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Episode Twelve – Quora Questions on Physics

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Today we answer some Quora questions about physics. We cover string theory, particle-wave duality, thought experiments and more!

Click here to download the PDF transcript. The PDF version does not have illustrations, but might be easier to read on certain devices, such as your eReader.

Episode Transcript

[Please note that this may not exactly match the audio. However, there should be no significant differences.]

Introduction

Hi everyone! This is episode twelve of the Metaphysics of Physics podcast.

With this show, we are fighting for a more rational world, mostly by looking through the lens of the philosophy of science. We raise awareness of issues within the philosophy of science and present alternative and rational approaches.

You can find all the episodes, transcripts and subscription options on the website at metaphysicsofphysics.com.

I am Ashna, your host and guide through the hallowed halls of the philosophy of science. Thanks for tuning in!

Today we are going to answer some Quora questions relating to physics.

What are the signs that must exist in the universe so that we consider the string theory correct?

It is widely believed that one of the main problems with string theory is that nobody has a good idea of which practically observable facts would verify string theory. Or, to put it another way: We really have little idea of any practical way to test it.

string theory

Kind of hard to test a theory that talks about stuff like this …

There are of course people who believe that there are ways it can be verified. But, the problem is that they are not what we could currently call practical.

It is generally thought that we would need particle accelerators far more energetic than anything we know how to build with existing technology. It simply requires far too much energy.

In fact, so much energy that it is conceivable that no amount of technological advancement will ever make it practical.

There are a couple of indirect methods through gravity waves and the like that people think might be able to verify string theory. However, I think all of this rather misses the point. Let me explain.

Let us suppose that now or in a hundred years, someone comes up with an experiment that seems to suggest string theory is true. What would this imply?

Would it imply that all of the mathematics of string theory is true? Let us suppose this is the case.

Does this prove that reality has nine, ten, eleven or whatever number of dimensions? No. Because the entire concept of dimensions is an abstraction and no amount of evidence will validate “the universe having X dimensions”.

Dimensions are a mathematical concept. They have no physical existence and you cannot explain anything by saying “space” or “reality” has ten dimensions.

Dimensions graph

Dimensions are a mathematical concept. The higher dimensions are not shown here, but the concept is similar

When we say that “space” has three dimensions, we simply mean that we can identify three abstract spatial relationships, height, length, depth or whatever terms you want to use for those three spatial relationships.

But, those relationships are purely mathematical, they are not physical. Space itself has no dimensions, we simply identify mathematical relationships to describe spatial relationships.

So, even if tomorrow I showed that all of the math of string theory works, you still have an issue. What does the math really mean? Does it mean that space has all those dimensions?

If not, what does it mean?

You see, you have to be aware that your theory requires a rational interpretation of observable reality. You cannot simply come up with a series of equations, show the math works and then interpret that math however you want. That is a huge failing of modern physics and why so much of it makes little or no sense.

You have to provide a rational interpretation of the math that is concordant with a rational metaphysics and which describes how reality actually works. Not how you think it works.

Which is the real issue here: What do you think string theory implies? Because many of the things that people think it implies cannot be proven to be true, as they violate rational metaphysics.

Hence, in a sense, much of string theory can never be proven to be true. If you hope to be able to prove any of it to be true, then you have to make sure it is rational as well.

As it stands right now, I see very little chance of that happening…

4 comments

  1. Could you please explain how Quantum time is indeterministic based on the observation:
    Entropy and the Nature of Time with Edwin C. May 5:55

    1. Sorry for taking a while to get back to you, we have been very busy!

      We are going to briefly cover time in episode sixteen of the podcast, where we talk about space and time. This will be out around the 25th of March.

      But, I can somewhat address your question now:

      We do not really think very much about “quantum time”. As far as we are concerned, time is simply a relational concept.

      What do we mean by that? We mean that time is a concept, it is a measurement of change. It is not a dimension or part of the universe. It simply measures change in things.

      We do not agree that Einstein or anyone else has shown that time is a dimension or that is part of the universe or that time is affected by speed. If it is a concept, how could it be, that makes no sense?

      Your video talks about the Arrow of Time. Well, if that concept is to have any validity, surely it refers to causality. Things happen the way they do because things have to act according to their nature.

      Broken glasses do not leap up and reassemble themselves. Gases do not become more orderly and bunch into a small area. Why? Because in both cases it would violate the nature of the broken cup or the gas to act in such a way. But, not because of some mysterious “Arrow of Time” which somehow dictates how they must act.

      Things do not generally happen in the reverse order that we observe, because of the nature of the entities. Unless of course, it is in the nature of the entities to act that way in a given context.

      We do not have to resort to entropy or “Arrows of Time” to explain this kind of thing. Or indeed anything to do with time at all. We just have to know which actions are consistent with the nature of the entities involved.

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