Great Comments!Re: 张五常悼杨小凯 - 未名空间MITBBS历史存档

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Great Comments!Re: 张五常悼杨小凯

Great Comments!Re: 张五常悼杨小凯# Economics - 经济

n*e2004-07-13 07:07

1 楼

Steve Cheung's comments are trenchant. Once a while ago, I couldn't accept
Steve's ideas about economics. I thought economics should be explained by
mathematical models. After I aced advanced macro&micro and read several micro
books and the Chinese book <> written by Steve, I
tended to re-think about Steve's ideas. His comments about Yang Xiaokai are
mostly agreeable. And if you read Xiaokai's latter aritcles, you'll notice
that he has realized his problems and has writ

w*g2004-07-13 07:07

2 楼

economic sense and math skills never contradict each other. instead, we see
many great people who are good at both.
and math is a better than most existing languages in expressing complicated
interaction between complicated agents, i.e., human being, in most of times.
if an idea can be illustrated fully by english, then no math is needed. but
unfortunately, english is not sufficient for many modern economic ideas.
and logic thinking and rigourous derivation is not equal to math.

【在 n****e 的大作中提到】

: Steve Cheung's comments are trenchant. Once a while ago, I couldn't accept
: Steve's ideas about economics. I thought economics should be explained by
: mathematical models. After I aced advanced macro&micro and read several micro
: books and the Chinese book <> written by Steve, I
: tended to re-think about Steve's ideas. His comments about Yang Xiaokai are
: mostly agreeable. And if you read Xiaokai's latter aritcles, you'll notice
: that he has realized his problems and has writ

n*e2004-07-13 07:07

3 楼

I am a statistician. And I totally understand the importance of mathmatics.
However, sometimes mathmatics is far more unneccessary than concise language,
no matter English or Chinese. I also don't think there even exists MODERN
economics. Math is a good tool to study economics but not the only one. I met
an interesting problem one day and I got the answer right away by simple
reasoning and later I thought if use math to solve it, it looks almost
impossible because of the mathmatical complexity.

【在 w*****g 的大作中提到】

: economic sense and math skills never contradict each other. instead, we see
: many great people who are good at both.
: and math is a better than most existing languages in expressing complicated
: interaction between complicated agents, i.e., human being, in most of times.
: if an idea can be illustrated fully by english, then no math is needed. but
: unfortunately, english is not sufficient for many modern economic ideas.
: and logic thinking and rigourous derivation is not equal to math.

w*g2004-07-13 07:07

4 楼

I am interested in the interesting problem you got the answer right away by
simple reasoning but impossible by math. do enlishten me, thanks!

【在 n****e 的大作中提到】

: I am a statistician. And I totally understand the importance of mathmatics.
: However, sometimes mathmatics is far more unneccessary than concise language,
: no matter English or Chinese. I also don't think there even exists MODERN
: economics. Math is a good tool to study economics but not the only one. I met
: an interesting problem one day and I got the answer right away by simple
: reasoning and later I thought if use math to solve it, it looks almost
: impossible because of the mathmatical complexity.

n*e2004-07-13 07:07

5 楼

There are a handful interesting problems. Let me list one here. In June, the
gas price reached the historically highest point. I bought gas from SAM's
Club's gas station once. At regular gas stations, the typical 93 gas price is
$2.15, the typical 87 gas price is $2.03, and the difference is $0.12. At
SAM's Club, 93 gas is $2.02, 87 gas is $1.99, and the difference is only
$0.03. Why Sam's Club's gas has a lower price difference than the typical gas
station?
I had several plausible answers for t

【在 w*****g 的大作中提到】

: I am interested in the interesting problem you got the answer right away by
: simple reasoning but impossible by math. do enlishten me, thanks!

w*g2004-07-13 07:07

6 楼

this is not a complete problem, it has dependent variable only.
many models have been developed concerning price differentials using game-
theoretical technique.
the ideas underlying the models do not come from any math, but describling
them usually need game-theory which involves college math most of the time.

【在 n****e 的大作中提到】

: There are a handful interesting problems. Let me list one here. In June, the
: gas price reached the historically highest point. I bought gas from SAM's
: Club's gas station once. At regular gas stations, the typical 93 gas price is
: $2.15, the typical 87 gas price is $2.03, and the difference is $0.12. At
: SAM's Club, 93 gas is $2.02, 87 gas is $1.99, and the difference is only
: $0.03. Why Sam's Club's gas has a lower price difference than the typical gas
: station?
: I had several plausible answers for t

n*e2004-07-13 07:07

7 楼

That is why I said: sometimes mathmatics is far more unneccessary than concise
language, no matter English or Chinese. BTW, do you want to hear one of my
explainations of this price difference problem?

the
is
gas
with
by

【在 w*****g 的大作中提到】

: this is not a complete problem, it has dependent variable only.
: many models have been developed concerning price differentials using game-
: theoretical technique.
: the ideas underlying the models do not come from any math, but describling
: them usually need game-theory which involves college math most of the time.

w*g2004-07-13 07:07

8 楼

let me draw an analogy. math, or more precisely game-theory skill, is like
Nei4 li4. u do not need (though u can) use it for, say patting a fly, but
definitely need it for chopping a forest. explaining complicated ideas using
only languases like english is susceptible different reader interpretation.
i donot know what u want to explain; again it is not a problem yet. u need
to state the independent variable(s) before u need to explain it.

