The speech – thinking tool therefore to each mindset there corresponds the language: the priest will not begin to preach a sermon on a criminal slang, and the young man in love – to say with the girl on a date as the diplomat at negotiations. The science has the "language" reflecting features of a scientific view on the world too. It is also the categorial device.
The categorial device is called the system of concepts used by any given science. These concepts generally reflect those properties and communications of objects and phenomena which this science investigates. For example, both for physiology, and for psychology the object of study is the person, but the psychology investigates reflection of reality in the course of higher nervous activity, and physiology – regularities of functioning of an organism in general, separate bodies and their systems. Therefore also categorial devices of these sciences differ. The basic concepts in psychology – consciousness, the personality, activity, and in physiology – an organism, fabric, body.
Scientific category
The concept of category is entered by Aristotle. In the literal translation from Greek this word means "charge" (the accusatory statement stated in court is meant). Aristotle treated it as "statement", "statement". In such sense he applied this term to the most general signs of things. Any scientific concept – result of generalization of a set of the concrete facts established during observations and experiments. Introduction of new category always marks certain "break", the beginning of a new stage in science. The categorial device is not just set of scientific concepts, namely the system of the interconnected categories. Change of semantic filling of one concept will inevitably cause change of other categories therefore the interpretation of scientific concepts changed from an era by an era together with a world picture. For example, understanding of matter in Levkipp and Democritus's philosophy differs from modern idea of it.
Definiteness of scientific categories
The paradoxicality of scientific concepts is that at all the generality they are extremely concrete. For this reason teachers demand from students of knowledge of definitions of scientific concepts, and scientists quite often argue on a formulation of definitions. Such attention to a limit specification of sense corresponds to a scientific view on the world which assumes establishment of the objective facts. Similar concreteness leads to the fact that the same word, being present at an arsenal of different sciences as scientific category, can make different sense. Especially, these values will differ from that sense which is given to this word in ordinary communication. For example, in psychology the word "activity" is understood as active interaction with the world around ("game activity", "educational activity"), and physiologists speak about "warm activity", "patrimonial activity". In daily occurrence of the word "feelings" and "emotions" are often used as synonyms, but in psychology they are meant as the different phenomena of the emotional sphere. Thus, the categorial device reflects both a scientific picture of the world in general, and that its part which is created by a certain science.