There can only ever be one reality, and so there can only ever be one correct theory of reality.
I disagree with this. A theory is basically a model (or pertains to one). Models by necessity leave out details of the thing they’re modelling (if you disagree, then the best model of reality is simply reality, and we already have that). So depending on which features of reality you think are relevant, you can have multiple models of reality bringing out each of those features. The theories based on those models will sometimes make different predictions, but if they’re good models they’ll agree most of the time, and you make predictions using the model that makes those sorts of predictions correctly most of the time.
As an illustration, look at maps of the surface of the Earth. There are multiple projections based on preserving different relevant information. If you want to plan a sea journey, you use one; if you want to plan a land journey, you use a different one. A globe represents both more accurately, but is harder to carry around / print out of a computer.
Surely our models of physics can have the same sorts of properties; what allows you to make predictions about gravity may not be the same model that allows you to make predictions about electromagnetism.
I have to disagree with tommccabe—the fact is that model and theory are as different as technical manual and source code. There is only one perfect theory of reality—the theory that is reality—but innumerable models for different domains and purposes. Yes, many of our models began as theories, but that is because a good theory is by necessity a good model.
You have a peculiar use of words reality and theory. I feel that theory and model are more or less the same—our ways to describe the reality. The word model is used when the description is not elegant and visibly incomplete. As for the analogy, you can have multiple source codes that do the same work. How do you establish which is the only perfect one, having access to the user interface only?
You have a peculiar use of the word model—up my alley, that word is used when you are analyzing a particular problem, however few approximations you make.
There can be many different parametrizations of the same surface, but they will each have the same topological and geometric properties.
So we could have several correct models—i.e. parametrizations which have the correct characteristics—and a single theory—i.e. set of characteristics with which to choose parametrizations. But each model will predict different yet-undiscovered characteristics. Using these new characteristics to make predictions would constitute different theories which are consistent-as-of-yet. Given the current state of quantum physics, different theories seem to be able to remain consistent for a while.
My use of model and theory have been prescriptive based on my interpretations of the thread below. I didn’t intend this but all of the confusion and disagreement seems to have been in our minds.
There is only one perfect theory of reality—the theory that is reality … a good theory is by necessity a good model.
This doesn’t seem right. A good model necessarily leaves things out; if you didn’t need to leave out some details, then you’d use the object itself, not a model of it. But if a good theory is necessarily a good model, then a good theory also necessarily leaves something out. But then the theory can’t be reality, since reality can’t leave any of itself out of itself.
This doesn’t seem right. A good model necessarily leaves things out; if you didn’t need to leave out some details, then you’d use the object itself, not a model of it.
Unless it was more expensive to build the object than to build the model. Or if the design process required information in the model that is not obvious in the object.
But the true answer is “I meant ‘good’ in the sense of accurate to reality, not in the sense of ‘computationally tractable’.”
I did—I disagreed with your response to thomblake, but what I wanted to say was to thomblake, so I replied to him. If we were in a room, I would be facing him* and gesturing at you only to indicate that I was not supporting your argument.
I apologize for not being clear.
Edit: And further for not reading—you said model. I do not disagree, it appears.
It took me a while to figure out how to answer this. Probably, “I don’t care and won’t object to you using that particular pronoun, and I generally don’t see how my gender is anybody else’s business.”
“So depending on which features of reality you think are relevant, you can have multiple models of reality bringing out each of those features.”
Of course, but then, these theories don’t compete with each other. Everyone simply believes in both. I believe in both the atomic model of chemistry and the quantum model of electrons, and both can be used to describe the behavior of, say, a sugar molecule (but on different levels).
I disagree with this. A theory is basically a model (or pertains to one). Models by necessity leave out details of the thing they’re modelling (if you disagree, then the best model of reality is simply reality, and we already have that). So depending on which features of reality you think are relevant, you can have multiple models of reality bringing out each of those features. The theories based on those models will sometimes make different predictions, but if they’re good models they’ll agree most of the time, and you make predictions using the model that makes those sorts of predictions correctly most of the time.
As an illustration, look at maps of the surface of the Earth. There are multiple projections based on preserving different relevant information. If you want to plan a sea journey, you use one; if you want to plan a land journey, you use a different one. A globe represents both more accurately, but is harder to carry around / print out of a computer.
Surely our models of physics can have the same sorts of properties; what allows you to make predictions about gravity may not be the same model that allows you to make predictions about electromagnetism.
I would say the same in simpler words:
We only have one territory but we can have an infinitude of maps each serving different purposes.
I have to disagree with tommccabe—the fact is that model and theory are as different as technical manual and source code. There is only one perfect theory of reality—the theory that is reality—but innumerable models for different domains and purposes. Yes, many of our models began as theories, but that is because a good theory is by necessity a good model.
You have a peculiar use of words reality and theory. I feel that theory and model are more or less the same—our ways to describe the reality. The word model is used when the description is not elegant and visibly incomplete. As for the analogy, you can have multiple source codes that do the same work. How do you establish which is the only perfect one, having access to the user interface only?
You have a peculiar use of the word model—up my alley, that word is used when you are analyzing a particular problem, however few approximations you make.
Well, maybe I am too much influenced by the Standard model of elementary particles. There are no important reasons why not call it a theory, IMO.
None of these terms have rigid definitions, it seems.
There can be many different parametrizations of the same surface, but they will each have the same topological and geometric properties.
So we could have several correct models—i.e. parametrizations which have the correct characteristics—and a single theory—i.e. set of characteristics with which to choose parametrizations. But each model will predict different yet-undiscovered characteristics. Using these new characteristics to make predictions would constitute different theories which are consistent-as-of-yet. Given the current state of quantum physics, different theories seem to be able to remain consistent for a while.
My use of model and theory have been prescriptive based on my interpretations of the thread below. I didn’t intend this but all of the confusion and disagreement seems to have been in our minds.
We certainly seem to be arguing about words—you’re probably right that the confusion is just in our minds.
This doesn’t seem right. A good model necessarily leaves things out; if you didn’t need to leave out some details, then you’d use the object itself, not a model of it. But if a good theory is necessarily a good model, then a good theory also necessarily leaves something out. But then the theory can’t be reality, since reality can’t leave any of itself out of itself.
Unless it was more expensive to build the object than to build the model. Or if the design process required information in the model that is not obvious in the object.
But the true answer is “I meant ‘good’ in the sense of accurate to reality, not in the sense of ‘computationally tractable’.”
(Er, you might want to check the author, I did not write the above post.)
I did—I disagreed with your response to thomblake, but what I wanted to say was to thomblake, so I replied to him. If we were in a room, I would be facing him* and gesturing at you only to indicate that I was not supporting your argument.
I apologize for not being clear.
Edit: And further for not reading—you said model. I do not disagree, it appears.
* “Him”, right? “Thom” sounds like a masculine.
Sure why not
Wait—is that “whatever pronoun you like, I don’t mind” or “that’s not the right deduction, but I am a man, so whatever”?
It took me a while to figure out how to answer this. Probably, “I don’t care and won’t object to you using that particular pronoun, and I generally don’t see how my gender is anybody else’s business.”
Thank you for telling me.
Or does that mean thomblake is Clippy?
Wait, don’t you also have a “I don’t care what pronoun you use for me” thing too?
“So depending on which features of reality you think are relevant, you can have multiple models of reality bringing out each of those features.”
Of course, but then, these theories don’t compete with each other. Everyone simply believes in both. I believe in both the atomic model of chemistry and the quantum model of electrons, and both can be used to describe the behavior of, say, a sugar molecule (but on different levels).