【在 n****e 的大作中提到】

: That is why I said: sometimes mathmatics is far more unneccessary than concise
: language, no matter English or Chinese. BTW, do you want to hear one of my
: explainations of this price difference problem?
:
: the
: is
: gas
: with
: by

n*e2004-07-13 07:07

9 楼

The question is: Why Sam's Club's gas has a lower price difference than the
typical gas station? If you want to answer it with a model, you need to make
your own assumptions and find your own variables (dependent or independent).
Just give me any explaination with your assumptions. That's it.
If I ask you "how does business cycle form", don't tell me this is not a
problem because there's no independent variable or such and such. Don't you
think such kind of economist is a pedant?

concise
game-

【在 w*****g 的大作中提到】

: let me draw an analogy. math, or more precisely game-theory skill, is like
: Nei4 li4. u do not need (though u can) use it for, say patting a fly, but
: definitely need it for chopping a forest. explaining complicated ideas using
: only languases like english is susceptible different reader interpretation.
: i donot know what u want to explain; again it is not a problem yet. u need
: to state the independent variable(s) before u need to explain it.

w*g2004-07-13 07:07

10 楼

u made the point. people seeing only math but not the thought process
underlying the math think it is all about math. interestingly, most of the
game-theoretical models use no more than college math. understanding this
math does not entitle one to understand the intellectually value of the model
illustrated by the simple math; then people tend to blame math.

n*e2004-07-13 07:07

11 楼

I followed waithing's way to get the answer. It's not mine.
By the way: Sometimes, abstract = complicate. For instance, abstract painting
is very complicate for me to appreciate it.

begin
the
make
independent).
you
like
but
need
of
the

n*e2004-07-13 07:07

12 楼

Now, you admit there is thought underlying math.
And you need to revisit my point: sometimes mathmatics is far more
unneccessary than concise language, no matter English or Chinese. Math is a
good tool to study economics but not the only one.
And till now, you can't answer a simple economic question I raised yet. Don't
stick to math! Stick to economics!!!

model
begin
It
the
make
independent).
you

【在 w*****g 的大作中提到】

: u made the point. people seeing only math but not the thought process
: underlying the math think it is all about math. interestingly, most of the
: game-theoretical models use no more than college math. understanding this
: math does not entitle one to understand the intellectually value of the model
: illustrated by the simple math; then people tend to blame math.

t*e2004-07-13 07:07

13 楼

so what is your answer? this price difference has puzzled me for some time le.

concise
time.
SAM's
price
At
typical
away

【在 n****e 的大作中提到】

a*n2004-07-13 07:07

14 楼

let me try try...
ppl who buy premium gas are usually richer and Sam's can make more money
out of their purchases of other stuff at Sam's...
so it is a way of attraching relatively affluent ppl to come over to Sam's
for gas and very possibly grocery shopping...

【在 t*****e 的大作中提到】

: so what is your answer? this price difference has puzzled me for some time le.
:
: concise
: time.
: SAM's
: price
: At
: typical
: away

n*e2004-07-13 07:07

15 楼

This could be an answer. But Sam's club grocery shopping needs membership
card, therefore, low gas price difference won't affect on the shopper flow
anyway: in a short period, the shopper number is almost fixed to the
membership number. Moreover, I went there to fill my tank only and I found
many cars just drove off the road and filled the tank and drove away.
Finnally, if to attract affluent ppl, 5 cents of price drop is quite enough.
I did have many answers and I think this one is most possibl

【在 n****e 的大作中提到】

z*i2004-07-13 07:07

16 楼

no one is bashing him this time.
it is just that Yang Xiao Kai just died. It is not that appropriate to make
such kind of critisism, which seems a little too arrogant, at this particular
moment.
Everyone knows Steven Cheung is an talented economist. But it is true that
sometimes he is too radical and arrogant in terms of persisting his own ideas.
He can claim what he believes, do research on those and show people his
research result. But criticizing other people and without too much ground but
c

【在 n****e 的大作中提到】

: This could be an answer. But Sam's club grocery shopping needs membership
: card, therefore, low gas price difference won't affect on the shopper flow
: anyway: in a short period, the shopper number is almost fixed to the
: membership number. Moreover, I went there to fill my tank only and I found
: many cars just drove off the road and filled the tank and drove away.
: Finnally, if to attract affluent ppl, 5 cents of price drop is quite enough.
: I did have many answers and I think this one is most possibl

T*x2004-07-13 07:07

17 楼

membership
station
87
regular
one
Especially
这个因素对sam's和其他加油站同样起作用，
不能解释sam's的油价差比其他加油站的油价差小。
(this
gas
to
这个因素也是对sam's和其他加油站同样起作用。
也不能解释油价差的不同。
do
as
examples
我同意你的看法：很多问题不必用数学模型。
the

