# Hawking's Model-Dependent Realism

• Mr Davis 97
In summary: Yes, Newton was wrong about a lot of things, but that doesn't mean that his theory of gravity is wrong.

#### Mr Davis 97

This is a soft question, but I am reading Hawking's "The Grand Design" and he mentions that "Although it is not uncommon for people to say that Copernicus proved Ptolemy wrong, that is not true ... One can use either picture as a model of the universe." He goes on to say that we hold the heliocentric model to be true because it is the simpler of the two.

This is my question: How is the heliocentric model not "actually" more correct the geocentric model? With modern technology (as well as with the theory of gravitation) isn't it clear that the heliocentric model is objectively true? Could someone play devil's advocate and somehow fudge together a consistent description of the universe in today's world that uses Ptolemy's geocentric model?

I guess what he meant was that the choice of the "main" point is arbitrary. Math necessary to describe the kinematics of the Solar system is much easier if you put its center where the mass center is, but in general you can use any other point for that.

Actually sometimes you have no choice but to use an "inconvenient" point as the center. Simulating Jupiter moons is much easier when you assume they revolve around Jupiter, but it becomes problematic when you want to deal with whole Solar system at once.

Borek said:
I guess what he meant was that the choice of the "main" point is arbitrary. Math necessary to describe the kinematics of the Solar system is much easier if you put its center where the mass center is, but in general you can use any other point for that.

Actually sometimes you have no choice but to use an "inconvenient" point as the center. Simulating Jupiter moons is much easier when you assume they revolve around Jupiter, but it becomes problematic when you want to deal with whole Solar system at once.
But is he not saying that one is completely equivalent to the other from a "realness" point of view (not considering mathematical complexity)? I don't understand how that could be so, if clearly the Earth revolves around the sun because of gravitation. Doesn't this mean that the heliocentric model is "more true" than the geocentric model in a real sense?

Mr Davis 97 said:
clearly the Earth revolves around the sun

It doesn't. It revolves around the mass center of the system.

"More true", "real sense"" in such contexts are very poorly defined. You may think they are, but when you try to analyze them you will soon learn what you though was intuitively obvious evades precise understanding.

Let's get back to the Jupiter example. Imagine living on the Ganymede. Which system - the one centered on Ganymede, the one centered on Jupiter, the one centered on Sun - is the "real one"? But this hierarchy of center points doesn't end here, what about the center of our Galaxy? Center of the local group of galaxies?

Or perhaps - once you realize the choice is arbitrary - choice of the center point doesn't actually matter?

Mr Davis 97 said:
This is my question: How is the heliocentric model not "actually" more correct the geocentric model?
The 'truth' of the models are always matter of measurement accuracy. At the accuracy available by the 'modern technology' it is 'evident' that the heliocentric model is the better, but for 'not modern technology' it is actually quite taxing to find the problems with the geocentric model, and at that level there are no advantages in using the heliocentric one.

According to that, the geocentric model is not 'wrong'. It is just ... well, out of its relevance range if somebody brings it up now.

It might be better to check it out on a less absurd example. Is Newton 'wrong'? We already has better models and math available...

Tosh5457

## 1. What is Hawking's Model-Dependent Realism?

Hawking's Model-Dependent Realism is a theory proposed by physicist Stephen Hawking that suggests we can only understand the universe through the lens of our models and theories about it. This means that there is no one "correct" description of reality, but rather our understanding of reality is limited to the models and theories we create.

## 2. How does Hawking's Model-Dependent Realism differ from traditional scientific realism?

Traditional scientific realism holds that there is one objective reality that exists independently of our observations and models. However, Hawking's Model-Dependent Realism challenges this notion by suggesting that our understanding of reality is limited by our models and theories, and that there may be multiple equally valid ways to describe the universe.

## 3. What evidence supports Hawking's Model-Dependent Realism?

Hawking's Model-Dependent Realism is supported by the fact that different theories and models have been used throughout history to describe the same phenomena. For example, Newton's laws of motion were later replaced by Einstein's theory of relativity. This shows that our understanding of reality is constantly evolving and subject to change based on the models we use.

## 4. Is Hawking's Model-Dependent Realism widely accepted in the scientific community?

Hawking's Model-Dependent Realism is a controversial theory and is not universally accepted in the scientific community. While some scientists support the idea that our understanding of reality is limited by our models, others argue that there is a single, objective reality that we can strive to understand.

## 5. How does Hawking's Model-Dependent Realism impact our understanding of the universe?

Hawking's Model-Dependent Realism challenges us to question our assumptions about reality and to approach scientific theories and models with a critical eye. It also highlights the importance of constantly revising and updating our understanding of the universe as new evidence and models emerge.