读书笔记之经济学原理(一)
Part I Introduction
Chapter 1 - Ten Principles of Economics
Economy 这个词来源于希腊语的 oikonomos , 意思是“one who manages a household”，管理一个家庭的人，TA要根据每个成员的abilities, efforts和desires来分配“who gets what”，这其实就和社会面临的decision-making是一样的性质。
Scarcity means that society has limited resources and therefore cannot produce all the goods and services people wish to have.
Economics is the study of how society manages its scarce resources.
Economists study how people make decisions, how people interact with one another, and analyze forces and trends that affect the economy as a whole.
1-1 How People Make Decisions
The behavior of an economy reflects the behavior of the individuals who make up the economy.
Principle 1: People Face Trade-offs
To get something that we like, we usually have to give up something else that we also like. Making decisions requires trading off one goal against another.
经典取舍案例1：”Guns and Butter”
花在国防上的钱越多，花在消费品（提升民生）上的钱就越少。
经典取舍案例2：A Clean Environment and A High Level of Income
国家立法要求企业减少排污→企业生产成本上升→企业利润减少 / 企业员工工资减少 / 产品&服务价格上涨
经典取舍案例3：Efficiency and Equality
- Efficiency: The society is getting the maximun benefits from its scarce resources. “the size of the economic pie”.
- Equality: Those benefits are distributed uniformly among society’s members. “how the pie is divided into slices”.
政府在制定政策时，这两个目标往往会互相矛盾。比如政府制定的 unemployment insurance 和 individual income tax（挣得越多，交税越多）就是互相矛盾的。因为它给努力工作的人的回报变少了，因此更少的人会努力工作，相对地生产出的产品和服务业就会减少，从宏观上来看是减少了Efficiency的。
Principle 2: The Cost of Something Is What You Give Up to Get It
Because people face trade-offs, making decisions requires comparing the costs and benefits of alternative courses of action.
因为人们总在面对取舍，所以做决定的过程实际上就是权衡所有可行方案的利弊得失并拿定注意的过程，只是某个行为的代价一开始可能并不是很明显。
拿上大学来说，你得到的是智力上的提升和日后更好的工作机会，但你失去的你交的学费，和你在大学期间去上班得到的报酬。
Opportunity Cost: whatever must be given up to obtain some item.
Principle 3: Rational People Think at the Margin
Rational people systematically and purposefully do the best they can to achieve their objectives, given the available opportunities. And they often make decisions by comparing marginal benefits and marginal costs.
Economists normally assume that people are rational, 但事实是人不可能完全理性。
生活中的决定大多数都不是非黑即白的，我们既不会选择看一整天电影，也不会选择不停学习24小时，我们会考虑的问题通常是“我是该多花一小时看看笔记复习一下呢，还是看一小时电影呢”，这就是在对比边际成本 （marginal cost）和边际效益（maginal benefit）。
Marginal Change: a small incremental adjustment to a plan of action.
经典案例：“为什么水那么便宜，钻石那么贵？”
人们为某种东西付钱的意愿由它的 marginal benefit 决定的，也就是 “+1” 所带来的影响，而人们已经拥有某物的数量也决定了边际效益的多少。
Principle 4: People Respond to Incentives
An incentive is something that induces a person to act.
人都是受激励驱动的，这个“激励”可以是可能得到的奖励或惩罚。Incentives 这个概念在经济学中的地位是最重要的。
最简单的例子，当苹果的价格上涨时，消费者会选择少吃点苹果，但苹果园会雇更多的工人来收获更多的苹果。这个超级简单的例子其实很好地解释了—— 价格 对消费者和生产者的影响，决定了市场经济如何分配有限的资源。
When policymakers fail to consider how their policies affect incentives, they often end up with unintended consequences.
经典案例：行车安全法强制安全带成为汽车标配
对司机来说，小心慢行 的成本并不低，因为这样会浪费他们更多的时间和精力。所以当司机在决定要多么小心开车的时候，TA其实在比较 the marginal benefit from safer driving to the marginal cost. 当小心开车的边际效益更高的时候，司机就会选择小心慢行。比如路面结冰的时候，司机们就会比平时开车开得更慢更稳。
但安全带的出现改变了司机计算 成本-效益 的方式。安全带让交通事故 less costly，因为它减少了受伤和死亡的可能性，换句话说，安全带减少了 小心慢行 所带来的效益。
与安全带法令的初衷正好相反，有了安全带之后人们反而开车更快更不小心了，交通事故反而更多了。
而对于行人，安全带的出现对他们没任何好处，因为他们会发现不但小心开车的人少了，在发生事故的时候，他们身上（相对司机）还没有任何保护。
In a classic 1975 study, economist Sam Peltzman argued that autosafety laws produce both fewer deaths per accident and more accidents. He concluded that the net result is little change in the number of driver deaths and an increase in the number of pedestrian deaths.
1-2 How People Interact
As we go about our lives, many of our decisions affect not only ourselves but other people as well.
Principle 5: Trade Can Make Everyone Better Off 交易让大家的生活更美好
Trade allows each person to specialize in the activities she does best. And by trading with others, people can buy a greater variety of goods and services at lower cost.
Principle 6: Markets Are Usually a Good Way to Organize Economic Activity
The theory behind central planning was that only the government could organize economic activity in a way that promoted economic well-being for the country as a whole. While in a market economy, the decisions of a central planner are replaced by the decisions of millions of firms and households.
计划经济 vs. 市场经济 = 政府决定经济活动 vs. 市场供求关系决定经济活动
市场经济的两大特点就是 decentralized decision making 和 self-interested decition makers ，但它却被证明可以成功地promote economic well-being.
最经典的Adam Smith观察：看不见的手 —《国富论》，1776
Participants in the economy are motivated by self-interest and that the “invisible hand” of the marketplace guides this self-interest into promoting general economic well-being.
— Adam Smith
Market prices reflect both the value of a good to society and the cost to society of making the good.
Adam的推论：当政府干涉价格的浮动，其实就在干涉供求关系，也影响了人和公司做的决定。
1 | Thoughts |
Principle 7: Governments Can Sometimes Improve Market Outcomes
既然已经有了“看不见的手”，为啥我们还需要政府？
政府需要制定法律法规，让每个人都对自己生产的东西有产权
property rights: the ability of an individual to own and exercise control over scarce resources.
“看不见的手”不是万能的，政府会权衡“公平”与“效率”决定是把整块派画的更大，还是把每块派切的更小
market failure: a situation in which a market left on its own fails to allocate resources efficiently
1-3 How the Economy as a Whole Works
We started by discussing how individuals make decisions and then looked at how people interact with one another. All these decisions and interactions together make up “the economy.”
Principle 8: A Country’s Standard of Living Depends on Its Ability to Produce Goods and Services
科学技术是第一生产力。
productivity: the quantity of goods and services produced from each unit of labor input.
政府想要提高国家整体生活水平，需要确定所有工人都受过良好的教育，拥有他们生产产品和服务的工具，并且可以接触到当前最先进的科技。