ABSTRACT
Quantum mechanics is a revolutionary theory of the motion of physical objects in space and time. It was built up through the accumulation of new ideas after the turn of the twentieth century, and reached mathematical maturity roughly a quarter of a century later. Since this early beginning, physicists and philosophers have grappled with its broad and deep philosophical meaning. A number of different interpretations of the theory, which have differing philosophical emphases, have been offered. The world picture that quantum mechanics provides differs dramatically from that of all previous theories of physics, in several respects. This is so regardless of which of the several available interpretations of its formalism one considers. The quantum world picture differs from its predecessors most significantly in the
following respects: the way that objects can be described individually; how definite such individual descriptions can be; the way that the parts of objects are related to the larger wholes they make up. Important questions regarding this quantum world picture remain incompletely resolved. These include how the behavior of physical objects can be explained using the principle of causation. This question must also be reconciled with the theory of space and time, that is, relativity. Although the world picture provided by quantum mechanics can be highly counter-intuitive, it is the most successful theory in the history of physics and remains essentially unrivaled. One thing that made quantum mechanics a revolutionary physical theory relative
to its predecessors is that the descriptions it provides of physical objects and processes are limited in specific ways. The descriptions given by those previous widely accepted physical theories are not. In particular, its descriptions differ from those of its immediate and very intuitively understandable predecessor, classical mechanics. Classical mechanics is the description of motion and behavior of objects in the tradition established by Isaac Newton. Classical theory puts no fundamental limitation on the description of objects. In quantum mechanics, both the simultaneous specification of the properties of objects and one’s ability to make precise simultaneous measurements of these properties are limited in a way that can be mathematically specified.
