Do we fall too easily for beautiful laws in physics?

1 Jun 2018

Dr Sabine Hossenfelder. Image: HossenfelderS/Wikimedia Commons (CC BY-SA 4.0)

Is beauty leading physics astray? Dr Sabine Hossenfelder has written a book on the subject and she was in Dublin this week to talk about it. Dr Claire O’Connell reports.

Is physics too in awe of beautiful laws? And could that attraction be blinding us to avenues towards a deeper understanding of how the universe works? That’s the intriguing premise of a new book to be released on 12 June called Lost in Math: How Beauty Leads Physics Astray by Dr Sabine Hossenfelder.

“It is about what theoretical physicists mean when they say a law is beautiful and how that influences their research,” explained the physicist, author and blogger, who was in Dublin City University (DCU) earlier this week to talk at the Irish Quantum Foundations 2018 conference.

Speaking at a public lecture during the event, Hossenfelder set out a stark backdrop for her argument: a ‘crisis’ in physics where basic frameworks for understanding the universe – such as Einstein’s theory of general relativity, and the standard model of particle physics – have not changed much of late.  

“General relativity is more than 100 years old, and the standard model was largely completed in 1970s,” she said. “The mathematical structure of these theories has remained unchanged.”

Dazzled by beauty

Of course, some slowdown is expected as a field matures, she noted, but could there be more to it?

“The argument that I am pushing in the book is that, I think the reason why we haven’t seen progress in the foundations of physics in the last 40 years is that physicists rely too much on their sense of beauty to pick theories,” Hossenfelder told

That beauty comes in the form of simplicity, elegance and naturalness, but those elements may not always combine to describe the reality of the universe. “I do think that mathematics is a form of art, with very strict rules, but in physics we are doing science and our task is to find useful descriptions of nature,” she said.

Beauty may even lead to a vicious cycle instead. “[Physicists] use the sense of beauty which they extract from experience or intuition and theories they know already and developed in the past, then they try to use this to construct new theories and hypotheses,” said Hossenfelder. “But experiments come up with a null result, and that is not very useful for finding the right theory. The point of the book is that we have to get over these ideas of beauty.” 

One of the key steps to liberation from this sense of beauty is to wake up to it, she explained. “I think the first thing is that theoretical physicists must become aware of what they are doing.

“Of course, who would go looking for an ‘ugly theory’ but, if we find a new law of nature that works, we will come to find it beautiful … It will be a type of beauty that is not like the previous types or it may be, you never know.”

Quantum conundrums

Hossenfelder’s own studies at the Frankfurt Institute for Advanced Studies focus on quantum gravity, which tries to understand the nature of spacetime. “It’s complicated because the maths is complicated, but we are trying to find out what space and time are, because there are some things that we don’t understand,” she said. 

The standard model of particle physics is pretty good for describing the particles that move in spacetime and they have a gravitational pull, explained Hossenfelder, but these are quantum particles and the theory that describes gravitational pull (general relativity) is not a quantum theory. When we try to put these two theories together, it doesn’t work.”

Maths, physics and philosophy in the mix

After she left school, Hossenfelder studied both maths and physics. She eventually chose to move forward with physics, but she retains a leg in the maths camp.

“I’m interested in the fundamental mathematical structure of everything, and [asking] are there limits to what you can do with mathematics,” she said. “I also have a tendency to drift into philosophy.”

Dr Sabine Hossenfelder. Image: HossenfelderS/Wikimedia Commons (CC BY-SA 4.0)

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Dr Claire O’Connell is a scientist-turned-writer with a PhD in cell biology and a master’s in science communication