Against the Copenhagen Interpretation
I’ll get around to quantum mechanics eventually. Bear with me.
Biology is autonomous from physics. Any change to quantum mechanics will have at most cosmetic implications for biology. Quantum mechanics contributes nothing more than the existence of atoms and molecules, which are necessary for the lossless transmission of information. However, anything that replaces present day quantum mechanics must also predict atoms and molecules. The interactions between the two subjects a minimized because their interface is pinned by experiment.
Within physics, thermodynamics, fluid mechanics, elasticity, and the other macroscopic theories bear the same relation to quantum mechanics. The interfaces between the subjects are experimentally pinned.
A similar pattern appears within biology. Population genetics is built on molecular biology, but their interface is pinned by the existence of genes. We can replace our understanding of an allele’s molecular character, but that allele’s propagation in a population isn’t going to dramatically change.
This pinning is a form of damage control. All fields of science depend on other fields to be able to bootstrap themselves. The only way to keep the structure from falling to shreds is to pin the interfaces. A particle physicist uses macroscopic equipment, which experimentally obeys classical mechanics and electromagnetism. If the relation between his equipment and what he studies weren’t experimentally fixed in the intervening scales, his experiments would be impossible.
It is worth keeping your field as self contained as possible. Black boxes that reach into the heart of entirely different fields are a recipe for disaster.
This is why I dislike the Copenhagen interpretation of quantum mechanics. It posits an observer, whose observation collapses the wave function to an eigenstate of the observation in question. In so doing, it reaches directly to the heart of neuroscience, and builds quantum mechanics on the hardest, most central questions of an even larger area of science.
If the neuroscientists come up with the answer that consciousness isn’t anything special, just a pattern of spikes in neurons, then we have an insoluble problem. Further, there isn’t likely to be a physically robust structure of these firings which is consciousness, so what’s to stop other random patterns of particles from observing and collapsing wave functions? These difficulties are so great, that any interpretation — that is, a connection of the undisputed mathematical structure to reality — which is properly pinned at its boundaries are immediately preferable.
Yet most physicists aren’t willing to accept a new interpretation which requires conceptual gimmicks. Visualizations are tools with local use, not integral parts of theories. Since Heisenberg, we want our theories only to relate observable quantities, not enforce a particular picture. This was the great downfall of the Bohm-de Broglie pilot wave mechanics.
Thankfully, there is an interpretation which is both properly pinned and satisfies the Heisenberg aesthetic. There’s a beautifully written, absolutely simple book on it (Consistent Quantum Mechanics by Robert Griffiths). The book is available for free online.
madhadron :: Nov.28.2007 :: physics, teaching :: 1 Comment »
One Response to “Against the Copenhagen Interpretation”
Discovered your site this morning, upon having ‘googled’ the phrase, “damnation by faint praise” — for purposes of confirming or refuting Shakespeare as its source. (I’m suitably embarrassed by my lack of culture, etc, etc. For completeness’s sake, I’ll state that my ‘final purpose’ is to use that phrase in a quite positive review of Graham Hutton’s ‘Programming in Haskell.’) There is much that Alfred O’Rahilly (Electromagnetics, 1938) is wrong about, including his theory of E&M; however, he’s dead right when he says, “Physics cannot solve philosophical problems.” Hear, hear. You’re right about Copenhagen. I felt quite cheated when, almost 45 years ago, the very smart (late) Professor Gerald Feinberg overloaded the Advanced QM final with Copenhagen-type and EPR-paradox philosophical questions. And here I wanted to come to grips with calculating renormalization & the Lamb shift. I hope not to sound as if I’m slouching toward Philipp Lenard, whose motive was not better physics, and whose diatribe Jack Steinberger asked us to translate as one of two foreign-language requirements for the PhD.
Thanks for some great ‘reads,’ and sorry for my exercise of Proustian tendencies.
– George