【在 n****e 的大作中提到】

n*e2004-07-13 07:07

18 楼

enough.
will
the
frequent
will
They are different. For Sam's club, each refilling will bring extra influence
on it's grocery business, while other gas station can refill at any time. I
noticed that many grocery stores choose night to re-stock the shelves. This is
because the re-stocking cost is too high in the day.
will
the
and
They are also different. Other major gas brand produce gas by their own group.
But Sam's has to buy from the gas producer or distributor. I noticed that some
small gas s

【在 T*******x 的大作中提到】

:
: membership
: station
: 87
: regular
: one
: Especially
: 这个因素对sam's和其他加油站同样起作用，
: 不能解释sam's的油价差比其他加油站的油价差小。
: (this

w*g2004-07-13 07:07

19 楼

in "explanation 1", u assume that sam's club is stupid, in not stocking
enough 87 fuel but having to giving up margin on the better 91 fuel. this is
not
true. first, sam's club can simplely stock enough. second, it can simply
increase 87's price to discourage oversale. then more people will switch to
the better fuel, which then allow sam's to charge more for the better 91 fuel.
so it is just not clear how the price difference will move. this is just a
standar second-order price discrimination pr

【在 n****e 的大作中提到】

:
: enough.
: will
: the
: frequent
: will
: They are different. For Sam's club, each refilling will bring extra influence
: on it's grocery business, while other gas station can refill at any time. I
: noticed that many grocery stores choose night to re-stock the shelves. This is
: because the re-stocking cost is too high in the day.

n*e2004-07-13 07:07

20 楼

~~87 and 91 tanks are already built in, it's very hard or impossible to change
part of 91 tank to store 87. So, they can't give up 91 margin. Because of the
extremely high demand of gas, even normally enough 87 stock will become
insufficient.
fuel.
~~Since the 87 price is 4 cents below the regular price, in order to attract
consumers (only 2 cents cheaper than the regular price) and in order to
satisfy members (2 extra cent drop because members paid membership fee), Sam's
has no room to increas

【在 w*****g 的大作中提到】

: in "explanation 1", u assume that sam's club is stupid, in not stocking
: enough 87 fuel but having to giving up margin on the better 91 fuel. this is
: not
: true. first, sam's club can simplely stock enough. second, it can simply
: increase 87's price to discourage oversale. then more people will switch to
: the better fuel, which then allow sam's to charge more for the better 91 fuel.
: so it is just not clear how the price difference will move. this is just a
: standar second-order price discrimination pr

w*g2004-07-13 07:07

21 楼

is
change
the
to
Sam's
what is the "room"? competitition from other stores, or the price for 91? in
either case, u r implying that sam can not increase 87 price over the room.
but this contradict the assumption that sam is over-selling 87. for the
over-demand to be true, it must be that sam will not lose too much 87 sales by
increasing its price even quite some. so, sam can simply increase 87's price.
if u worry that consumers may switch to 91, then simply increase 91's price as
well (to increa

【在 n****e 的大作中提到】

:
: ~~87 and 91 tanks are already built in, it's very hard or impossible to change
: part of 91 tank to store 87. So, they can't give up 91 margin. Because of the
: extremely high demand of gas, even normally enough 87 stock will become
: insufficient.
: fuel.
: ~~Since the 87 price is 4 cents below the regular price, in order to attract
: consumers (only 2 cents cheaper than the regular price) and in order to
: satisfy members (2 extra cent drop because members paid membership fee), Sam's
: has no room to increas

n*e2004-07-13 07:07

22 楼

attract
by
price.
as
is
just
~~Even though somebody might take your strategy, it's still to lower the price
difference to balance 87 and 91 sells. Let me tell you why Sam's were not
willing to increase the 87 price. At that time, all levels of gases were over
$2.00, it's $1.99 87 gas was a superb advertisement for its gases. Why bother
not to take this advantage by just lowering a little price of 91?
u
91
~~As I said, Sam's sells gas to both members and non-members. This condition
is the same a

【在 w*****g 的大作中提到】

:
: is
: change
: the
: to
: Sam's
: what is the "room"? competitition from other stores, or the price for 91? in
: either case, u r implying that sam can not increase 87 price over the room.
: but this contradict the assumption that sam is over-selling 87. for the
: over-demand to be true, it must be that sam will not lose too much 87 sales by

w*g2004-07-13 07:07

23 楼

u r using edogenous forces to make ur explanation while assuming them
exogenous, i.e., advertisement, binding by the supplier. all these effects
should be endogenous, that is, u should ask why and how signaling low-price
image by fixing the 87 price may affect sam's profits, why and how should the
supplier bind the products, and whether sam should accept a particular
binding. all these have profound effect on the equilibrium price difference u
r worrying about. so just assuming that sam or other

【在 n****e 的大作中提到】

:
: attract
: by
: price.
: as
: is
: just
: ~~Even though somebody might take your strategy, it's still to lower the price
: difference to balance 87 and 91 sells. Let me tell you why Sam's were not
: willing to increase the 87 price. At that time, all levels of gases were over

T*x2004-07-13 07:07

24 楼

influence
is
Another
这样解释就成立了。

【在 n****e 的大作中提到】