As a shell-shocked world tries to fathom how its economic collapse happened, commentators are busily outbidding each other with claims about the exceptional nature of this crisis. But the most astounding fact is how familiar its physiognomy and physiology look compared to past financial crashes.

No one can read the chronicles of those earlier crashes without sensing – with a chill – that history is repeating itself. The story of the modern capitalist economy is a rhythmic repetition of cycles, syncopated by eerily similar crises. These crises, while their details differ, are but variations on the same theme. Easy money, geared up by leverage, floods the financial system through innovative products. This simultaneously pumps up asset prices and obscures their speculative nature, with euphoria usurping the place of analysis. Until, one day, something triggers a loss of confidence in the continued rise of prices, and the whole leveraged edifice crumbles.

Today's collapse has followed the same pattern – as outlined today in the FT's series on the future of capitalism. Easy money came from global macroeconomic imbalances that generated enormous capital inflows into deficit countries. Those flows helped drive interest rates down and increase access to credit, fuelling a leveraged asset bubble. Many leaders in the affected countries – in particular the US – knew this: Alan Greenspan himself spoke of “irrational exuberance”. And yet they did not understand how they had to act to prevent a replay of the past.

Today's disastrous outcome is testimony to those leaders' intellectual failure. Most fundamentally to blame is their unwillingness to see (or their wilful ignorance of) what markets need in order to produce good outcomes for society.

Every first-year economics student learns the conditions for an unregulated market, in theory, to function efficiently. The most important are full information, enforceable property rights and contracts, and the absence of “externalities” – effects of economic trans- actions on third parties. These conditions are never fulfilled, but many markets come close enough that participants' self-interested actions achieve good outcomes for all.

When these conditions are absent, markets malfunction; the way they do so is one of the great topics of economic theory. It tells those who care to listen that when a market is too opaque, or when the effects of market transactions are too inter- dependent, the pursuit of self-interest can make everyone worse off, or unfairly land some with the losses caused by others, or – in extremis – make markets disappear altogether. Nowhere are these problems greater than in financial markets.

Finance expands our economic possibilities by enabling us to shift funds between the present and the future, and between different outcomes of risky ventures. For that reason, confidence in future values is everything for a financial product: if confidence is lost, the market collapses. But in a non-transparent financial sector, unwarranted valuations will often occur, which, when they fail, can destroy confidence throughout the financial system. And the more implicated the economy is in the financial sector, the wider are the repercussions of such dysfunctions – to the point where financial failures can threaten the economic system as a whole.

Economic policymakers could have limited these dangers, but they did not do so. Instead, they allowed the bubble to inflate and let financial transactions become increasingly opaque and ever more leveraged. As in previous bubbles, value came to rely on the perception of value itself: growth pulling itself up by its own leveraged bootstraps. Many assets were not even priced through market trading but valued by complex formulas – akin to peddling tulips with equations.

People were not unaware of the risks, but both regulation and private risk management were based on the faulty premise that if each entity looks after its own risk, no one needs to worry about systemic risk. The great mistake was to rely merely on self-interest in as imperfect and as important a market as the financial sector. The huge profits bankers reaped reinforced their collective blindness to the illusory value of the assets they traded.

Those who sound the death knell of market capitalism are therefore mistaken. This was not a failure of markets; it was a failure to create proper markets. What is to blame is a certain mindset, embodied not least by Mr Greenspan. It ignored a capitalist economy's inherent instabilities – and therefore relieved policymakers who could manage those instabilities of their responsibility to do so. This is not the bankruptcy of a social system, but the intellectual and moral failure of those who were in charge of it: a failure for which there is no excuse.

