Deductive essay is an elimination of the justification of the other previously adopted regulations. If the extended position can be deduced from the already established regulations, then it is acceptable to the same extent that these provisions. The rationale of some statements by reference to the truth or acceptability of other claims is not the only function performed by the deduction in the process of reasoning. Deductive reasoning is also used to verify the assertions of verifiable provisions deductively derived its empirical investigation, confirmation of these effects is estimated as an inductive argument for the starting position. Deductive reasoning is also used to falsify claims by showing that their consequences are false.

Deductive reasoning is universal, applicable to all areas of knowledge and in every audience. “If happiness is nothing else than the eternal life”, writes the medieval philosopher I.S.Eriugena, “And eternal life is the knowledge of truth, happiness – is nothing but a knowledge of the truth”. This is a theological argument in a deductive inference, namely, the syllogism.

Knowledge of human origin are divided into immediate, gleaned from experience, and indirect, lead. A decisive role is played by the inferential knowledge, in which most clearly opens up the activity distribution of the human mind. The basic logical thinking is a form of indirect inference.

Inference is regarded as a form of thinking through which of the single or more judgments derived from the necessity of new knowledge about the objects of the real world.

The distinctive feature of the reasoning consists in the movement of thought from some judgments and concepts to others, one of the content of knowledge derived new knowledge. The logical inference from the act is not only in the analysis of the already known knowledge, but also in the synthesis but-wave data obtained from the experience in moving from known to unknown.

In any inferences are three main points:

1. Initial knowledge (parcels);

2. Justifying knowledge (logical ground output);

2. Inferential knowledge (conclusion).

The truth of the outflow of knowledge depends on the validity of assumptions and logical correctness of their relationship. According to the degree of community, premises and conclusion inferences can be divided into three groups:

1. Deductive, when a thought comes to people’s knowledge;

2. Inductive, when the idea developed from the knowledge of one of degree of generality to new knowledge greater degree of generality;

3. By analogy, when the parcel and express a conclusion cheap-sound knowledge of the degree of generality.