（本文应发表于2015年上半年的万门公众号，现已遗失）

上海财经大学老一辈的教授郭家麟在其为马歇尔的《货币、信用与商业》所撰的序言当中提到：“在马歇尔所处的时代，西方经济学者对一般经济理论大都按一件商品或一个企业单位加以分析，今属微观经济学，而对货币价值、投资、储蓄、国民收入等则进行总体分析，今属宏观经济学。因此，写经济理论的书不讲货币及有关问题，而写货币一类的书又不涉及具体商品或个别企业的分析。”

在讨论货币的这一“宏观经济学”传统中，约翰•罗（John Law）算是有名的老资格的一位，不但在1705年留下了《论货币和贸易》这本薄薄的著作（《国富论》要到1776年出版），还在法国搞了发行纸币的试验，当上了法国的财政大臣，最终导致投机狂潮和货币崩溃，造就了法国重农学派的兴起，也据说造就了法国人至今对金融投资敬而远之的民族特点。

《论货币和贸易》是一本非常前卫的著作。罗的主张和今天的货币体系几无二致，即一部分保证金可以支持几倍于保证金金额的信用，从而使得货币量得以不受金属货币量的控制。纸币的地位一直有争议，到19世纪还有很多人认为只有实物货币才能充当货币，只有真实的或者足值（即面值等于其含金量）的货币才能作为流通手段和支付手段，亦即纸币只能被以纸的价值来流通而决不可能是表面写的数。

但贵金属矿产的分布十分不均匀，而贵金属从本国流出会导致通货紧缩，从而引发物价下降、工资减少、商业萧条等问题，因此在不为人意志为转移的贵金属开采速度面前，各国在短期里能做的，只有抢夺贵金属或者限制进口，而这引发了各种问题。

在现代，央行直接盯住物价稳定，通过调整基础货币的价格和数量，进而调节整个社会购买力，以控制价格。物价降低时，央行可以通过降低利率和增加基础货币的办法，诱使企业家和消费者增加信贷，从而增加当期的投资和消费。

如果诱使失败，央行可以任性地直接买入资产，让企业家和消费者感到自己资产升值了，从而增加当期的投资和消费。如果企业家和消费者在资产升值的时候第一要务是归还现有债务，或者干脆按兵不动等待更多上涨，导致投资和消费没有在当期增加，央行可以借钱给国家，让国家替企业家和消费者进行投资和消费，拉动经济。

但在约翰•罗的时代，现有货币量满足着社会现有的需要，更多的放贷和消费需要更多的货币，资产价值（特别是土地）提高也需要更多货币，君主花钱更需要货币，但货币量是确定的，因此面对萧条，人们受到货币的掣肘，回旋余地不多。

约翰•罗通过引入纸币的方法，将金属和纸币连接起来，纸币的发行量只要不超过一定限度，即使比金属的价值要多，甚至发生了金属流失，只要没有大规模的金属赎回，发行人就不会倒闭，纸币就能继续流通。而且，纸币的发行量只要控制得当，随经济活动相应变化，纸币的购买力也可以很稳定。这其实就是现在的金融体系，只不过纸币的角色被存款甚至余额宝份额代替。

中国央行控制的招数也变得蛮多，从控制基础货币（纸币和准备金存款），到窗口指导新增信贷总量（也就是通过信贷而增加的货币量）等方式，来控制一定时期内货币的使用量（当期把贷款创造的存款花出去这一动作），以及从当时起货币的可使用量（存款持有者可以用来花的存款总额）。

物价有上涨势头就及时紧缩以及放出紧缩信号，提醒大家冷静收手。物价有下跌势头时就及时放松，诱使大家活跃起来。

可惜约翰•罗生不逢时，他的超前构想虽然被脑动奇开的法国人采用，但很快采用就变为滥用。约翰•罗创立的通用银行（后改名为皇家银行）收购了好几家特许公司，经营各种业务，利润丰厚，股价大涨，罗也当上了财政大臣（看来这个时候央行的独立性完全不存在。

甚至连央行这个词都没有），但股价大涨就使得很多股民进入爆炒，无论是大贵族股民还是小资产者股民，都对财政大臣产生了股票只许涨不许跌的压力（老股民都知道这在上世纪九十年代意味着什么），罗只得增发纸币，使得股价不断上涨。

但纸币不是只能在赌场中使用的筹码，大量纸币从股市流向实物商品，引发通货膨胀。但作为纸币发行的准备金的贵金属还是那么多，于是挤兑和通胀让法国人抛弃了纸币，回到了硬币，罗也就身败名裂了。

长期里，物价稳定对政府和民众都好，但短期里，政府和民众希望有更多钱可以花，也希望自己持有的资产价格不断上涨。但当金融资产通过购买转化为对实物商品的需求的时候，实物商品的价格会变化，金融资产的购买力会下降。

所有的财富还原成一串数字，甚至会引发金融危机，而这不是步调一致同进同退的方阵阅兵式，而是夺路而逃你踩我踏的外滩式悲剧，一些人全身而退，脚下是无数人倾家荡产。

通过介绍日常见到的金融产品，给大家展现它们各自的特点和影响因素。让每一位消费者都能够了解认识到真正的、有益的金融逻辑，应该是：把钱，从资源冗余效率低下的地方搬去资源稀缺效率高的地方。

从而在总量不变的情况下，获得更多的产出。而金融业在中间，核心是做好风控、平衡好资负、做出合理的资金定价。

Professor Guo Jialin, a senior professor at Shanghai University of Finance and Economics, mentioned in his preface to Alfred Marshall's "Money, Credit and Commerce": "During Marshall's time, Western economists mostly analyzed general economic theories based on individual commodities or business units, falling under microeconomics. On the other hand, they conducted comprehensive analyses of monetary value, investment, savings, national income, and more, falling under macroeconomics. Therefore, writing books on economic theory did not address currency and related issues, while writing books on currency did not involve specific commodity or individual business analysis."

