原创 2015-12-07 季天鹤央行观察央行观察
季天鹤方正中期研究院研究员、央行观察专栏作家

人民银行徐诺金老师的《优势突围》于2015年5月问世，全书分上中下三卷，收录了徐老师十几年来的观察与思考，特别是消费和投资的问题，给读者带来很多有益的启发。

人们在一段时期内（例如一年）生产出消费品流和投资品流。当年消耗的消费品流一般被看作当年的消费，当年所有的投资品流和留存的消费品流一般被看作当年的投资。这种看法，使消费和投资的总和，依然等于当年全部的消费品流和投资品流。如果把储蓄看作是产出流中没有被消耗的部分，那么储蓄当然就等于投资了。

如果用公式来表达上面的描述，便是：人们的产出流=消费品流+投资品流。由于消费品流未必被全部消耗掉，我们便有：产出流=消费品流的消耗+消费品流的留存+投资品流。而对于上述的三部分，人们一般都只把消费品流的消耗当作消费，因此我们有：产出=消费（消费品流的消耗）+投资（=存货投资即消费品流的留存+投资品流即固定资产投资等）。而如果产出流-消费=储蓄，那么显然就有储蓄=投资了。

如果过去留存到现在的消费品已经无法被消耗，过去留存到现在的投资品已经无法生产消费品，比如发霉了的大米和锈坏的机器，那么我们应该如何考虑上述消费品和投资品？人们为了抵御风险，会希望持有一定存量的消费品。而为了在下一年产生更多的消费品，人们也需要维持一定的投资品存量。大米霉变会降低消费品存量，机器锈坏会减少投资品存量，因此人们就需要通过多工作多生产，弥补大米存量的减少，以及机器的锈坏。

这里面存在一个荒谬的地方。如果社会希望一段时期内生产的东西越多越好，那么一种方式就是不停的破坏原来留下的东西，或者过去留下的东西不停的坏掉。去年建好一座桥，如果今年就不用建桥了，今年也就没有生产投资品了。而如果把去年建好的桥炸掉，或者去年建好的桥塌了，今年再建一遍，那么今年就又有了一轮新的投资，看起来反而比没桥可建有更多当期的产出。

比起先破坏再生产和修补豆腐渣，另外一种生产也很荒谬，那就是为生产而生产。人们一年能吃的东西是有限的，但是在地球上修的路还远没有达到极限。今年修的路，即使永远没有人走，也有助于实现今年的产出目标。以及，虽然人吃的东西是有限的，但吃不了的粮食并没有上限，于是人们可以生产很多粮食，堆在那里，这也有助于实现今年的产出目标。

上面的两个荒谬，其实揭示了目前的一些问题。中国人民很忙，各种东西总是在不停地坏，需要修理需要重置，路要重新刷重新修重新铺管线，新修的市政经常需要重建。不过令人“欣慰”的是，每次重复生产都会创造GDP。如果房子建好了几百年不用重建，那不就没有新GDP了么。不过问题来了，如果大家总这么忙，怎么有时间“常回家看看”呢？

GDP中的资本形成总额包括固定资本形成总额和存货变动。如果为了当期GDP好看而盲目扩大投资，其结果要么是留下了很多不会开工的工厂和不会走人的路（固定资产投资存量），要么是留下了很多卖不出去的东西（存货投资存量）。但事情的诡异之处在于，GDP是不衡量存量的，无论有多大的存货和闲置产能，也反映不到GDP上。只要不停地建工厂产存货，就有GDP。

在过去投资品和消费品都不足的时代，修了马路就有人走，生产的东西永远有销路，因此追求GDP不会留下一地的过剩产能和库存。但现在，修了马路未必有人走，生产的东西未必有销路，因此通过扩大投资来追求GDP，就会带来产能和库存的问题。或许有人说今年建了就建了，明年又是新的一年，但至少我们看到今年很多工作都是白忙活，大家完全可以休息。而在有钱有货币的世界里，负面影响还会更多。

