Neo-quantum theory

Michael E. Cuffaro

I distinguish two senses in which one can take a given physical theory to be `complete'. On the first, a complete physical theory is one that, in principle, completely describes physical reality. On the second, a complete physical theory is one that provides all of the conceptual resources one needs to describe any (in general probabilistic) physical phenomenon to any level of detail one likes, in principle. I argue that while the (neo-)Everettian approach to interpreting quantum mechanics aims to show that it is complete in the first sense, the (neo-)Bohrian approach begins from an understanding of quantum mechanics as being complete in the second sense. I then discuss some of the essential differences between how classical and quantum theory describe phenomena, and the way in which the quantum description can be thought of as a ``natural generalisation'' (to use Bohr's phrase) of the classical description. Finally, I elaborate upon the two visions of physics from which one can motivate the first and the second sense of completeness, respectively: \emph{metaphysical realism}, on the one hand, and what I will call \emph{methodological realism}, on the other -- and discuss what one can say about the significance of the differences between quantum and classical description from each of these points of view. I suggest that there is a sense in which the views of (neo-)Everett and the views of (neo-)Bohr can be understood to be mutually supporting positions, from their respective perspectives, even though they are diametrically opposed.

Woon Siong Gan

Peter Stuart Mason

Foundational attitudes towards quantum theory have recently thrown off much of the old philosophical baggage largely associated with Niels Bohr to which Einstein famously objected, including the central ‘collapse of the wavefunction’ concept. A ‘neo-Copenhagen’ interpretation, it is suggested, has arisen. This development is placed in its historical context and contrasted to philosophical allegations of anti-realism. The neo-Copenhagen interpretation remains wedded to Heisenberg's uncertainty and observer-dependent values of particles. However a discussion of Nick Herbert's ‘rainbow analogy’ suggests that subatomic particles are emergent from a ‘nonlocal’ level of reality outside the domain of space and time. Critical realism recognizes that emergent systems have an irreducibly ontologically character, and in its combination of epistemological relativism and ontological realism, provides a basis for the proposition that realists who support Einstein's objections must now recognize that their realism must be redefined.

Peter Atkins, Julio de Paula, James Keeler

M. Anthony Mills

Rick Ubic