules.There are only seven: three of them relate to the terms and four - parcels.

Rule one: simple categorical syllogism contains only three terms.Every fourth term - once.The identification of the different concepts implies error.For example: 1.Sidorov committed theft.2. Sidorov - noun.3. The noun has committed a theft.There Sidorov and noun have different meanings.Rule two: The term proxy must be present in the premises.If the connection between the subject and the predicate can not be set or she remains unproven, it remains fragile and the syllogism: 1. Some people - murderers.2. Ivan can be called to some man.3. Ivan - killer.And finally, the third rule.If the argument of the predicate without using the term, but it is present in the conclusion, it will be invalid syllogism.Examples of such errors can be expressed as follows: 1. In the Moscow region the case of murder.2. St. Petersburg is located in the Moscow region.3. In St. Petersburg, not a murder case.

except the right terms should comply with the rules of parcels.At least one of them must carry a statement, because to approve anything, we have to up something repelled.If one of the arguments put forward - denial, then the conclusion must be negative.Also, in order to just get the right categorical syllogism, at least one of the arguments put forward have to be of a general nature of categorical judgments.And the last rule parcels: if at least one of them - a private, then the conclusion must be private.For example: 1. The offense must be punished (summary judgment).2. Ivanov has committed a crime (a particular case).3. Ivanov should be punished.