但上述的荒谬并不意味着投资不重要。事实上中国仍然需要大量的投资来生产消费品，以满足大家需要，这也是徐老师在《优势突围》中的观点。人们需要教育服务、医疗服务、便捷出行服务、更好住宿服务等等，而这都需要对教育、医疗、交通、房地产等进行投资。没有投资，也就没有更多的消费。当然这里的投资，不是需要不停重建的低质量投资，也不是不能满足需要的闲置产能投资，更不是没人需要的产品的库存投资。未来的投资，将是消费引领下的投资，而不是为了胀大当期GDP而进行的投资。这大概是消费成为增长引擎的真实含义。

把消费和投资的内涵扩展到进出口在开放经济下，除了消费和投资，我们还要考虑进出口。如果中国在今年没有进口而有出口，意味着中国今年生产的消费品流和投资品流里面，一部分消费品流被国内消耗，一部分消费品流和投资品流被国内留存，一部分消费品流和投资品流被国外拿走，即当年本国产出流大于国内消耗和留存。如果中国只有进口没有出口，则中国今年除了自己生产的消费品流和投资品流，还把从外国来的消费品流和投资品流用于消耗或者留存，即当年本国产出流小于国内消耗和留存。

如果既有进口又有出口，则情况就是上述两者的结合。在一年当中，一些中国生产的东西跑到外国，一些外国的东西跑到中国，使得中国人能够消耗的消费品流、留存的消费品流以及投资品流，和中国当年生产的消费品流与投资品流，有了很多不同，即自己消耗和留存的自产消费品流和投资品流，比当年自产的消费品流和投资品流要少，同时还消耗和留存了国外的消费品流和投资品流。

那么净出口为正或为负意味着什么呢？我们先考虑白送和白拿的情况。如果中国在一年里，把很多东西白送给外国，虽然和出口看起来，都是当年的本国产出流大于本国消耗和留存，但中国出口意味着中国通过等价贸易，取得了换回外国一些东西的权利，只不过换回这个操作被推迟到未来，而白送则没有让中国取得未来换回外国东西的权利。

同样，白拿和进口虽然看上去都是在当年中，中国可以消耗的消费品流，以及可以留存的消费品流和投资品流，比自己生产的消费品流和投资品流多。但在白拿的情况中，外国不会获得未来提取中国消费品或投资品的权利，而在进口的情况下，由于外国在出口给中国东西时，作为等价交换也拿到了在未来换取中国消费品或投资品的权利，所以中国面临着在未来净出口的可能。

所以我们看到，现在的净出口，其实等同于把现在的一些产出流留存起来，用来推迟到未来消耗，只不过这里的留存方式，不是出口国在自己的地界上留存了自己生产的商品，而是在国外留存了提取国外商品的能力。这样来看，进出口其实可以被放到消费和投资的框架里，它要么可以被看作一种留存到未来的消费品，要么可以被看作是一种投资品。只不过这种留存是本国留存在别国那里，或者别国留存在本国这里。搞清楚上面这点，是正确理解有钱有货币的世界的重要前提，也是理解外汇储备、外汇占款、结汇导致的货币发行的前提。

小结

在没有钱的世界里，消费、投资和储蓄的概念和关系非常清楚。人们在一定时期里，要么消费要么投资，投资使未来有消费（存货投资），或者扩大消费（固定资产投资）。进行不能扩大未来消费的固定投资，以及积攒不会有人消费的消费品存货，虽然让本期看起来有很多产出，人们都很忙碌，耗费很多资源，但都属于无用的投资，是白忙活和浪费时间。投资带来的当期GDP只是副产品，投资的最终目的是未来消费品的增加，而不是胀大当期GDP。

上面的所有讨论，都不涉及一个日常中经常碰到的东西，那就是钱，或者说货币。有钱有货币的讨论，则会使人们的分析变得复杂，因为货币本身有流动，有沉淀，有扩张，有收缩，有自己的供需。本文旨在简单描述一个简单真实经济的状况，之后的文章会在本文的基础上，结合徐诺金老师的《优势突围》，分析纯粹的钱的情况，以及钱和物共存的现实世界。

Professor Xu Nuojin of the People's Bank of China published "Advantageous Breakthroughs" in May 2015. The book is divided into three volumes and collects observations and thoughts from Professor Xu over the past decade, particularly on the topics of consumption and investment, providing readers with valuable insights.

