The emergence of quantum mechanics has been a huge challenge to Materialism. Particularly, both the mathematical models and results of the double-slit and quantum erasers experiments suggest that material reality only exists when it is being measured or observed. These particles cannot have a precise location and momentum until an unentangled observer conducts a measurement on the system. Prior to measurement there is a range of uncertainty that is inherent in the system.
There are three major classes of interpretations: The Copenhagen which asserts that reality is a wave described by the Shrodinger equation until the wave-function is collapsed by measurement; the many worlds interpretation which asserts that each change of quantum state is the multiplication of different worlds, or Bohmian mechanics. This article will focus on Bohmian mechanics.
Bohmian mechanics asserts that particle actually exists in a precise position that is predetermined by pilot waves that are generated by the total configuration of every other particle in the universe1. Bohmian mechanics posits that there is no actual uncertainty in a quantum system; the uncertainty is only a function of our lack of knowledge of all of the variables - particularly our inability to ever detect the pilot waves that control configuration of particles in the universe.
In Bohmian mechanics the pilot waves are non-local. Locality means that for one object to causally affect another object in the same space, it must act through every point of space between the objects. Non-locality involves the ability of an object to skip the space separating it from another object. Imagine that our three dimensional space is compressed into a sheet of paper. Folding one corner of that paper onto any spot on the paper. An object on that corner can affect non-local action on an object on any spot of the paper that corner touches. An object that transcends the dimensions of that space, in this case my finger, can also affect non-local action on an object inside that space.
A little introductory weirdness
If pilot waves are produced by every particle in existence, and every particle is defined by every other particle; then every event - no matter how insignificant or how seemingly irrelevant - has at least some causal influence on every other event. For example, my decision to eat a Big Mac in the summer of 2008 might have made the difference in deciding whether Obama won or McCain won the presidency. It is also possible that the last I passed gas that it tilted the causal scale that caused someone in China to die of a heart attack.
This weirdness is not limited to space. Relativity describes space as containing time as a fourth dimension. This is called Minkowski space-time or simply space-time2. While there is much more limited knowledge of non-locality of time in quantum mechanics, there has been limited observations of such non-locality3. Additionally, the description of space in relativity as including time as a fourth dimension would suggest that non-locality of space would also include non-locality of time as well.
If space includes time as a fourth dimension, then the entire universe would include all of time. The generation of pilot waves by the configuration of every particle in the universe includes every moment of time. Does this mean that that my mom feel in love with my dad because I love Mexican food? It would necessarily mean that. It might be objected that it plays such a tiny, tiny role. If EVERY particle contributes to the pilot waves that defines every other particle, then even the most obscure and seeming irrelevant events have some causal influence on any given event.
From weirdness to absurdity
If can causally influence my parents decision to become a couple, that does not take away the necessity that their coming together had a huge causal influence in my coming into existence on this physical world. Given Bohmian mechanics, my creation was a circular event. My actions influenced actions which then caused me to exist. This circularity often comes up in time travel paradoxes. (i.e what happens if someone murders their grandparents before their parents were born. Such circularity is a defeater because ultimately nothing is sufficient to explain anything. A depends on B, but B does not exist because it depends on A; since B does not exist, neither can A.
In Bohmian mechanics this circularity is not limited to particular paradoxes, but consumes the whole universe. If every element is defined by the configuration of every other element, and all of those elements depends on every other element that depends on them, then ultimately nothing can be defined and nothing can exist in any configuration. Bohmian mechanics cannot account for itself.
1 Quantum Weirdness Replaced by Classical Fluid Dynamics
From the article: “ In the de Broglie-Bohm Interpretation, quantum events are inherently nonlocal: because the vector of any one particle is a function of the pilot-wave, which depends on the global configuration of the entire universe ”
2 A Space-Time Cocktail: Minkowski Space and Special Relativity
3 Nonlocality With Time Reversibility