Information can be defined in different ways:

• as knowledge obtained from investigation, study, or instruction;
• as a signal or character (as in a communication system or computer) representing data;
• as a quantitative measure of the content of information;
• as data at any stage of processing (input, output, storage, transmission, etc.);
• as something (such as a message, experimental data, or a picture) that justifies change in a construct (such as a plan or theory) that represents physical or mental experience or another construct. (1)

The last of these definitions serves our purposes best. (Next page)