zaishiweikexuewomenyeyaoxuexia
zhiyaonishixuejingjide

似乎这是高鸿业在他的教科书中的观点！我认为经济学还是有其有用之处的，凯恩斯主义所开创的国家干预经济的思路和研究国民经济整体的做法是可取的，而运用数学在经济研究当中则是十分必要的，楼主不要太激进了！

如果宏观经济学真能被证伪，那它还真是科学的啦

http://www.nytimes.com/2009/09/06/magazine/06Economic-t.html?_r=1
http://modeledbehavior.com/2009/ ... -krugman-full-text/

经鉴定 LZ是 个小丑

是的   计量经济学其实也很伪科学

应该说现代宏观经济学中有一部分是伪科学

6# prinski 之所以取e的nt次方那是因为指数增长，复利效应，微积分最开始里面的两个极限公式有介绍。

在某种程度上，经济学的显学地位是这么学科招致如此多口水的重要原因~

钱不是万能的，而没有钱是万万不能的！

模型也不是万能的，而没有模型也是万万不能的！

还是好好学习吧。根本不懂宏观经济学就不要先否定。应该先学懂了，才有资格否定。

经济学研究总是滞后的，而且总是为解释现实而研究理论。。。

绝对的标题党！

不是新古典的问题，是凯恩斯的错。


Or perhaps Krugman’s point is that a cabal of obvious crackpots bedazzled all of macroeconomics with the beauty of their mathematics, to the point of inducing policy paralysis. Alas, that won’t stick. The sad fact is that few in Washington pay the slightest attention to neo-classical or intertemporal ideas. Paul’s simple Keynesianism has dominated policy analysis for decades and continues to do so. From the CEA to the Fed to the OMB and CBO, everyone just adds up consumer, investment and government “demand” to forecast output and uses simple Phillips curves to think about inflation. If a failure of ideas caused bad policy, it’s Keynes’ ideas that failed. （摘自第二个链接）

克鲁格曼，先回去读读文献再扯。

The future of economics.

How should economics change? Krugman argues for three incompatible changes.


First, Krugman argues for a future of economics that “recognizes flaws and frictions,” and incorporates alternative assumptions about behavior, especially towards risk-taking. To which I say, “Hello, Paul, where have you been for the last 30 years?” Macroeconomists have not spent 30 years admiring the eternal verities of Kydland and Prescott’s 1982 paper. Pretty much all we have been doing for 30 years is introducing flaws, frictions and new behaviors, especially new models of attitudes to risk, and comparing the resulting models, quantitatively, to data. The long literature on financial crises and banking which Krugman does not mention has been doing exactly this bidding for the same time.


以上摘自第二个链接

克鲁格曼，端起碗吃饭放下碗骂娘不厚道啊，知道你得了诺奖，也不能太自私吧。


Third, and most surprising, is Krugman’s Luddite attack on mathematics; “economists as a group, mistook beauty, clad in impressive-looking mathematics, for truth.” Models are “gussied up with fancy equations.” I’m old enough to remember when Krugman was young, working out the interactions of game theory and increasing returns in international trade, and the old guard tut-tutted “nice recreational mathematics, but not real-world at all.” How quickly time passes.

我也开始觉得定量分析越来越不是那么一回事了

不用数学行吗？问题是我们的数学不够用！


Again, what is the alternative? Does Krugman really think we can make progress on his – and my – agenda for economic and financial research — understanding frictions, imperfect markets, complex human behavior, institutional rigidities – by reverting to a literary style of exposition, and abandoning the attempt to compare theories quantitatively against data? Against the worldwide tide of quantification in all fields of human endeavor (read “Moneyball”) is there any real hope that this will work in economics?


No, the problem is that we don’t have enough math. Math in economics serves to keep the logic straight, to make sure that the “then” really does follow the “if,” which it so frequently does not if you just write prose. The challenge is how hard it is to write down explicit artificial economies with these ingredients, actually solve them, in order to see what makes them tick. Frictions are just bloody hard with the mathematical tools we have now.

经济学家也是有道德的啊，小克你这样曲解我太不地道了吧。Lucas算是你师爷吧，你都敢嘲笑，别以为Dornbush去了就没人敢管你这个debunker了。

The level of personal attack in this article, and fudging of the facts to achieve it, is simply amazing.


