springtian’s log

在 Mankiw 的博客上看到 Peter Singer 的一片文章，标题为 The Hidden Costs of Money （金钱的隐性成本）。作者在文章中从 Karl Marx 的《1844年经济学哲学手稿》谈到 2006年 Vohs 等人在《科学》杂志上发表的研究报告 The Psychological Consequences of Money，希望让读者了解和思考的就是金钱在人与社会间关系中起到的作用。

现代社会的发展使得金钱的作用越来越强大且突出，人们在思考问题和解决问题的时候，首先考虑金钱的倾向性也愈加明显，年轻一代将如何看待金钱在社会中的位置，将决定着我们人类 humanity 的未来。

我们希望人类不再为没有足够的金钱来购买生存必需品而烦恼，但也不希望金钱无孔不入并主宰一切。

English version of the article: The Hidden Costs of Money

中文翻译版: 金钱的隐性成本

Summary of Chapter 14 - Firms in competitive Markets

关键词：

competitive market: 完全竞争市场
average revenue (AR): 平均收入
marginal revenue (MR): 边际收入
marginal cost (MC): 边际成本
total revenue (TR): 总收入
total cost (TC): 总成本
average total cost (ATC): 平均成本
variable cost (VC): 变动成本
average variable cost (AVC): 平均变动成本
sunk cost: 沉没成本

A competitive market has three characteristics:

• There are many sellers and many buyers in the market.
• The goods offered by the various sellers are largely the same so that each buyer and seller is a price taker.
• Firms can freely enter or exit the market.

For a competitive firm, the firm’s price (P) equals both its average revenue (AR) and its marginal revenue (MR). There are three general rules for profit maximization in competitive markets:

• If MR > MC, the firm should increase its output.
• If MR < MC, the firm should decrease its output.
• At the profit-maximizing level of output, MR = MC.

As a firm’s MC curve determines the quantity of the goods the firm is willing to supply at any price, MC curve is also the competitive firm’s supply curve.

A shutdown refers to a short-run decision not to produce anything during a specific period of time because of current market conditions.

Firm’s short-run decision: shut down if TR < VC or P < AVC.
The competitive firm’s short-run supply curve is the portion of its MC curve that lies above AVC.

Exit refers to a long-run decision to leave the market.

Firm’s long-run decision: exit if TR < TC or P < ATC.
The competitive firm’s long-run supply curve is the portion of its MC curve that lies above ATC.

爱心果汁, originally uploaded by Appleping.

好久没有在 flickr 上闲逛了。偶然间发现这个女生拍摄的照片好清新，顿时闷热的夏天多了丝凉意。

Summary of Chapter 13 - The Cost of the Production

关键词：

total revenue: 总收益
total cost: 总成本
profit: 利润
explicit costs: 显性成本
implicit costs: 隐形成本
economic profit: 经济利润
accounting profit: 会计利润
production function: 生产函数
total-cost curve: 总成本曲线
marginal product: 边际产量
diminishing marginal product: 边际产量递减
fixed costs: 固定成本
variable costs: 变动成本
average total cost (ATC): 平均总成本
average fixed cost (AFC): 平均固定成本
average variable cost (AVC): 平均变动成本
marginal cost (MC): 边际成本
economies of scale: 规模经济
diseconomies of scale: 规模不经济
constant returns to scale: 规模收益不变

Profit is a firm’s total revenue minus its total cost.

When economists speak of a firm’s cost of production, they include implicit costs as well as explicit costs. Implicit costs require an outlay of money by the firm while explicit costs do not.

The distinction between explicit and implicit costs highlights an important difference between how economists and accountants analyze a business. An economist measures a firm’s economic profit as the firm’s total revenue minus all the opportunity costs (explicit and implicit) of producing the goods and services sold. An accountant measures the firm’s accounting profit as the firm’s total revenue minus only the firm’s explicit costs.

Economic profit is an important concept because it is what motivates the firms that supply goods and services.

