经济学人下载:代代叠加:庞氏骗局(2)

A second consideration is demography.
第二个考虑是人口。

A growing population creates a natural pyramid scheme.
不断增长的人口创造出一个天然的金字塔式的骗局。

Each cohort of participants will receive the money contributed by a later, larger generation.
每一代的参与者都会收到由后来的、人口更大的一代人出资的钱。

Therefore they too can get more out of it than they put in.
因而，他们也可以从中得到比他们投入的还要多的东西。

Future generations may also be better off than their predecessors.
未来的几代人也可能比他们的前辈过得更好。

They may benefit from sources of economic advance (such as improved technology) over and above simple capital accumulation.
他们可能从超越和高于简单的资本积累的经济进步（如提高了的技术）的源头中获益。

This march of progress should allow a Ponzi scheme to pay a positive return to investors even if the scheme only takes a constant percentage from each generation's income.
这种进步应当允许庞氏骗局即便是在骗局从每一代人的收入中筹集固定的百分比的情况下也能够向投资者支付一笔正回报。

Thanks to economic growth, 10% collected from the incomes of today's young will be worth more than the 10% collected in the past from their parents' poorer generation.
鉴于经济的增长，从当今年轻人的收入中筹集的10%会比从他们更穷的父辈那里筹集来的10%更值钱。

To make things concrete, suppose a country's population grows by 1% a year and incomes per person grow by 4%.
为了使之具体化，假设，某国人口每年增长1%，人均收入每年增长4%。

In this case, a Ponzi scheme can offer an annual return of about 5% indefinitely, simply by taking a steady share of each generation's income.
在这种情况下，庞氏骗局单靠从每一代人的收入中提取稳定的份额，就可以无限期地提供5%左右的年化回报。

If the economy already has a large stock of capital, the return on saving and investing might be less than that, especially given the risk involved.
如果经济体早已具有大量的资本，储蓄和投资的回报可能有所减少，尤其是在考虑到其所涉及的风险时。

Such an economy would suffer from what economists call “dynamic inefficiency”.
这样的经济体会饱受经济学家所说的“动态无效率”（dynamic inefficiency）之苦。

In these circumstances, an intergenerational Ponzi scheme can be sustainable and desirable.
在这些条件下，代际庞氏骗局可以是可持续的、可取的。

A PAYG pension is only the most obvious example of such a scheme. Government debt can play a similar role (a possibility entertained by Peter Diamond of MIT in a 1965 paper building on Samuelson's insights).
现收现付养老金是这类骗局中唯一的最显而易见的例子。政府债务可以扮演类似的角色（这是由麻省理工的彼得·戴蒙德在1965年的一篇以萨缪尔森的深刻见解为基础的论文中提出来的一种可能性）。

If the government does not want to extract social-security contributions from the young, it can sell them long-term bonds instead.
如果政府不想从年轻人那里提取社保出资，它可以向他们销售长期债券作为替代。

When these bonds mature, the government can repay them by selling a fresh round of bonds to the next, richer generation.
当这些债券到期时，政府可以通过向更富有的下一代销售新一轮债券的方式偿还给他们。