This article offers a conceptual analysis of the famous Heisenberg relations, usually referred to as "the uncertainty principle". After a brief historical introduction, it is pointed out that the relations can be interpreted in three entirely different ways. It is shown in some detail how each interpretation derives from a distinct basis, and leads to distinct physical and philosophical consequences.
Heisenberg relations; uncertainty principle; quantum indeterminacy; Heisenberg; Bohr; Einstein; Popper
