Knocking on Heaven's Door - Lisa Randall [126]
The basic problem with the identification of truth and beauty is that it does not always hold—it holds only when it does. If truth and beauty were equivalent, the words “ugly truth” would never have entered our vocabulary. Even though those words weren’t specifically directed toward science, observations about the world are not always beautiful. Darwin’s colleague Thomas Huxley nicely summarized the sentiment when he said “science is organized common sense where many a beautiful theory was killed by an ugly fact.”59
To make matters more difficult, physicists have to allow for the disconcerting observation that the universe and its elements are not entirely beautiful. We observe a plethora of messy phenomena and a zoo of particles that we’d like to understand. Ideally, physicists would love to find a simple theory capable of explaining all such observations that uses only a spare set of rules and the fewest possible fundamental ingredients. But even when searching for a simple, elegant, unifying theory—one that can be used to predict the result of any particle physics experiment—we know that even if we find it, we would need many further steps to connect it to our world.
The universe is complex. New ingredients and principles are generally needed before we can connect a simple, spare formulation to the more complicated surrounding world. Those additional ingredients might destroy the beauty present in the initial proposed formulation, much as earmarks all too often interfere with a congressional bill’s initial idealistic legislation.
Given the potential pitfalls, how do we go about trying to go beyond what we know? How do we try to interpret as-yet-unexplained phenomena? This chapter is about the idea of beauty and the role of aesthetic criteria in science, and the advantages and disadvantages of beauty as a guide. It also introduces model building, which uses a bottom-up approach to science, while paying attention to aesthetic criteria in attempts to guess what comes next.
BEAUTY
I recently spoke with an artist who humorously remarked how one of the great ironies of modern science is that today’s researchers seem more likely than contemporary artists to present beauty as their goal. Of course, artists haven’t abandoned aesthetic criteria, but they are at least as likely to talk about discovery and invention when discussing their work. Scientists cherish those other attributes too, but they simultaneously strive to find the elegant theories they often find most compelling.
Yet despite the value many scientists place on elegance, they can have divergent notions about what is simple and beautiful. Just as you and your neighbor might violently disagree over the artistic merits of a contemporary artist such as Damien Hirst, different scientists find distinct aspects of science satisfying.
Together with like-minded researchers, I prefer to search for underlying principles that illuminate connections among superficially disparate observed phenomena. Most of my string theory colleagues study specific solvable theories in which they use difficult mathematical formulations to tackle toy problems (problems not necessarily relevant to any real physical setup) that might only later find applications to observable physical phenomena. Other physicists prefer to focus only on theories with a concise elegant formalism that generate many experimental predictions which they can systematically calculate. And others simply like computing.
Interesting principles, advanced mathematics, and complicated numerical simulations are all part of physics. Most scientists value all of them, but we choose our priorities according to what we find most pleasing or most likely to lead to scientific advances. In reality, we often also choose our approach according to which method best suits our unique inclinations and talents.
Not only do current views of beauty vary. As is also true with art, attitudes evolve over time. Murray Gell-Mann’s own specialty, quantum chromodynamics,