Some Perspective on the Higgs Boson

The discovery of the Higgs Boson is an great success for the Standard Model of particle physics. The Standard Model explains the properties of light; the particles that make up atoms; the slew of other particles that appear for fleeting moments common particles collide, and three of the four fundamental forces in physics (electromagnetism, the weak nuclear force, and the strong nuclear force). It is one of the most well-tested theories in science. Nonetheless, after decades of testing, one key prediction of the Standard Model had yet to be tested. Physicists had not yet confidently detected the Higgs Boson, a particle hypothesized to interact with quantum fields to give other particles mass. As of today, though, physicists working at the Large Hadron Collider have announced that something looking exactly like the Higgs Boson exists. With this, the last prediction of the Standard Model has come nearly to fruition.

Discovering the Higgs Boson is also a fantastic validation of the scientific method. Thomas Kuhn summarized how science works in his Structure of Scientific Revolutions. Most of work in science is spent probing scientific paradigms like the Standard Model, in order to confirm that the various predictions within the paradigm are correct. The search for the Higgs Boson, and before that for the W and Z bosons (found in 1983) and the top quark (found in 1995) , fit perfectly into Kuhn's interpretation of scientific work. Theoretical physicists worked out the implications of their theory, and predicted new particles. Experimental scientists then designed and built experiments that would be able to infer that the particles existed. Finding the Higgs registers as a great success for the hard work of science, because physicists found what they were looking for.

Finding the Higgs Boson also is an enormous triumph for the Large Hadron Collider (LHC). Measuring the Higgs Boson (or ruling out its existence) is one of the main goals of the LHC. The LHC will hopefully still make other discoveries - it might find evidence for a slew of additional "supersymmetric" particles, or hints of extra dimensions - but none of those are required by currently accepted theories. Therefore, building a $9 billion experiment just to look for them would have been risky, and possibly controversial. The search for the Higgs justified the LHC. Finding the Higgs validates the design decisions that went into building the LHC.

So, the Higgs Boson justifies our continued use of the Standard Model; it gives us confidence in the scientific method; and it can be used to justify the building of the Large Hadron Collider. However, there is a real sense in which the Higgs Boson poses a problem for physicists.

This is captured well in a piece in Wired, How the Discovery of the Higgs Boson Could Break Physics. The problem is that in science, the only way to push theories into truly new territory is to discover the ways in which they are wrong. Scientists already have a lot of reasons to believe the Standard Model is wrong. It's quantum mechanical nature cannot be reconciled with the smoothly-curved space-time of General Relativity. It provides no explanation for the origin of the dark matter that appears to holds galaxies together. It also provides no explanation for the dark energy that is causing the expansion of the space-time of the Universe to accelerate. Finally, the model includes several "free parameters," or numbers that have to be assigned arbitrarily to explain the masses of some particles and the strengths of the fundamental forces. Finding the Higgs Boson does not help address any of those problems, and it closes off one possible route to discovering something new.

The Big News discovery of the Higgs Boson has also led to media reports that distort the meaning of the discovery. I'm afraid this is because some clever physicist decided to call the Higgs Boson "the God Particle," and it stuck. It probably seemed like a good marketing move, but in the end it suggests the particle has an outsized importance in the theory.

The New York Times called the particle a Holy Grail, which I guess is meant to reflect the fact that the discovery is a Big Deal. I have a personal dislike of that hackneyed phrase, but I would also object because, as I said above, the really big deal would be the discovery of something unexpected.

Both The New York Times and The Daily Beast referred to the Higgs Boson as a Key to Life. Even an otherwise informative and well-written essay in Science News took this tack:

In fact, the Higgs is responsible for the structure of the universe as we know it. It's the Higgs that makes physical reality the way it is, with atoms, chemical reactions and life. No Higgs, no molecules. No planets. No people.

While that's technically true, this is misleading in a few ways. First, the paragraph ignores the philosophical distinction between the reality of our Universe and physicists' model for the Universe. Our existence is a given. The Standard Model is how we try to understand the facts of our existence. If the Higgs Boson had not been found, it would not have undermined reality, but our model.

Second, the paragraph implies that the Higgs Boson is the key to everything in the Standard Model. In fact, it is no more central to the Standard Model than any other particle, field, or force. That paragraph could have as easily read, "The electron is responsible for the structure of the universe as we know it..." If the Higgs had turned out not to exist, reality would not have been affected. Instead, we would have found that our model was not a complete description of the Universe. The Higgs is not special because nothing works without it (that's true of all the particles), but because it was the last particle to remain undiscovered.

Finally, there seems to be a mistaken notion that physicists have come closer to understanding the nature of life by finding the Higgs Boson. This, to me, is laughable. Physicists understand how individual particles interact with each other, in pairs and groups of a few. Physicists now have access to the computational power to approximately understand simple molecules. However, physicists are still generally flummoxed when they try to calculate how proteins fold. Physicists are almost completely lost when they try to understand life. True, they can measure the structure of DNA, and contribute to decoding the genome, measure the electrical chemical reactions in neurons, examine the balance of hormones, and determine how the blood transports oxygen. However, having models for the components of a living being is not the same as understanding life. The interesting parts of life are not addressed by finding the Higgs Boson: understanding how life originated, how it became so diverse and complex, how it developed consciousness.

Finding the Higgs Boson is a big accomplishment for particle physicists. It is, however, just a small step for understanding.