In a certain period (e.g., a year), people produce flows of consumer goods and investment goods. The flow of consumer goods consumed in that year is generally considered as consumption for that year, while all the flows of investment goods for that year, as well as the retained flows of consumer goods, are generally considered as investment for that year. This perspective maintains the sum of consumption and investment equal to the total flows of consumer and investment goods for that year. If savings are considered as the unconsumed portion of output, then savings naturally equal investment.

Expressing the above description in formulaic terms: People's output flow = Flow of consumer goods + Flow of investment goods. Since not all flow of consumer goods is necessarily consumed, we have: Output flow = Consumption of consumer goods + Retained flow of consumer goods + Flow of investment goods. For the three components mentioned above, people generally only consider the consumption of the flow of consumer goods as consumption. Thus, we have: Output = Consumption (consumption of flow of consumer goods) + Investment (= investment in inventory, i.e., retained flow of consumer goods + investment in fixed assets, etc.). And if output flow - consumption = savings, then clearly savings = investment.

If the consumer goods retained from the past cannot be consumed now, and the investment goods retained from the past cannot produce consumer goods anymore, such as spoiled rice and rusted machines, then how should we consider these retained consumer and investment goods? To guard against risks, people would want to hold a certain inventory of consumer goods. And to produce more consumer goods in the next year, people would need to maintain a certain inventory of investment goods. Spoiled rice reduces the inventory of consumer goods, while rusted machines decrease the inventory of investment goods. Thus, people need to work more and produce more to compensate for the reduced rice inventory and the rusted machines.

There is an absurdity here. If society desires to produce more things in a certain period, one way is to constantly destroy what was left behind or to keep damaging what was left behind. If a bridge was built last year and is not needed this year, there will be no investment goods produced this year. However, if the bridge built last year is blown up, or if the bridge collapses, and it is rebuilt this year, then there will be a new round of investment this year, seemingly resulting in more current output than if there were no bridge to build.

Compared to the absurdity of destroying and reproducing or producing for the sake of production, there is another absurdity: producing for the sake of production. People have a limited amount of things they can consume in a year, but the roads built on Earth are far from reaching their limits. The roads built this year, even if never used, contribute to this year's output goal. Also, while the things people eat are limited, there is no upper limit to the uneaten food, so people can produce a lot of food and stack it up, contributing to this year's output goal.

These two absurdities above actually reveal some of the problems at present. The Chinese people are very busy, things are always breaking and needing repairs, roads need repaving, rebuilding is frequently required for newly constructed municipal projects. What is "reassuring" is that every repetition of production creates GDP. If a house is built and doesn't need to be rebuilt for hundreds of years, won't that mean there's no new GDP? However, the problem is, if everyone is so busy, how will there be time to "go home often"?

The total capital formation in GDP includes total fixed capital formation and changes in inventories. If, for the sake of making current GDP look good, investment is blindly expanded, the result will either be a surplus of factories that won't start production and roads that no one will use (stock of fixed asset investment), or a surplus of things that can't be sold (inventory investment). The bizarre thing is that GDP doesn't measure stock. No matter how much inventory and idle capacity there is, it won't be reflected in GDP. As long as factories are continuously built and goods are stored, there will be GDP.

In the past, when both investment goods and consumer goods were scarce, building a road would mean people would use it, and things produced would always have a market. So pursuing GDP wouldn't leave behind surplus capacity and inventory. However, now, building a road doesn't necessarily mean people will use it, and producing things doesn't necessarily mean there's a market for them. Thus, pursuing GDP through expanded investment leads to the problem of overcapacity and inventory. Some might say that if something is built this year, it's built this year; next year is a new year. But at least we can see that much of the work this year is in vain, and everyone could use some rest. In a world with money and currency, there will be even more negative consequences.

