  Fuzziness and randomicity widespread exist in natural science, engineering,
technology and social science. The purpose of this paper is to present a new
logic - uncertain propositional logic which can deal with both fuzziness by
taking truth value semantics and randomicity by taking probabilistic semantics
or possibility semantics. As the first step for purpose of establishing a logic
system which completely reflect the uncertainty of the objective world, this
logic will lead to a set of logical foundations for uncertainty theory as what
classical logic done in certain or definite situations or circumstances.
