Knocking on Heaven's Door - Lisa Randall [128]
This story has repeated itself many times since. Beauty is often agreed on only a posteriori. Weak interactions violate parity symmetry. This means that particles spinning to the left interact differently from those spinning to the right. The breaking of such a fundamental symmetry as left-right equivalence seems innately disturbing and unattractive. Yet this very asymmetry is what is responsible for the range of masses we see in the world, which is in turn necessary for structure and life. It was considered ugly at first, yet now we know it is essential. Although perhaps ugly in itself, parity symmetry breaking leads to beautiful explanations of more complicated phenomena essential to all the matter we see.
Beauty is not absolute. An idea might appeal to its creator but be cumbersome or messy from someone else’s perspective. Sometimes I’ll be quite taken with the beauty of a conjecture I’ve come up with largely because I know of all the other ideas people had thought of before that hadn’t worked. But being better than what came before doesn’t guarantee beauty. Having made my share of models that satisfied this criterion, but were nonetheless met with skepticism and confusion from colleagues who were less familiar with the topic my model addressed, I now think a better criterion for a good idea might be that even someone who never studied the problem can recognize its appeal.
The reverse is sometimes true as well—good ideas are rejected because their inventors consider them too ugly. Max Planck didn’t believe in photons, which he thought to be an unpleasant concept, even though he initiated the train of logic that led to their conjecture. Einstein thought the expanding universe that followed from his equations of general relativity couldn’t be true, in part because it contradicted his aesthetic and philosophical predispositions. Neither of these ideas might have seemed the most beautiful at the time, but the laws of physics and the universe in which they applied didn’t really care.
LOOKING GOOD
Given the evolving and uncertain nature of beauty, it’s worth considering some of the features that might make an idea or an image objectively beautiful in a way that has some universal appeal. Perhaps the most basic question about aesthetic criteria is whether humans even have any universal criteria for what is beautiful—in any context—be it art or science.
No one yet knows the answer. Beauty, after all, involves taste, and taste can be a subjective criterion. Nonetheless, I find it hard to believe that humans don’t share some common aesthetic criteria. I often notice a striking uniformity in people’s opinions about which piece of art in a given exhibit is the best or even which exhibits people choose to go see. Of course this doesn’t prove anything since we all share a time and place. Beliefs about beauty are difficult to isolate from the specific cultural context or time period in which they originate so it’s difficult to isolate innate from learned values or judgments. In some extreme cases, people might all agree that something looks nice or appears unpleasant. And in some rare instances, everyone might agree on the beauty of an idea. But even in those few cases, people don’t necessarily agree about all the details.
Even so, some aesthetic criteria do appear to be universal. Any beginning art class will teach about balance. Michelangelo’s David in the Accademia Gallery in Florence exemplifies this principle. David stands gracefully. He’s never going to tip over or fall apart. People search for balance and harmony where they can find it. Art, religion, and science all promise people the opportunity to access these qualities. But of course balance might also be simply an organizing principle. Art is also fascinating when it defies our notions of balance, as we see in early Richard Serra