In the Beginning was Information

9 The Quality and Usefulness ofInformationShannon’s information theory can be regarded as an extension ofprobability theory. He takes the bit as unit of measurement ofinformation, and a book with 200 pages then contains twice asmuch information as one with 100 pages if the pages contain thesame number of letters. Meaning is completely ignored. WolfgangFeitscher gave a striking description of this situation: “When consideringsemantic information, we are like a chemist who canweigh substances, but cannot analyse them.” In this sense Shannonsolved the problem of weighing information, but the analysis questionis still untouched. To rise above Shannon’s theory, it is necessaryto define measures for semantic information which must begenerally valid. We will now discuss some aspects which may pavethe way for solving this difficult problem.A semantic measure would not be a measure of quantity but ofquality. It could happen that a book comprising several volumesmay have a lower semantic evaluation than a thin brochure. A qualitativeevaluation of information involves some parameters whichdepend very strongly on a subjective appraisal, and this has anappreciable aggravating effect on the problem. Figure 25 depicts agraph of the semantic value of information with respect to its usefulness.There are five value levels:1. Extremely important information: This is the highest levelbecause of its high apobetics content (e. g. essential and vital information).2. Important information: Information which is required forachieving some purpose (e. g. knowledge of planned routes, telephonenumbers, address lists, and subject knowledge).3. Useful information: This includes information which is of generalvalue in the sense of being informative, constructive, edifying,or amusing (e. g. daily news, weather reports, general increase ofknowledge, and novelties).116