PRINCIPLES OF UNCERTAINTY - WHAT ARE THEY - WHY DO WE NEED THEM

The meaning and utility of three principles of uncertainty is discusse d. These principles, which are referred to as a principle of minimum u ncertainty, a principle of maximum uncertainty, and a principle of unc ertainty invariance, depend on the theory in which uncertainty is conc eptualized. Due to a connection between uncertainty and information, t he principles may also be conceived as principles of information. To m ake the principles operational in a particular uncertainty theory, we need to measure the amount of relevant uncertainty (and associated inf ormation) in each problem situation describable within the theory. Wel l-justified measures of uncertainty have thus far been established onl y in some uncertainty theories. These theories, their uncertainty meas ures, and the associated uncertainty principles are overviewed in the paper.