String Theory Appeals to Authority
In the case of string theory, of course, the authority figures aren’t just popular, they are experts in physics, and string theory in particular, so listening to their opinion on string theory is a bit more reasonable than listening to a single popular actor, musician, athlete, or clergyman on whom to vote into the presidency.
Although it may seem odd to many people that scientists could be swayed by figures of authority, this is a fundamental part of human nature. The appeal to authority was cited by Aristotle, the father of rhetoric (the science of debate).
It has been given the Latin name argumentum ad verecundiam, and evidence from psychology has born out that it works. People are inclined to believe an authority figure, sometimes even over common sense.
Marketers know that one of the most persuasive ways to sell something is to get a testimonial. This is why speakers are introduced by someone else, for example. If another person gets up and lists the speaker’s accomplishments, it means a lot more to the listeners than if the speaker stands up, introduces herself, and lists off her own accomplishments.
This is the case even when the introducer knows nothing about the person except what he reads off of a card or teleprompter.
When the person who is providing the testimonial is perceived as an authority figure, it’s even more potent. This is why some books have quotes from authorities on them and why politicians seek celebrity endorsements. For example, some people voted for Barack Obama in 2008 because Oprah Winfrey, an authority figure if ever there was one, endorsed him publicly.
Ultimately, in science (as in the rest of life) people should use their own logic to evaluate the arguments put forward by the experts. Fortunately, scientists are trained to use their logic more intently than most of society.