You are ktizo both have the same misconception. Perhaps this explains your belief in the value of models.
Those formulas are not models! They are exact mathematical representations of a phenomena!
A model by it's nature can not include everything, they include everything possible of course, but the world is too complex for them to include everything, so they must estimate. If you have a feedback loop with the real world you can tune your model to make it useful, but you can never get out of it anything you did not put in, since it's impossible to include everything.
If a model did include everything then of course it would work perfectly. But it's not possible to do that in the real world.
Those formulas are models. They describe the world and can predict it's behaviour, but can also break down under certain conditions. For example, what happens when I put 240V across a regular 20Ohm resistor? According to V=IR you get 12A running through it - but I doubt you'll get that for very long.
By your argument, V=IR must then be a "model" and is useless, with no predictive power, etc, etc. In practice, the only difference between those formulae and a more complex model is one of degree.
No, those formulas are exact, you are just using them incorrectly.
You think V=IR describes a resistor, it does not. It describes electricity. So it's not surprising that when applied to a resistor it doesn't work. You are trying to model a resistor, but you are not including everything in your model, so it fails.
Which is exactly what I'm warning about.
> By your argument, V=IR must then be a "model" and is useless, with no predictive power
V=IR is not a model. Using it to describe a physical resistor is a model.
Suppose I never touched a real resistor in my life, and the only information I had was an understanding based on some other law that V=IR. Now I want to use that information to predict what a resistor will do. I will fail - among other things it doesn't take into account inductance or capacitance.
Which is why it is very very important to know what your equation describes. You thought that V=IR completely describes a physical resistor, when it does not.
Now you know why it's incredibly dangerous to try to learn anything from a model. If even something as simple as Ohm's law can be confusing, imagine how many error a model with hundreds of equations has.
>You thought that V=IR completely describes a physical resistor, when it does not.
V=IR is a mathematical model of a resistor, useful under most circumstances except pathological ones. Can the model be improved? In most cases yes, but then it loses some value due to complexity.
This is why there are scientists in Antarctica: they're testing the model, gathering new data to see how well the models hold up. But for some reason you're acting as if those poor scientists haven't realised this yet.
If you want to continue to argue the point feel free, but you're disagreeing with every scientist and engineer on the planet. Try looking at http://en.wikipedia.org/wiki/Mathematical_model - what do you see? Ooh - equations.
"essentially, all models are wrong, but some are useful" -- George E. P. Box
It's the basis for a model of a resistor, but it's an exact equation of resistance. There is a difference.
> they're testing the model, gathering new data to see how well the models hold up.
No, they are not testing the model, they are trying to improve the model by recording what it did in the past.
To test the model you make a prediction of what it will do in the future, then wait and see if it happens the way your model shows. It can't be done for climate though since it would take decades. They do try to test it by giving it old data and seeing if it predicts current conditions - which is great, but does not help in predicting the future since the input will be different this time.
> you're acting as if those poor scientists haven't realised this yet.
They most definitely do realize how poor the results are (just see how many weasel words they put in the paper linked to this topic), they just have no better options.
Do you really not understand the difference between a model and a fundamental equation? A model does not have perfect input, and a model may not include all things that can affect the output.
An physical law (an equation usually), is exact. It might not apply to real physical objects (like the ideal gas law), but that doesn't make the equation a model - the equation is correct for where it's used, it just doesn't cover everything.
Excellent quote BTW, but don't take from that that everything is a model. The real world is not a model - if I test something and it does something in the real world, I have real information. In a model I only have the information I put in it, and it's simply impossible for me to put in everything.
They made a model - but they missed something. Good thing they were able to test it, and see what they missed. But if you don't have the ability to test? (Like climate.) Then your model is useless.
A model is useful only if you can test it. The model will help you know what to test, the model will help you see if you understand the topic. But a model you can not test is useless.
(Just to repeat myself: I'm not arguing about models, I'm arguing about models that can't be tested.)
The glacier model is wrong, but wrong in the wrong direction (Actually I think that's combined results from multiple models, but anyway...). How do they know? Because there are climatologists out on the ice, or in satellites taking measurements-1. Testing the model - you know, all that stuff that is supposedly impossible to do.
1- there are even high resolution GPS modules in Greenland which can estimate ice loss by how far up the crust lifts (as well as detecting plate tectonics).
Those formulas are not models! They are exact mathematical representations of a phenomena!
A model by it's nature can not include everything, they include everything possible of course, but the world is too complex for them to include everything, so they must estimate. If you have a feedback loop with the real world you can tune your model to make it useful, but you can never get out of it anything you did not put in, since it's impossible to include everything.
If a model did include everything then of course it would work perfectly. But it's not possible to do that in the real world.