Leonard Susskind - Why Do We Search for Symmetry?

Symmetry is when things are the same around an axis. Turn it and it looks the same. A simple idea with profound implications for understanding the universe and for predicting how it works. Finding symmetries, and discerning when they break, is one key for understanding fundamental physics.

Leonard Susskind is the Felix Bloch Professor of Theoretical Physics at Stanford University, and Director of the Stanford Institute for Theoretical Physics. He received a BS in physics from City College of New York and a PhD from Cornell University.

Closer to Truth presents the world’s greatest thinkers exploring humanity’s deepest questions. Discover fundamental issues of existence. Engage new and diverse ways of thinking. Appreciate intense debates. Share your own opinions. Seek your own answers.

[CloserToTruthTV]

Do you agree with Susskind's assessment of beauty and symmetry? Leave a comment below with your thoughts!

[michaelanderson]

"Not in the circles I move in"
What a diplomatic way to exclude the crackpots 😁

[lunalaufmann]

correct: SU(3) symmetry of quarks is generating a messed-up model. But before rejecting symmetry I would reject quarks...

[ddacaro]

Beauty is not objective. Beauty emerges inside brains and is therefore only knowable as an experience, subjective, personal, and empirical. However, it's not entirely volitional as Susskind suggests. At least not in the case of experiencing beauty in response to certain opportunities for which we've evolved predilections for fitness, like mates (some aspects of attraction including but not limited to bilaterally symmetrical features). In several cases at least, beauty response is not in the eye of the beholder.

[stevenverrall]

Wow, LS could not be more wrong about natural symmetries! Just because he has failed to find the underlying symmetries of nature does not mean they don't exist!

[douglasauruss]

That grin after asking the symmetries question at 5:41

[neitherpeternorpaul]

What he says around 2:40 is simply not true. Just because natures symmetry is "approximate" doesn't mean it's accidental. I'm not in the position to give very good examples, but it's obvious that there are many body parts, or parts of plants that are 'approximately' symmetrical and one advantage of that is, that they can be replicated more easily. What I mean by that is, that developing symmetrical body parts is less complex than developing (and inheriting the genetical information) the same pair of body parts without any symmetry. It simply reduces the amount of 'information' needed to develop the same amount of body parts. 'Information' has to be seen as shorthand and Paul Janich has written a wonderful small book on the reasons for why the term 'information' is misleading. And the universe does care what we think insofar, as we influence the reproduction of certain species on the basis of our perception (domestication and sexual selection). Another example would be the shape of some flowers that are based on the preferences of bees because they look a bit like bodyparts of bees and are thereby attracting them. This again could be seen as some type of 'symmetry' even if it's only approximate. There is another book called "The Secret Life of Trees" by Colin Tudge, and the introductory chapter is a really curious one for anyone interested in philosophy because he makes the connection to philosophical thoughts about order in nature very explicit.

[samsam]

If you only look for beauty and symmetry, you'll probably miss a lot of ugly facts.

[bananacabbage]

I agree with Susskind that beauty is a side show. The real reason we use gauge symmetry is because it leads to consistent field theories that agree with nature. However he is wrong that symmetry is approximate and accidental. There is no justification for that claim. Susskind's famous holographic principle is a consequence of hidden symmetry but he fails to see it because of his blinkered view. There is still reason to think that there is a lot more symmetry in nature, regardless of beauty. In QCD, flavour symmetry is approximate but SU(3) colour symmetry is not. Susskind's selective choice on which symmetries to look at is not objective. Gauge symmetries are real. Just stating that everyone in his circle thinks otherwise is not justification. This is combined with the mistaken belief that energy conservation in general relativity is approximate. Symmetry is important in physics and this negative attitude towards it explains why theorists have ceased to make progress with understanding the underlying fundamentals of string theory and everything else.

[raimundohenriques]

Symmetry and beauty is a human construct and as this exist only in human mind. Then I can “view ” the world as beauty or not

[johnunvaxxed]

Leonard is downplaying the importance of symmetry and simplicity here

[Dyslexic-Artist-Theory-on-Time]

I disagree, we come out of beauty, is a sphere more beautiful if we are looking at it?

[jimsteen]

LS is my favorite physicist. Brilliant. Humble.

[omkarrajebhosale]

Love the way he presented his thoughts and the point where he says that Nature is what it is, regardless of whether we think it is beautiful or not!

[Warguard]

These talks are refreshing and thought engaging, I agree with Susskind " the Universe" doesn't give a damn what we think or whether we are right or wrong!

[empemitheos]

Nature's tendency to approximately approach perfect mathematical structures can still tell us a lot about what is going on underneath the apparent chaos

[woongda]

It is beautiful because you can see God in it. (or behind it)

[johnrowson]

The symmetry is the quality that allows math to differ with observation?

[bpclowery]

I admire scientists like Leonard Susskind, however, I have so many issues with their thought processes. For example, Professor Susskind states at 3:01. "The Universe doesn't give a damn what we call beautiful'. The fact that we are even alive as a species and can look at the Cosmos is beautiful. The face that human life evolved over billions of years to what it is today is beautiful. It is testimony of what is possible in this Universe; human intelligence that can discern itself. His statement that symmetries are only approximate and therefore, accidental in nature just does not ring true with me. The Anthropic Principle states that things are the way they are because this is one of the successful Universes to live in. In non-successful Universes, we are not around to ask questions about the Universe because we cannot exist in them. So to me, nothing is accidental. If we are alive and can question our existence in the Universe that we live, then it has a purpose.and we therefore have a purpose. To exist in a successful Universe, too many accidents have to happen for us to be here, way too many.

[AFRoSHEENTARCMICHAEL]

Well music is symmetrical and 12TET isn't perfect except for the Octave. Why is it humans seemed programed, whether musically trained or not, to be able to tell the difference between a good singer and a bad singer? A bad note meaning one not in the scale? Even human beings are symmetrical. Your right side mirrors your left side? Honestly I think you know but lie.