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Shady i know its shocking, but for once your right :biggrin:. As i have said numerous times on this thread (???:biggrin:???), solving mathematical equations all semester is not gonna do anything to your economic intuition. If you wanna do maths, do maths, and i mean proper maths, not all those Lagrangian methods you use to solve constrained optimisation problems, i mean hardcore complex analysis. I remember asking my brother what exactly economics was. You wanna know what he said? He said, its all about solving the constrained optimisation model. What a shame, this is how bad the problem in economics has become. He said, 95% of microeconomic problems are solved by solving a constrained optimisation problem. Embarrassing, thats all I have to say about economics, simply embarrassing.
Learning at Imperial College London
Imperial College London
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But by the same virtue when some people ask you "what is Newtonian physics?" I bet most people would just quote F = dp/dt where p = mv is momentum. Even worst, some may just say F = ma... automatically assuming constant mass such that dm/dt = 0

Physics has also long degraded into solving mathematical equations, but is works very well I heard, especially in those more theoretical situations like quantum mechanics, where it defies the human intuition and common sense.
MoBstar
Shady i know its shocking, but for once your right :biggrin:. As i have said numerous times on this thread (???:biggrin:???), solving mathematical equations all semester is not gonna do anything to your economic intuition. If you wanna do maths, do maths, and i mean proper maths, not all those Lagrangian methods you use to solve constrained optimisation problems, i mean hardcore complex analysis. I remember asking my brother what exactly economics was. You wanna know what he said? He said, its all about solving the constrained optimisation model. What a shame, this is how bad the problem in economics has become. He said, 95% of microeconomic problems are solved by solving a constrained optimisation problem. Embarrassing, thats all I have to say about economics, simply embarrassing.

Wow... so is economics very closely related to physics?

Another curious fact that I have to agree with: BSc Physics students can go on to read MSc Maths, but BSc Econs students cannot read MSc Maths (as in get admitted into the programme, esp. for the more pure topics.)

I know the physics students do a very substantial amount of maths. How true is that to econs students. Do they still write economics essays like they did at A-level?
spencer11111
But by the same virtue when some people ask you "what is Newtonian physics?" I bet most people would just quote F = dp/dt where p = mv is momentum. Even worst, some may just say F = ma... automatically assuming constant mass such that dm/dt = 0



Yes, but the point is that F = dp/dt is a complete description of what is happening when something feels a force. Of course you can embellish it by adding all sorts of analogies and giving a qualitative description, but this is just to facillitate learning not because it offers anything to the result.

The equations used in economics, by contrast, are not complete descriptions of economic situations. People and firms do not solve perfect information constrainted optimisation problems the whole time, just as the IS equation does not capture everything that is going on in an economy and the Philips curve does not give an absolute picture of unemplyment and inflation. In much of physics, the maths is what is actually happening. In economics the maths is forced onto observations to rationalise complex behaviour, but it does not come from the observations themselves.
spencer11111
Wow... so is economics very closely related to physics?

Another curious fact that I have to agree with: BSc Physics students can go on to read MSc Maths, but BSc Econs students cannot read MSc Maths (as in get admitted into the programme, esp. for the more pure topics.)

I know the physics students do a very substantial amount of maths. How true is that to econs students. Do they still write economics essays like they did at A-level?


No physics and economics are not related. Maybe you're thinking of Lagrangian mechanics. This has nothing to do with Lagrange multipliers which are a very narrow part of static optimisation, which in turn is not used much by physicists. Physics students can go on to do maths courses because they do a lot of maths in their degrees, a lot more than any economist. There are huge areas of applied mathematics (complex analysis, vector calculus, PDEs) that someone on an economics degree is unlikely to ever encounter. Additionally, most physicists actually use thei mathematics they learn in their physics courses the whole time. If you're doing a course on vibrations and waves, you'll actually be solving differential equations. Economists might learn these things in their maths classes, but it's unlikely they'll ever see anything more than differentiation properly used in an economics module.
Davetherave
Yes, but the point is that F = dp/dt is a complete description of what is happening when something feels a force. Of course you can embellish it by adding all sorts of analogies and giving a qualitative description, but this is just to facillitate learning not because it offers anything to the result.