However, these absurdities above don't mean that investment is unimportant. In fact, China still needs a large amount of investment to produce consumer goods to satisfy everyone's needs. This is also the point Professor Xu mentioned in "Advantageous Breakthroughs". People need education services, medical services, convenient transportation services, better accommodation services, etc., all of which require investments in education, healthcare, transportation, real estate, etc. Without investment, there won't be more consumption. Of course, this kind of investment is not the low-quality investment that needs to be constantly rebuilt, nor is it the idle capacity investment that doesn't meet the needs, and it's definitely not the inventory investment in products that no one needs. Future investment will be led by consumption, not investments made just to inflate current GDP. This is likely the true meaning of consumption becoming the engine of growth.

Expanding the connotations of consumption and investment to imports and exports in an open economy, apart from consumption and investment, we also need to consider imports and exports. If China has imports without exports in a year, it means that within China's flows of consumer goods and investment goods produced for that year, some flows of consumer goods are consumed domestically, some flows of consumer and investment goods are retained domestically, and some flows of consumer and investment goods are taken by foreign countries. In other words, the domestic output flow for that year is greater than domestic consumption and retention. If China only has imports without exports, it means that within China's flows of consumer goods and investment goods produced for that year, some flows of consumer and investment goods are consumed or retained from foreign countries. In other words, the domestic output flow for that year is less than domestic consumption and retention.

If there are both imports and exports, then the situation combines the two scenarios above. In a year, some things produced in China go to foreign countries, and some things from foreign countries come to China. This results in differences between the flows of consumer and investment goods that people in China can consume, retain, and those produced in China, i.e., the self-consumed and self-retained flows of consumer and investment goods for that year are less than the self-produced flows of consumer and investment goods for that year. Simultaneously, there is consumption and retention of foreign flows of consumer and investment goods.

So, what does a positive or negative net export mean? Let's first consider the scenario of giving and receiving for free. If China gives a lot of things to foreign countries for free in a year, even though it appears like exports, both cases mean that within that year, China's domestic output flow is greater than domestic consumption and retention. However, in the case of exports, China obtains the right to exchange for some things from foreign countries through equivalent trade, although this exchange operation is delayed until the future. But giving for free does not grant China the right to exchange for things from foreign countries in the future.

Similarly, receiving for free and imports, even though they both appear to allow China to consume flows of consumer and investment goods and retain flows of consumer and investment goods more than the self-produced flows of consumer and investment goods, in the case of receiving for free, foreign countries won't gain the right to extract Chinese consumer or investment goods in the future. In the case of imports, because when foreign countries export things to China, they gain the right to exchange for Chinese consumer or investment goods in the future, it means China might face a positive net export in the future.

Thus, we can see that current net exports are actually equivalent to retaining some output flows for now, to be consumed in the future. The only difference is that this retention is not within the borders of the exporting country but rather in foreign countries where the ability to extract foreign goods is retained. In this context, imports and exports can indeed be placed within the framework of consumption and investment. They can be seen as either future consumer goods or investment goods. The only distinction is that this retention is either in another country for one's own country, or in one's own country for another country. Understanding this point is an important premise for correctly comprehending a world with money and currency, as well as understanding foreign exchange reserves, foreign exchange deposits, and the issuance of currency caused by balance of payments.

Summary:

In a world without money, the concepts and relationships of consumption, investment, and savings are very clear. People, over a certain period, either consume or invest. Investment leads to future consumption (inventory investment) or expanded consumption (fixed asset investment). Fixed investments that can't expand future consumption and accumulating inventory of unconsumable consumer goods, though they seem to create a lot of output in the current period and keep people busy and resource-intensive, are essentially useless investments, leading to wasted effort and time. The GDP generated by investment is a byproduct; the ultimate purpose of investment is to increase future consumer goods, not inflate current GDP.

All the discussions above don't involve a common thing encountered in daily life: money or currency. Discussions involving money and currency would make analyses more complex because currency itself flows, accumulates, expands, contracts, and has its own supply and demand dynamics. This article aims to describe a simple scenario of a simple real economy. Future articles will build on this foundation, combining Professor Xu Nuojin's "Advantageous Breakthroughs," to analyze pure money scenarios as well as the coexistence of money and physical goods in the real world.