The principle of a contradiction demands that the thinking was consecutive. He demands that, approving something about something, we did not deny the same about the same in the same sense at the same time, i.e. forbids to accept at the same time some statement and its denial.
In logic operation of denial of judgment – transformation is more clear. It represents the action connected with change of quality of initial judgment – a sheaf. Thus the predicate of the received judgment has to contradict the initial. Thus the affirmative judgment turns in negative and vice versa. In the form of formulas it looks so:
The logic takes a special place in system of sciences. Feature of its situation is defined by that it carries out in relation to other sciences a methodological role the doctrine about general scientific forms and methods of thinking. The subject of logic is quite specific, are forms of thought. Therefore at an initial stage it is necessary to define that such thought, a thought form, thinking. Having addressed to philosophy as to science to related logic, it is possible to imagine thinking as a way of reflection of reality. There are some forms of reflection of reality which consecutive consideration leads to understanding of a subject of logic.
Due to change of one of elements of structure of concept are subdivided into types. On a quantitative sign – on single, the general and empty, and also on registering and not registering, collective and dividing. On a quality indicator – on affirmative and negative, concrete and abstract, relative and irrespective.
At denial of any judgment it is necessary to remember the principles of logic also. Four main are usually formulated: principle of identity, contradiction and sufficiency. Without going into details, it is possible to stop not the most essential to operation of denial of judgments.
Secondly, classification of concepts and judgments is carried out, proceeding from the general principles. Namely concepts and judgments are subdivided into types on quantitative and quality indicators. For example, concepts on a quantitative sign are subdivided into the general, single, zero, and simple categorical judgments the general, single, private.
Judgments of reality, need and opportunity are distinguished to the characteristic of a sheaf from simple judgments on qualitative. In general this group of judgments is considered as judgments of a modality which represents degree of reliability of this or that simple judgment.
Sign will be any property of a subject external or internally, obvious or directly not observable, the general or distinctive. The concept can reflect the phenomenon, process, a subject (material or imagined). The main thing for this form of thought – to reflect the general and in too time essential, distinctive in a subject. As the general signs what are inherent in several subjects, the phenomena, processes act. The sign which reflects internal, radical property of a subject is essential. Destruction or change of this sign involves high-quality change of the subject, so and its destruction. But it must be kept in mind that importance of this or that sign is defined by interests of the person, current situation. Two various properties will be an essential sign of water for the eager person and for the chemist. For the first – ability to satisfy thirst, for the second – structure of molecules of water.
If to unite a quality and quantitative index, all simple categorical judgments can be shared into six types: all-affirmative, all-negative, chastnoutverditelny, chastnootritsatelny, edinichnoutverditelny, edinichnooritsatelny.