As one little example (ok, I’m a bit sensitive), take my quotation about carpenters in Nevada. I didn’t write this. It’s a quote, taken out of context, from a bloomberg.com article written by a rather dense reporter who I spent about 10 hours with patiently trying to explain some basics. (It’s the last time I’ll do that!) I was trying to explain how sectoral shifts contribute to unemployment. Krugman follows it by a lie — I never asserted that “it take mass unemployment across the whole nation to get carpenters to move out of Nevada.” You can’t even dredge up a quote for that monstrosity.


What’s the point? I don’t think Paul disagrees that sectoral shifts result in some unemployment, so the quote actually makes sense as economics. The only point is to make me, personally, seem heartless — a pure, personal, calumnious attack, having nothing to do with economics.


Bob Lucas has written extensively on Keynesian and monetarist economics, sensibly and even-handedly. Krugman chooses to quote a joke, made back in 1980 at a lunch talk to some business school alumni. Really, this is on the level of the picture of Barack Obama with Bill Ayres that Sean Hannity likes to show on Fox News.

学着累啊·~

佩服lz勇气

呵呵 经济学试图学物理学的方法 但社会现象与自然现象决然不同

小克你不会不知道吧，我们的模型就是为了简化以清楚地说明一个问题，现实世界更复杂，你倒好，不但不跟老百姓说明白，反倒掉转枪口。你也不想想自己年青时不也这么过来的，现在翅膀硬了？至于拿利益集团的钱，你这不要脸的媒体经济学家，我们都没说你还给了你一个炸药将，你还好意思朝我们仍石头，真是乌鸦站在猪身上！


It goes on. Krugman asserts that I and others “believe” “that an increase in government spending cannot, under any circumstances, increase employment,” or that we “argued that price fluctuations and shocks to demand actually had nothing to do with the business cycle.” These are just gross distortions, unsupported by any documentation, let alone professional writing. And Krugman knows better. All economic models are simplified to exhibit one point; we all understand the real world is more complicated; and his job is supposed to be to explain that to lay readers. It would be no different than if we were to look up Paul’s early work which assumed away transport costs and claim “Paul Krugman believes ocean shipping is free, how stupid” in the Wall Street Journal.


Of course the idea that any of us do what we do because we’re paid off by fancy Wall Street salaries or cushy sabbaticals at Hoover is just ridiculous. (If Krugman knew anything about hedge funds he’d know that believing in efficient markets disqualifies you for employment. Nobody wants a guy who thinks you can’t make any money trading!) And given Krugman’s speaking fees and how much the looney right likes him, it’s a surprising first stone for him to cast.

克鲁格曼已经做了经济学届的逃兵，彻底地沦落成利益集团的代言人，鉴定完毕。

How did Krugman get it so wrong?

So what is Krugman up to? Why become a denier, a skeptic, an apologist for 70 year old ideas, replete with well-known logical fallacies, a pariah? Why publish an essentially personal attack on an ever-growing enemies list that now includes practically every professional economist? Why publish an incoherent vision for the future of economics?
The only explanation that makes sense to me is that Krugman isn’t trying to be an economist, he is trying to be a partisan, political opinion writer. This is not an insult. I read George Will, Charles Krauthnammer and Frank Rich with equal pleasure even when I disagree with them. Krugman wants to be Rush Limbaugh of the Left. I still want to be Milton Friedman, but each is a worthy calling.

