Letting Go of Common Sense

I spent my first three decades learning how to do physics, and the next four trying to understand it. Doing physics was merely difficult, but understanding it seems impossible. As noted elsewhere, anyone who believes that they understand quantum mechanics has obviously not studied it very well. The fact that the theory works is unquestionable; it makes precise predictions about physical properties that have been measured to be accurate within (at least) one part in 1,000,000,000,000.  But it does this at the expense of treating particles of matter as though they do not possess actual locations or well-defined motions, but only some amalgamation of the two that does not really exist until someone decides to measure one or the other. Since the ultimate test of theory is physical measurement, the outstanding accuracy of quantum theory seems unlikely to ever require an alternative explanation. It is “common sense” that has been shown to be the least reliable way of interpreting reality.

The unreliability of common sense should not be surprising. Human brains evolved to become adept at perceiving and surviving their everyday environment; accurate perception about the workings of quantum particles, galactic encounters, or the origins of the universe was never a requirement for survival. The triumph of science over the past 500 years has been due to the acceptance that the ultimate test of a theory is that it makes correct predictions/descriptions of physical observations that can be made and measured by other observers, regardless how outrageous the theory seems. Our human intellect and intuition has repeatedly been humbled in the face of this requirement.

A common misunderstanding is that scientific knowledge never progresses, but only changes from time to time, as new theories invalidate and replace the old ones. This seems true only if one takes the position that a physical theory should represent “actual” reality, rather than to describe how the universe works. Within the accuracy of measurements available at the time, the Ptolemaic solar system and Newtonian physics made adequate predictions. Only when measurement capability became more sophisticated, quantifying the behaviors of stars, atoms and photons with high precision, were the classical theories found to be inaccurate.

The changes that were needed to make the theories match the measurements have altered our viewpoints on reality in directions that seem incomprehensible; four-dimensional space-time curvature replaced gravitational force, time flows at different rates in different circumstances, and empty space is seething with virtual particles whose existence is temporary. These concepts are not just speculations, but are required in order to make the models mathematically consistent with the measurements. Which is all that we can do. To believe that our models now represent absolute reality is foolish, because our brains are finite and limited to the concepts of our experience. The universe may, in fact, be infinite in space and time.

My own attempts to contemplate an infinite universe with no beginning always produce slight dizziness and nausea. But it is consistent with the mathematics, and the universe has always been found to mathematically consistent. If fact, advanced mathematics has been the one true guide to discovering the nature of physical reality:  from calculus through tensor algebra, multidimensional vector spaces, group symmetries, and the topological properties of Calabi-Yau manifolds which currently underpin string theory. It's not an easy language to learn.

I occasionally see articles predicting the death of the Big Bang model of creation, based on current speculations about multiverses within the cosmological community. These articles are written by non-scientists. Even though science has gathered a reputation for fickleness in its faithfulness to models, the Big Bang is currently in no danger of being replaced by a more accurate version. It has not been contradicted, but strengthened, by increasingly accurate measurements from satellites and telescopes. We understand the first few seconds of the universe in much better detail than we understand the current one. It was much simpler back then.

What is now happening is that many physicists are frustrated by the apparent fine-tuning of our universe, in its gradual evolutionary buildup of stars, galaxies, elements, planets, molecules, organic matter, living organisms, consciousness, and intelligence. It seems a very unlikely and well-ordered progression, and one that would have been impossible if the forces of the universe would have differed in the slightest from what they have been measured to be. And we don’t know what causes those forces to take on the values that they do.

Without recourse to a very intelligent designer for our universe, one possible explanation is that there are many other universes that have also randomly appeared, wherein the randomly-generated force constants have taken on many different combinations, but no universe different from ours would have ever generated life. We’re just the lottery winners, although the players in other universes never got the opportunity to exist. Unless there really are an infinite number of other universes, in which case there are lots of other universes with intelligent life, many exactly like ours.

The multiverse theory in no way contradicts the Big Bang origin of our universe, but is an attempt to answer a question about what happened “before” the Big Bang, and why our universe is so perfect. In my mind, it is less about physics than philosophy, because it seems impossible to make measurements that could verify the existence of other universes outside our own space-time.

One great pleasure and satisfaction of studying science is in the growing awareness of the complexity, interdependence, and inevitability of the evolutionary processes that have created our existence. While we have some knowledge about the sequence of evolutionary events that led here from the Big Bang, we still have no basic understanding of how the complexity of conscious beings emerged from the maelstrom of baryons and leptons that comprised the early universe.  One might expect- in order for entropy to increase- that organized states should devolve into less organized states, so that complex sequences of molecules could never have been generated spontaneously, much less continue to organize into cells, organisms, and thinking creatures. But evolve and organize they do.

Classical thermodynamics is based mostly on the behavior of systems that are near to equilibrium, i.e. a state of maximum probability and disorder, where energy flows have ceased. It is toward such equilibrium that systems eventually evolve, and our physics describes accurately how the resultant evolution and energy flow proceeds. What has not yet been well-studied is the evolution of systems that are far from equilibrium, where large flows of energy are still occurring, for example a planet being bathed in radiation from a star.  In such conditions, entropy can still increase via heat flows, while organization and complexity continue to increase.

These are metastable states- not yet maximized for entropy nor minimized for energy- but stable while the energy flows continue. If science is to understand the spontaneous evolution of complex forms within the universe, it seems that we need much better descriptions of nonlinear thermodynamic systems exchanging energy under conditions far from equilibrium. Long-range order arising from near-term interactions seems to be a common feature among galaxies, ocean waves, brains, and societies. It would be nice to know how this comes about, even if we don't really understand it. If you know what I mean.