在受到强烈震撼的世界试图弄清楚这场经济崩溃为何会发生的同时，各路评论家正争先恐后地抛出对本次危机异常特性的论断。但最令人震惊的事实是，从外表和结构上来看，这场危机与以往的金融危机是多么地相似。

读过那些早期危机的编年史后，人们无不感觉到——伴着一丝寒意——历史正在重演。现代资本主义经济的发展经历是一种有节律的周期往复，相似得令人恐惧的危机是其中间插的切分符。这些危机虽然细节各异，但都是同一个主题的变奏。在杠杆作用下迅速增加的轻而易举得来的钱财，借助创新产品注满了整个金融体系。这在推高资产价格的同时还模糊了它们的投机本质，狂热篡夺了冷静分析的位置。直到某一天，某件事情导致人们对价格的不断上升丧失信心，整座由杠杆构建的大厦便轰然倒塌。

当前这场衰退遵循了同样的模式——正如英国《金融时报》日前在“资本主义的未来”系列中所概述的那样。轻而易举得来的钱财来自导致巨额资金流入国际收支逆差国家的全球宏观经济的失衡。这些资金流导致利率下调、增加了信贷获取途径、引发了杠杆化资产泡沫。许多受影响国家的领导人——尤其是美国——都知道：艾伦•格林斯潘(Alan Greenspan)自己就曾谈到 “非理性繁荣”。然而，他们不明白自己怎样做才能防止过去的悲剧重演。

今天的灾难性后果就是那些领导人决策失败的明证。最根本的问题在于他们不愿意看清（或是他们有意忽视）市场需要什么才能产生对社会有利的结果。

每个经济系的大一学生都会学到，在理论上，一个不受监管的市场需要哪些条件才能有效运转。最重要的是完全信息、有法律约束力的物权和契约、以及没有“外部性”——即经济活动对第三方的影响。这些条件从未得到满足，但许多市场已与之非常接近，足以使参与者的利己行为取得对所有人都好的结果。

当这些条件缺失时，市场就失灵了；而市场失灵的方式是经济学理论的重要论题之一。它告诉那些在意并愿意聆听的人：当一个市场过于不透明，或是当市场活动的影响过于相互依赖时，追求私利会让所有人的情况变坏，或者有失公允地让某些人承担其他人造成的损失，或者——在极端情况下——让市场完全消失。这些问题在金融市场最为严重。

金融扩展了我们的经济可能性，让我们能够在现在与未来之间、在风险投资的不同结果之间转移资金。正因为此，对未来价值的信心就是金融产品的一切：一旦信心丧失，市场就会崩溃。但是，在一个不透明的金融部门里，没有根据的估值经常会出现，当它们失败时，就会摧毁整个金融体系的信心。而且，经济受金融部门的牵连越严重，这种功能失常的影响力就越广泛——以至于金融失灵可能威胁到整个经济体系。

经济政策制定者本来能够限制这些危险，但他们没有这么做。相反，他们听任泡沫不断膨胀，任由金融交易变得越来越不透明、杠杆率越来越高。与前几场泡沫一样，价值开始依赖于对价值本身的感觉：增长依靠自己本身的杠杆作用提升自己。许多资产甚至不是通过市场交易定价，而是借助复杂的公式——类似于用方程式来兜售郁金香。

人们并不是没有意识到风险，但监管和私人风险管理都基于一个错误的前提，即如果每个实体都能各自管理好自己的风险，就没有人需要担心系统性风险。他们最大的错误是，在金融部门这样一个如此不完善而又如此重要的市场中，仅仅倚仗个人利益的作用。银行斩获的巨额利润又加剧了它们对于所交易资产虚幻价值的集体性熟视无睹。

因此，那些敲响市场资本主义丧钟的人错了。这不是市场的失败，而是创造健全市场的失败。应该对此承担责任的是某种思维模式，这种思维模式在格林斯潘身上体现得最为明显。它忽略了资本主义经济内在的不稳定性，因此让那些原本能够控制住这种不稳定性的政策制定者得以脱卸责任。这不是一种社会体制的破产，而是社会体制管理者决策与道德的失败：这种失败是没有借口可寻的。

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