谁说宏观经济学没用？
很多考试都考这个，能说没用吗？

       首先我想说明的是，我也只是个大学本科二年级的经济学学子，对高级宏观经济学不甚了解，但是我认为许多初级教材有失偏颇的原因在于，即要做到教材的简明易懂，又要培养学生科学性的严密思维，才造成如今初级宏观经济学数理推断的画蛇添足现象。对此国外教材的做法是将这些数学公式全部略去，而等到学生在博士阶段继续读研时，才将复杂的数学公式映入。对此我需要解释的是并不是国外本科生的数学基础不好，只是国外教授认为，对于经济学子们过早接触数理公式会使他们忽视经济本身的含义与运行机理，所以他们将这一部分挪到了研究生教育阶段了。所以在美国，有志于成为经济学家的本科生都会在大学初期选修很多高等数学的学科，以进一步扎实其数理功底。
       第二点，我认为经济学家本身的建模过程其方式也的确存在问题。一个很好的例子便是索咯条件和效率工资模型（George Akeflot at UC Berkeley首次提出，其后又被索咯，斯蒂格利茨等人完善。）
“效率工资理论是对劳动力市场为什么会处于非瓦尔拉斯均衡状态的其中一个解释。及企业支付的工资水平高于竞争性市场上均衡工资水平。后来的新凯恩斯主义者则与20世纪70年代引入效率工资概念用以解释劳动力市场工资调整机制失效以及非自愿失业现象。其中的一位著名的诺贝尔经济学奖得主索洛提出了著名的索洛条件，用以解释工资刚性的成因。”（见孙敬水的《中级宏观经济学》）
1，
索洛条件：索洛在《工资刚性的另一个可能来源》（1979）中提出：降低工资的成本将会超过因为工资降低所带来的收益的损失。降低工资至少会引起1，道德风险2，企业名誉下降3，招募员工产生逆向选择行为。
以下是索洛条件的数学表达式：
Y=Sf(e(w) L)
p=PY―wL―K
¶p/¶L=PsF(e(w) L)e(w) ―w=0
¶p/¶w=PsF(e(w) L)Le¢
(w) ―L=0
由上式可得：w*/ e(w*)=1/e¦¢ (w*)




    然而正如下图所示：横坐标上的E代表的是员工的努力程度，问题便随之产生。努力程度与效用一样，也很难用数字表示。何况员工的努力程度有许多因素所决定，其现实情况远吧没有索洛所阐述的那么简单明了！

限于篇幅原因，我想说的是，经济学作为社会科学的皇后，远没有许多人所述的那样“经济学帝国主义”。因为经济学的发展不断趋于如物理学的精密，然而经济学本身，所谓的经济学是建立在研究经济体的基础之上的科学。经济社会是纷繁复杂的，在这样一条通向真理的坎坷道路上，需要的是心理学，政治学，数学，环境学，社会学等学科的帮助，而不是简单的经济学帝国主义罢了！！~~~~所以经济学的模型需要融入更多其他科学的元素才能得以发展，如果只是靠我们一群经济学家在象牙塔里苦思冥想，是得不到真理的。其结果，被认为的所谓真理，往往是可笑的。至少凯恩斯也是这样认为的。

这个模型就是搞预测的，效果如何你仔细看完再说。当然，我猜得到你又会说“它预测得到经济危机吗”等等无穷无尽的循环问题。

我不得不说，这个模型要是什么都能宏观经济事件都能预测，它就反而不是科学的了，天文学家不是导到现在对宇宙的命运如何这种没多大“不确定性”的问题都还不知道确切答案的么。气候学家、地震学家对天气、地壳的预测不也只能做到很短期内的“预测么”，谁也没去否定二者的科学性。宏观经济预测之所以困难，就是在于有太多的“不确定性”问题，人们对于未来的信息和预期的掌握总是复杂而不完全的，因此经济预测尤其的困难。考虑到这些现实，目前的一些宏观经济模型确实是已经做得相当不错的了，何况这部分模型很多只是最简单的标准模型，还需要增加更多的细节。

我想说的是，无论现在宏观经济学是否是科学，对于人类社会的复杂社会经济问题，总需要一门学科去认真研究，你可以给他按上各种的学科名称，不一定非叫做宏观经济学，也可以叫“算命经济学”嘛，呵呵，但是不论叫什么，不论我们认为它是科学还是算命，不论这门学科是科学的还是伪科学的，都不能抹杀它的极端重要性——总要有人有学科去研究这个（宏观）经济问题。

话说到这儿，我的意思应该是很明白了，说为伪科学与否，对于经济学只是方法论意义上的概念，认为目前的方法论不科学，可以研究其他的方法论吗。目前中级以下教的是凯恩斯的方法论，高级就有了新古典的方法论，大家对目前的方法论的科学性不满，就用该的自己开发方法论，说不定能出现中国第一个诺奖呢！但是以这个学科不科学为借口而逃避深入学习和研究，就显得并不高尚了，如果是这样，那就“请你绅士一点，把嘴闭上然后走开”。——并没有特别指向意义。

唉　的确这些公式让学过数学的人看着可笑啊

数学只是个工具，但是显然没有几个人能像马克思一样有强大的抽象思维，自己建立起一个强大的概念体系来阐述问题。所以其他经济学家用数学来阐述问题，表达逻辑，能表达清晰就不错了。

楼主偏激了