I love how physicists can take a complicated problem, and, using a simple analogy, make it much worse.

Comments here are hilarious! Understanding that labels given to a function are arbitrary was just the 1st step into understanding Gauge Symmetry. He is basically saying you need to grasp this concept in order to get into gauge symmetry. The fact that people think thats all that gauge symmetry is and now think they can explain it better than the physicist is HILARIOUS!!!

Let the guy off people, it is hard enough to explain gauge symmetry to an undergraduate in their final year, let alone anybody with no physics background.

My cat's breath smells like cat food.

Everyone knows a battery has a positive (+) and a negative (-) terminal. Gauge symmetry is the statement that the potential of each terminal is not physical, only the potential difference is physical. That is, we can arbitrarily assign a voltage to the battery terminals, as long as the potential difference is the same. A battery with 9v and 0v on the positive and negative terminals is physically equivalent to a battery with 4.5 on the positive and -4.5 on the negative. The difference in both cases is the same, 9V. So when we go to the store we simply ask for a 9V battery, without mentioning the potential of either terminal. The potential difference is what determines the electric field and the movement of charges across an electrical wire. There are many reasons why in physics we work with potentials and not potential differences. One reason is that it is a mathematical trick to solve differential equations (e.g. Maxwell equations).

This is lecture 1 in our series "Lawrence Krauss explains advanced physics concepts that Joe does not have the background to possibly understand."

I find Mr Krauss explanation more understandable than Eric Weinstiens

love when joe has scientists on the show

These comments are the Dunning-Kruger effect at its best.

Repeated himself for 15 minutes what he successfully explained within 4 mins

I admire Krauss for attempting to explain gauge symmetry, and, for me, I got something from it. Thank you for putting this on-line.

This is why I love Joe's podcast. So wide-reaching and random. I can tune in to listen to why Connor got his ass beat one day and the next, find out about gauge symmetry and how it applies to our lives. Such an accomplished guy and well deserving of the status he's achieved. Don't know him.. Will probably never meet him but proud and enamoured of his achievements and intellect. Thanks buddy.

The best analogy I know to explain this concept is as follows:

In military electronics schools, it is taught that current flows from negative to positive. In the civilian schools, it is taught that current flows from positive to negative. It doesn't matter which way you think current is flowing, it all works the same. That's the symmetry of electronics.

everyone says he's shit at explaining but he explained it clearly enough..

I just drove into a perfectly symmetrical tree.

I always take Gauge symmetry as a mathematical way to explain that there is something much more fundamental about the universe that we do not understand. Things such as spacetime (gravity) and electromagnetism may be emergent from something deeper but simpler. Our concept of fields is a sign that we are groping an elephant in a dark room. We use them to model the elephant with math but only see a small part of the whole, making for a convoluted idea of what we are actually exploring. That may be why our ideas are so complex and confused. Of course the argument is that our human condition may stand in our way of understanding, that nature does not have to make sense to us and math is the language to unlocking truths about our universe. That begs the question as to whether math is anything more than a human construct modeling what we experience....almost a quasi-religious state if you think about it....Lol, I know I thought math homework was child abuse when I was 12 years old.....

Concepts he touched on: Lagrangians, Hamiltonians, calculus of variations, spacetime manifolds, particle physics, Maxwell's equations, equivalence, special and general relativity, symmetry, conservation, closed systems, Lorentz transformations,... Pretty much all of physics. Even chaotic systems at the end. He switched from how to why to how again. And did it a thousand times better than I would have. At some point I would have just said, "It helps us with the math and gives us a deeper understanding of all of physics."

Lawrence is usually good at explaining things, but here he is paddling around in deep water.

What he’s describing is reification. He’s really struggling to overcomplicate a very simple premise. A rose by any other name would smell as sweet. I see a lot of public science advocates struggle to overcomplicate things like this.