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You do the same thing in physics when your calculations assume no friction or wind resistance. It's not because friction or wind resistance aren't commonly pre

You do the same thing in physics when your calculations assume no friction or wind resistance. It's not because friction or wind resistance aren't commonly present in real life. Of course they are. It's because they're tougher to calculate and often require estimation. You'd be missing the point if you assumed these calculations are meaningless because you're not including those factors. They're just ways the answer could change in real life applications that need to be kept in mind. And just like they don't footnote every physics example with "[1] In the real world, friction and wind resistance exist and will affect the end result," they don't do it in economics, either. This is kind of an understanding of the basics of the concepts.

falsedan 9y ago
> You'd be missing the point if you assumed these calculations are meaningless because you're not including those factors. We don't think they're meaningless, just that the calculated results won't 100% predict the actual movement of physical bodies in the real world. Friction and wind resistance are well-understood, and a reasonable model can have its predictions altered to suit the local conditions. The perfectly competitive market doesn't have these well-understood complications. If you have a prediction of a block sliding down a ramp, you could easily give a range for expected error due to the effects of friction and wind resistance (using known, measured values taken of commonly-seen materials & conditions). You could even take the modelled prediction, go out in the field, plug in the local conditions, and get an accurate result!
- moduspol 9y ago
  > We don't think they're meaningless, just that the calculated results won't 100% predict the actual movement of physical bodies in the real world. Right, and the same applies with economics. I'm not claiming human behavior (relative to economics) is comparable scientifically to friction--just that it's a compounding factor that doesn't keep us from meaningfully studying the subject.
  - falsedan 9y ago
    > the same applies with economics My second paragraph tries to make the case that, with economics, the real-world conditions which are ignored in order to simplify the calculations are not nearly as well understood, nor measurable, or adjustable for as friction and air resistance. Plus, they do not have as linear a response as friction/air resistance. > it's a compounding factor that doesn't keep us from meaningfully studying the subject I disagree, it makes the study of the perfect market completely unusable for predicting real-world behaviour.
    - moduspol 9y ago
      > My second paragraph [...] Indeed--and it does a good job. The question is whether there is usefulness in the science despite this. > I disagree, it makes the study of the perfect market completely unusable for predicting real-world behaviour. Indeed, just like nobody uses frictionless calculations for predicting real-world behavior. We can simultaneously acknowledge unknowns in a science without discounting it entirely.
      - falsedan 9y ago
        You’re ignoring the pasts of my argument which disagree with your position. I argued that, since the effects of the ignored complications in physics are easy to measure and account for in a specific situation, the ideal models are still useful. And that this isn’t the case with the economic models, since measuring friction is vastly simpler than measuring the irrationality of consumers in a given market. To boil it down: the unknowns (which are ignored to simplify calculations) in physic models and known; in economic models they are unknown. And, to put it another way: given a mass with momentum m which you want the change to m’, a simple physics model will tell you what acceleration to apply & would get you pretty close once you accounted for friction. Given an inflation rate and a target, no simple economic model would predict what policies to set with more accuracy than guessing. These economic models are useless for predicting real-world outcomes; they are pedagogic tools only.
        9y ago
mypalmike 9y ago
The difference is that you don't end up with physics ideologues claiming all real objects are frictionless.
- moduspol 9y ago
  Nobody claims this. This whole thread is an example of the opposite, though, where people are claiming that without "friction" being explicit in every calculation, studying "physics" is not valuable.

falsedan 9y ago

> You'd be missing the point if you assumed these calculations are meaningless because you're not including those factors. We don't think they're meaningless, just that the calculated results won't 100% predict the actual movement of physical bodies in the real world. Friction and wind resistance are well-understood, and a reasonable model can have its predictions altered to suit the local conditions. The perfectly competitive market doesn't have these well-understood complications. If you have a prediction of a block sliding down a ramp, you could easily give a range for expected error due to the effects of friction and wind resistance (using known, measured values taken of commonly-seen materials & conditions). You could even take the modelled prediction, go out in the field, plug in the local conditions, and get an accurate result!

moduspol 9y ago
> We don't think they're meaningless, just that the calculated results won't 100% predict the actual movement of physical bodies in the real world. Right, and the same applies with economics. I'm not claiming human behavior (relative to economics) is comparable scientifically to friction--just that it's a compounding factor that doesn't keep us from meaningfully studying the subject.
- falsedan 9y ago
  > the same applies with economics My second paragraph tries to make the case that, with economics, the real-world conditions which are ignored in order to simplify the calculations are not nearly as well understood, nor measurable, or adjustable for as friction and air resistance. Plus, they do not have as linear a response as friction/air resistance. > it's a compounding factor that doesn't keep us from meaningfully studying the subject I disagree, it makes the study of the perfect market completely unusable for predicting real-world behaviour.
  - moduspol 9y ago
    > My second paragraph [...] Indeed--and it does a good job. The question is whether there is usefulness in the science despite this. > I disagree, it makes the study of the perfect market completely unusable for predicting real-world behaviour. Indeed, just like nobody uses frictionless calculations for predicting real-world behavior. We can simultaneously acknowledge unknowns in a science without discounting it entirely.
    - falsedan 9y ago
      You’re ignoring the pasts of my argument which disagree with your position. I argued that, since the effects of the ignored complications in physics are easy to measure and account for in a specific situation, the ideal models are still useful. And that this isn’t the case with the economic models, since measuring friction is vastly simpler than measuring the irrationality of consumers in a given market. To boil it down: the unknowns (which are ignored to simplify calculations) in physic models and known; in economic models they are unknown. And, to put it another way: given a mass with momentum m which you want the change to m’, a simple physics model will tell you what acceleration to apply & would get you pretty close once you accounted for friction. Given an inflation rate and a target, no simple economic model would predict what policies to set with more accuracy than guessing. These economic models are useless for predicting real-world outcomes; they are pedagogic tools only.
      - 9y ago

mypalmike 9y ago

The difference is that you don't end up with physics ideologues claiming all real objects are frictionless.

moduspol 9y ago
Nobody claims this. This whole thread is an example of the opposite, though, where people are claiming that without "friction" being explicit in every calculation, studying "physics" is not valuable.