The relationship between quantity of inputs used to make a good and the quantity of output of that good is called production function, which could be illustrated by a total-cost curve. The marginal product of any input in the production process is the increase in the quantity of output obtained from one additional unit of that input. The property whereby the marginal product of an input declines as the quantity of the input increases is called diminishing marginal product.

Total cost can be divided into two types: fixed costs and variable costs. Variable costs vary with the quantity of output produced while fixed costs do not. Average total cost tells us the cost of a typical unit of output if total cost is divided evenly over all the units produced. Marginal cost tells us the increase in total cost that arise from producing an additional unit of output.

The graph of average and marginal cost shows four curves: average total cost (ATC), average fixed cost (AFC), average variable cost (AVC) and marginal cost (MC). Typical cost curves share three properties:

1. Marginal cost eventually rises with the quantity of output.
2. The ATC curve is U-shaped.
3. The MC curve crosses the ATC at the minimum of ATC.

Short-run and long-run costs are related. The long-run ATC curve is much flatter U-shaped than the short-run ATC curve. All short-run curves lie on or above the long-run curve. When long-run ATC declines as output increases, there are said to be economies of scale. When long-run ATC rises as output increases, there are said to be diseconomies of scale. When long-run ATC does not vary with the level of output, there are said to be constant returns of scale.

Summary of Chapter 12 - The Design of the Tax System

关键词：

deadweight loss: 无谓损失
legal tax avoidance: 合法避税
illegal tax evasion: 逃税
marginal tax rate: 边际税率
average tax rate: 平均税率
lump-sum tax: 定额税
vertical equity: 纵向公平
horizontal equity: 横向公平
proportional tax: 比例税
regressive tax: 累退税
progressive tax: 累进税
tax incidence: 赋税归属

In designing a tax system, policymakers have two objectives: efficiency and equity.

One tax system is more efficient than another if it raises the same amount of revenue at a smaller cost to taxpayers.

1. The most obvious cost is the tax payment itself.
2. The deadweight losses that result when taxes distort the decisions that people make. The deadweight loss is the inefficiency that a tax creates as people allocate resources according to the tax incentive rather than the true costs and benefits of the goods and services that they buy and sell.
3. The administrative burdens that taxpayers bear as they comply with the tax laws. The burden includes not only the resources cost in tax process, but also the behavior of legal tax avoidance and resources devoted to complying with the tax laws. The administrative burden could be reduced by simplifying the the tax laws. Yet simplification is always politically complicated.

Everyone agrees that the tax system should be equitable, but there is much disagreement about what equity means and how the equity of a tax system can be judged.

1. When discussing the efficiency and equity of income taxes, economists distinguish among three notions of the tax rate: the average tax rate, the marginal tax rate and the lump-sum tax.
2. The benefits principle: people should pay taxes based on the benefits they receive from government services.
3. The ability-to-pay principle: taxes should be levied on a person according to how well that person can shoulder the burden. This principle leads to two corollary notions of equity: vertical equity and horizontal equity.
   • Vertical equity states that taxpayers with greater ability to pay taxes should contribute a larger amount. There are three systems, differing in how quickly taxes rises with income: proportional, regressive and progressive.
   • Horizontal equity states that taxpayers with similar abilities to pay taxes should pay the same amount.

Tax incidence–the study of who bears the burden of taxes–is central to evaluating tax equity.

Summary of Chapter 11 - Public Goods and Common Resources

关键词：

excludability: 排他性
rivalry in comsumption: 消耗中的对抗性
private goods: 私用物品
public goods: 公共品
common resource: 公用资源
free rider: 搭便车的人

Because public goods are not excludable, the free-rider problem prevents the private market from supplying them. The government, however, can potentially remedy the problem. If the government decides that the total benefits of a public good exceed its costs, it can provide the public good, pay for it with tax revenue, and make everyone better off.

When one person uses a common resource, he or she diminishes other people’s enjoyment of it. Because of this negative externality, common resources tend to be used excessively. The government can solve the problem by reducing use of the common resources through regulation or taxes. Alternatively, the government can sometimes turn the common resouces into private goods.