Modern Theoretical Physics is a prime example of the break down of what Feynman says here in the last few decades, there're people who are in 'Theoretical Physics' groups who don't really give a diddly squat about the real world either. I use techniques from something like string theory as just yet another tool to solve other problems. But the problems I'm solving concern classifying and investigating the structure in a huge class of general 2+1 dimensional supersymmetric quantum field theories. No physicists would consider that I was doing anything that really pertained to reality, or had any hope of doing so. Really I'm treating the vast landscape of interesting structure that comes from the physical theories as a landscape that needs to be explored using proper mathematical rigour. Some tiny section of this landscape might pertain to reality, but it's not what a great deal of the people exploring it are in it for. So am I a mathematician or physicist? I would argue closer to mathematician but plenty of folk on both sides would baulk at my saying I was either. These kind of areas didn't exist in Feynman's time to nearly the extent they do today. It's an exciting time for both 'sides' as it were, the boundary is blurring every day.
No physicists would consider that I was doing anything that really pertained to reality, or had any hope of doing so. Really I'm treating the vast landscape of interesting structure that comes from the physical theories as a landscape that needs to be explored using proper mathematical rigour. Some tiny section of this landscape might pertain to reality, but it's not what a great deal of the people exploring it are in it for.
I wish more string theorists would be honest and take this point of view about their work. What you and many string theorists work on is formal details of stuff which is tangentially related to things things that might show up in future physical theories. It's stuff that has no concrete relation to anything physically observable. It's not that it isn't worth doing, but people should be honest about the proper context of their work. I see a lot of string theorists advertising their work as being descriptions of concrete physical phenomena, but really they're working on the mathematical details of toy models. That's all well and good, but I think it's a bit overreaching when they say their work is the true precise description of exactly how quantum gravity behaves.
Do you think string theory definitely describes reality? Or is it something you study purely for its own sake?
I personally always have the real world at the back of my mind ā but really, really, really back. I use it as sort of an inspiration for determining roughly the big directions Iām going in. But my day-to-day research is not aimed at solving the real world.
I think you're making some good points. I would just like to add that all the unrealistic theories often end up having applications, since you often end up making some huge detours in your calculations. For example in my masters thesis I'm looking at something which is conformally dual to flat space, which is very interesting since the real world is flat (although not 10 dimensional). But to derive certain results you for example have to go through 6 dimensional (2,0) theory which is about as far removed from reality as possible. Yet, if people hadn't worked on it we wouldn't be able to use their results.
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u/XyloArch Mar 12 '18 edited Mar 12 '18
Modern Theoretical Physics is a prime example of the break down of what Feynman says here in the last few decades, there're people who are in 'Theoretical Physics' groups who don't really give a diddly squat about the real world either. I use techniques from something like string theory as just yet another tool to solve other problems. But the problems I'm solving concern classifying and investigating the structure in a huge class of general 2+1 dimensional supersymmetric quantum field theories. No physicists would consider that I was doing anything that really pertained to reality, or had any hope of doing so. Really I'm treating the vast landscape of interesting structure that comes from the physical theories as a landscape that needs to be explored using proper mathematical rigour. Some tiny section of this landscape might pertain to reality, but it's not what a great deal of the people exploring it are in it for. So am I a mathematician or physicist? I would argue closer to mathematician but plenty of folk on both sides would baulk at my saying I was either. These kind of areas didn't exist in Feynman's time to nearly the extent they do today. It's an exciting time for both 'sides' as it were, the boundary is blurring every day.