p We have noted earlier that most kinds of knowledge are, in one way or another, objectified and consolidated in a system of specific mediator objects—implements, instruments, symbols of oral and written language, scientific texts, schemes, diagrams, drawings, etc. There are also kinds of knowledge that exist in a subjective and not objectified form, such as perception. But, as we have tried to show, they are also genetically and functionally mediated by the man-made world of artificial objects embodying social-historical experience. Qualitative changes in the content of systems of knowledge are not necessarily expressed in the successive replacement of the means of their objectification: as a rule, that is exactly what does not happen.

p Reading a text (if "text" is taken to mean any mode of objectification of knowledge, and "reading"—any form of its interpretation by the subject) always implies differentiation between the semantic content embodied in it and those specific traits of the material of implementation which do not have the function of differentiating meaning. In practice, this differentiation is usually subconscious, so that what is directly given to the subject is the semantic content of knowledge, that is, what the text says about the real objects themselves. Modern linguistics draws a clear distinction between the value of a language unit and the material of which it is built. The material of different units 211 may vary while their values expressed in interrelations are constant. When a person hears someone’s speech (and this case may be included in reading a text in the broad sense accepted here), only the content rendered by that speech is given to consciousness and not the way sounds are pronounced or the separate sounds themselves. (That is, on condition, of course, that all the existing variations in pronunciation do not go beyond the limits where the meaning will be distorted.) In reading a printed text, I do not notice separate letters, the kind of paper on which the text is printed, I can miss a misprint, for consciousness is at that moment directed at reproduction of semantic connections. If my task is searching for misprints, however, the perception of the given text is quite different: working as proof-reader, I cannot grasp the meaning of the semantic phrases reified in the text. Basically the same thing happens on decoding any semantic content objectified in some form or other. For example, if I perceive a work of art, I do not see the canvas or the paint spots but the content expressed with their help. Even "reading" photographs, which at times appear as good as "natural replicas" of the real objects, is only possible if one ignores the quality of paper, the fact that the picture exists in two dimensions, unlike the three-dimensional real objects, and that the objects in the picture are motionless while in the world of real objects all kinds of changes continually take place, etc.

p Singling out the properties which have the function of sense differentiation in the means of objectification of knowledge, and distinguishing them from the characteristics indifferent to meaning, are not determined by any physical properties of these objects directly given in their bodily form. This singling out is entirely determined by the culture in which the given objects function. If one has not assimilated this culture and has not mastered the modes of communication accepted in it, one is incapable of expressing the semantic content objectified in the mediator objects. Speech in an unfamiliar language is perceived as a jumble of sounds, a scientific text in which unknown terms and systems of symbols are used appears as an agglomeration of incomprehensible signs, etc. Even works of art and sculpture that are aimed at presenting reality in the form in which it is ordinarily perceived, can be correctly "read" only if we have mastered the language of art, that is, in particular, if we take into account the specificity of the given style, the modes of presentation accepted in it, etc.

p However, the fact that the physical properties of the 212 mediator objects do not directly determine the functional role they play as instruments of objectification of knowledge, does not at all mean that the former are completely indifferent to the latter. They are independent of each other only within certain limits. The need for expressing basically new cognitive content may in some cases produce the requirement for other types of mediator objects, those whose physical properties would be more adequate to the solution of the given task. These mediators make it possible to express in knowledge a new system of objective meanings,of such aspects of the real world which it would be hard to grasp and express in terms of the existing means. The discovery of new types of mediators signifies the rising of cognition to a new content level. Of this nature is, for instance, the transition from gesture language directly linked with object-related activity to sound language, or the transition from oral to written speech.^^84^^ (Written speech creates new possibilities for reconstructing the object in its entirety. The development of science is obviously impossible without writing.)

p Absolutely identical content cannot be rendered in terms of different types of objectification of knowledge. We have already noted that verbal formulation of the content of perception introduces something new in knowledge. This kind of alteration of content happens even where there is apparently nothing but mere copying. If an artist paints from life, he is compelled to take into account the properties of the material in which he embodies his work, the specific properties of paints (which are always different from the colour characteristics of the real world), and the modes of artificially creating an impression which would recall in some important aspects the impression in ordinary perception (which is an important condition of realistic art) and at the same time essentially deepen the latter. Ordinary perception and a work of art represent two different systems of content rendering. The content itself cannot therefore be absolutely identical. The potential of painting is not indifferent to the specific features of the material which is used in it as a means of content objectification. The history of this art is among other things also the history of experimenting with the material itself for establishing its representational potential, it is a search for the modes of reflection which are not directly prompted by mere perception of the object painted. A person that cannot draw cannot represent a familiar object on paper. The ability itself is not attained through spontaneous development but through learning in which cultural-historical 213 experience is transmitted. The latter varies in different cultural Tegions and at different stages of the artistic and cognitive development of mankind. The possibility of "drawing from nature" thus assumes that the subject is included in a specific, system of mediator objects, that is, he can operate with them according to definite rules. It is therefore extremely difficult to draw an object for which no modes of representation have been worked out in the give^cultural tradition. E. H. Gombrich convincingly illustrates this point citing a mass of data from the history of art.^^85^^

Thus, the emergence of new systems of mediator objects also marks the appearance of new cognitive possibilities, of other worlds, in a sense. In this case, too, however, there is no complete disruption of continuity of cognitive experience, there are no alternative worlds absolutely excluding one another and mutually impermeable: it is rather a matter of enriching experience with qualitatively new content expressing previously unknown aspects of objective reality.