The equations used in economics, by contrast, are not complete descriptions of economic situations. People and firms do not solve perfect information constrainted optimisation problems the whole time, just as the IS equation does not capture everything that is going on in an economy and the Philips curve does not give an absolute picture of unemplyment and inflation. In much of physics, the maths is what is actually happening. In economics the maths is forced onto observations to rationalise complex behaviour, but it does not come from the observations themselves.

But I would say that most of the time the physics equations also do not really work out in experiments. We just make too many assumptions most of the time. Like for heat capacity experiments, we just assume zero heat lost to surroundings, which is false in most of the case.
Physics has slowly evolved from trying to explain the behaviour of the physical world qualitatively to just equations that describe the behaviour of things.

The equations in physics education are the core of the things, and the descriptions are only secondly.
spencer11111
But I would say that most of the time the physics equations also do not really work out in experiments. We just make too many assumptions most of the time. Like for heat capacity experiments, we just assume zero heat lost to surroundings, which is false in most of the case.


Well maybe so, but these approximations still work. We still understand heat capacities and thermodynamics in general to a level that allows us to use that understanding to do lots of marvellous things.

Of course things like heat loss, air resistance are often abstracted away, but at the end of the day your experiment still produces a value pretty close to c=4200 and your projectiles fly in parabolas. These things can easily be reinserted into the equations, they just make things a bit more messy.
spencer11111
Physics has slowly evolved from trying to explain the behaviour of the physical world qualitatively to just equations that describe the behaviour of things.

The equations in physics education are the core of the things, and the descriptions are only secondly.


Probably, but that can only be a criticism of the way physics is taught, not of the nature of the subject itself, or the things it sets out to achieve (uncover the rules of nature). Nature appears to behave in mathematical ways, so you cannot fault the subject for its quantitative approach.
Davetherave
Well maybe so, but these approximations still work. We still understand heat capacities and thermodynamics in general to a level that allows us to use that understanding to do lots of marvellous things.

Of course things like heat loss, air resistance are often abstracted away, but at the end of the day your experiment still produces a value pretty close to c=4200 and your projectiles fly in parabolas. These things can easily be reinserted into the equations, they just make things a bit more messy.

I guess the quantification of economics is a much harder task than mathematics, since it is describing the behavior of a potential complex group --- human beings. Human beings can be affected by things like news and so on.

But would it come to a time when all can be fitted into an equation that takes the relevant form and correct coefficients?
Davetherave, your posts are very insightful, by the way. :smile:
spencer11111
I guess the quantification of economics is a much harder task than mathematics, since it is describing the behavior of a potential complex group --- human beings. Human beings can be affected by things like news and so on.

But would it come to a time when all can be fitted into an equation that takes the relevant form and correct coefficients?


No it's because human beings act irrationally and are emotionally very stupid. It's hard-to-impossible for mathematics to capture this emotion and 'model' it. As the saying goes "a person is smart, but people are stupid".


Physics has slowly evolved from trying to explain the behaviour of the physical world qualitatively to just equations that describe the behaviour of things.

The equations in physics education are the core of the things, and the descriptions are only secondly.


Not sure what point you are trying to make, but I presume you are saying physics is better off for being less qualitative?

Physics is a combination of qualitative reasoning, physical intuition and mathematical competence. If physics were just all maths, technically physicists would become mathematicians. There is nothing we learn in our degrees that would be impossible for a mathematician to comprehend from the mathematics point of view, but a good mathmo =/= a good physicist (and vice versa) because physics is a bit more than pure maths.

Core equations are a compact form of stating theories in a mathematical language, but on their own they are meaningless.

Here is the Schrodinger Equation:

http://en.wikipedia.org/wiki/Image:s-smilie:chrodinger_Equation.jpg


If I were to now tell you "this equation tells us everything about the quantum world that we could possibly want to know", you'd be a bit stumped because in fact, it tells you nothing in the grand scheme of things (even if you understood the notation and each of the terms). The entire electromagnetic theory (a very big theory!) can be collapsed into 1 equation and you can say "here is everything you need to know about electromagnetics", but it's meaningless. What a lot of people misunderstand about physics is that it's a lot of mathematics with qualitative understanding, and then being able to re-represent that in different situations.

Do I think A-levels are ridiculously light on the maths? YES! It's pathetic as it leaves out the maths and gives you definitions to learn. But qualitative reasoning will always be a part of physics, together with the maths.

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