Friday, December 21, 2012

Maybe Reality Is Not An Infinitely Peelable Onion?

Science is the search for rational understanding of nature and the universe achieved through replicable observation.  2012 has seen a fundamental advance in the effort to achieve an ultimate understanding of physical reality and the cosmos with the discovery of the Higgs boson.  In July, the Large Hadron Collider (LHC) in CERN found direct evidence of the Higgs.  Since then, further LHC data appears to place the Higgs more firmly in the Standard Theory that unifies three of the four fundamental forces (electromagnetic, weak, strong and gravity).  Perhaps equally significant, however, is what LHC seems not to be finding - evidence supporting Supersymmetry, the only candidate theory physics has to unify all four forces and explain the dark matter that seems key to holding galaxies together.

Supersymmetry posits an unseen partner particle for every particle now known to science.  Supersymmetry is a basis for string theory, which directly seeks to account for quantum gravity.  With evidence for supersymmetry and string theory, we would have a unified theory of forces and particles, uniting the big and the small and explaining "everything."

Trouble is that those particles that LHC could be finding if the simplest versions of supersymmetry were predictive don't seem to be there.  This does not rule out more complex versions of the approach but modern physics has generally been guided by the notion that the simple is most beautiful and the beautiful is more likely to be true.

But its not the details of the current state of physics that I want to talk about here but the very quest for an ultimate understanding, one that explains everything we can see and know by some set of fundamental scientific laws and equations.  The notion that everything has an ultimate explanation, according to a laws-based structure that puts everything in its place, cannot logically be true.  Any explanation of what is by another set of what-ises begs the question of what explains those.  Gödel’s Incompleteness Theorem puts this nicely:  “Anything you can draw a circle around cannot explain itself without referring to something outside the circle – something you have to assume but cannot prove.”

The menagerie of particles now known by science includes all sorts of particles with mass (fermions) and those without (bosons).  The smallest fermions include quarks and leptons.  Supersymmetry and string theory seek to explain all these particles by placing them within a frame with many other particles and dimensions that we cannot observe and for which we so far have no evidence.  Meanwhile, an extension of string theory - superstring theory - seeks to explain the Big Bang and space-time by positing other things we cannot observe:  colliding branes.

Let's suppose that we find evidence of some form of the supersymmetry and superstring theories, i.e., that they are "true."  What will explain them?  What will account for whatever laws and equations that seem to predict everything else we can observe?  Where do the laws that govern lawful action come from?  As Gödel proved, nothing can explain itself.

Perhaps, Plato was right.  The cosmos is made up of Forms.  What if the basic building blocks of existence - the bosons and fermions we observe, the structure of space-time, the Higgs field that creates mass, the gravity that pulls mass so tightly that it releases the energy of life in the middle of our sun - all these, just are? 

The explanation of everything is either infinitely recursive - each peel of the onion of explanation simply uncovers the next layer to be explained - or the ground of everything is/was simply there.  Either way, it makes science no less important and useful but not necessarily the answer to all questions and especially to those most human of all questions - why are we here, where do we come from and for what ends?

1 comment:

Anonymous said...

Humans, and our beginning to explore rational thought and science put us very near the outer edge of the onion, or whatever metaphor works to describe our exciting and accelerating journey of discovery. The questions are as interesting as the answers. I just wish I could live long enough to see a few more answers than questions.