Within this macroeconomic tradition of discussing currency, John Law stands out as a well-known and experienced figure. In 1705, he left behind the work "Money and Trade" (while "The Wealth of Nations" was not published until 1776). He also conducted experiments with paper currency issuance in France and became the country's finance minister. This ultimately led to speculation frenzy and currency collapse, paving the way for the rise of the French Physiocrats and the enduring national characteristic of cautiousness toward financial investments.

"Money and Trade" is a highly forward-thinking work. Law's ideas align closely with today's monetary systems: a fraction of the required margin can support multiple times the credit, enabling the quantity of money to be independent of the quantity of metallic currency. The status of paper currency has long been debated. Even in the 19th century, many believed that only physical currency could serve as money, with only genuine or fully-backed (i.e., face value equals its metal value) currency acting as a medium of exchange and means of payment—meaning paper currency could only circulate based on its paper value rather than its nominal value.

However, the distribution of precious metal resources is uneven. The outflow of precious metals from a country leads to deflation, causing problems like price reduction, wage decrease, and economic recession. Faced with limited options for rapidly increasing precious metal mining rates, countries were forced to seize precious metals or restrict imports, triggering various issues.

In the modern world, central banks directly monitor price stability, adjusting the price and quantity of the base currency to regulate overall societal purchasing power, thereby controlling prices. When prices rise, central banks can reduce interest rates and increase the base currency to encourage entrepreneurs and consumers to take on more credit, boosting current investments and consumption.

If this encouragement fails, central banks can whimsically buy assets, making entrepreneurs and consumers feel that their assets have appreciated, thereby increasing current investments and consumption. If, when asset appreciation occurs, entrepreneurs and consumers prioritize repaying existing debts or waiting for further increases, leading to stagnant investment and consumption, central banks can lend money to the government, allowing the government to invest and stimulate the economy on behalf of entrepreneurs and consumers.

However, during John Law's time, the existing money supply met current societal needs. Additional lending and consumption required more money, and even increasing asset values (especially land) necessitated more currency. But the money supply was fixed, constraining people during economic downturns, leaving little room for maneuver.

John Law introduced paper currency, connecting metals and paper. As long as the issuance of paper currency did not exceed a certain limit, even if its value exceeded that of metal, or even if metal was lost, as long as massive metal redemption did not occur, the issuer would not collapse, and paper currency would continue to circulate. Moreover, as long as the issuance of paper currency was controlled properly and changed in response to economic activity, its purchasing power could remain stable. This is essentially the modern financial system, with the role of paper currency replaced by deposits and even platforms like Yu'EBao.

The playbook used by China's central bank has also diversified, from controlling base currency (currency and reserve deposits), to guiding total new credit volume through windows (i.e., the amount of money created through credit) to control the current volume of currency in use (the act of spending the deposits created by loans). Additionally, the central bank can adjust its tactics promptly in response to inflation and signal tightening, reminding everyone to be prudent. Similarly, when deflation sets in, the central bank can loosen its approach to stimulate activity.

Unfortunately, John Law was ahead of his time. While his visionary concepts were initially adopted by the adventurous French, they were quickly abused. The Banque Générale (later renamed the Royal Bank) established by John Law acquired several charter companies, engaging in various business operations that generated hefty profits and caused stock prices to soar. Law himself became the finance minister (during this period, central bank independence didn't even exist). Pressure arose on the finance minister to ensure that stock prices only went up and never down, leading Law to increase the issuance of paper currency, causing stock prices to continuously rise.

However, paper currency isn't merely a chip used in gambling. A large influx of paper currency flowed from the stock market to tangible goods, resulting in inflation. But with the limited quantity of precious metals serving as reserves for paper currency issuance, no matter how much paper currency was in circulation, even if its value exceeded that of metals, or even if a loss of metals occurred, as long as mass metal redemption didn't occur, the issuer wouldn't collapse, and paper currency would continue to circulate. And if properly controlled, the issuance of paper currency could be adjusted according to economic activity changes, maintaining the stability of its purchasing power. This is essentially the modern financial system, with the role of paper currency replaced by deposits and even platforms like Yu'EBao.

China's central bank playbook has also diversified, from controlling the base currency (currency and reserve deposits) to guiding the total volume of new credit through windows (i.e., the amount of money created through credit) to control the current volume of currency in use (the act of spending the deposits created by loans). Additionally, the central bank can adjust its tactics promptly in response to inflation and signal tightening, reminding everyone to be prudent. Similarly, when deflation sets in, the central bank can loosen its approach to stimulate activity.

But the important thing to remember is that, ultimately, all wealth is reduced to a series of numbers. And this shift isn't like a regimented parade, but more like a chaotic escape—people stepping on each other's toes as they flee. Some escape unscathed, while beneath them, countless others suffer financial ruin.

By introducing commonly encountered financial products and showcasing their characteristics and influencing factors, we aim to help every consumer understand and recognize true and beneficial financial logic: moving money from places with resource redundancy and low efficiency to places with resource scarcity and high efficiency. This way, within a fixed quantity, you can gain more output. In this financial sector, the core is to manage risk well, balance assets and liabilities, and set reasonable fund pricing.