资本主义的第二个主要原则,是界定产品价值的原则。产品的价值,是它对某个特定的人或相对于另一事物而言的重要程度。当价值是相对于某个人而言时,称为"利用价值",或简称"效用";当它与另一事物相比较时,称为"交换价值",或简称"价值"。在资本主义下,某物的效用价值是通过其边际效用来评估的。一单位产品的边际效用,是能够满足最弱需求的那一部分效用。这就是所谓的"边际效用递减"理论。根据这一理论,效用不能只从生产者的角度和生产成本来评估,因为这样只考虑了供给而没有考虑需求;也不能只从消费者的角度(效用、可欲性以及相对的可得性或稀缺性)来评估,因为这样只考虑了需求而没有考虑供给。效用价值应当同时从供给和需求两方面加以观察和评估。

The second major principle of capitalism is the principle which defines the value of the product. The value of the product is the degree of its importance, relative to a particular person or relative to another thing. When the value is used relative to a person, it is called “the value of the benefit,” or simply the “benefit.” When measured against another thing, it is called the “value of exchange” or simply the “value.” Under capitalism, the value of the benefit of a thing is evaluated by its marginal benefit. The marginal benefit of a unit is that benefit which satisfies the weakest need. This is known as “the diminishing marginal utility” theory38. According to this theory, the benefit is not evaluated from the viewpoint of the producer and the costs of production only; this would only consider supply but not demand. Nor is it evaluated from the viewpoint of the consumer alone (benefit, desirability, and relative availability or shortage); this would imply the consideration of demand without supply. The benefit value should be observed and evaluated from the viewpoint of both supply and demand.

边际效用理论认为,一件物品的效益应当在满足程度最低的那一点上加以衡量。例如,一条面包的价值应当在饥饿程度最低时来衡量,而不应在人人都饥饿、或需要面包的人极度饥饿时来衡量。换句话说,面包的效益价值是在市场上面包充足的时候测定的,而不是在面包短缺的时候测定的。正如我们稍后将看到的,边际效用递减规律并非总是成立;这很可能正是资本主义根基中缺陷和潜伏弊病的根源之一。

Marginal utility states that the benefit of a thing should be assessed at the least or minimum point of satisfaction. For example, the value of a loaf of bread should be assessed at the least point of hunger and should not be assessed when everybody is hungry or when the one who needs the bread is too hungry. In other words, the benefit value of the bread is measured at a time when bread is abundant in the market, not at a time when there is a shortage of bread. The law of diminishing marginal utility does not always hold as we shall see later; this could very well be one of the sources of defects and dormant faults in the foundation of capitalism.

交换价值是一种属性，使某物适合与其他产品进行交换。某物的交换强度是相对于另一物而衡量的。例如，小麦相对于玉米的交换价值，是通过为换取一单位小麦所需让出的玉米单位数量来估算的。

The exchange value is an attribute which makes a thing suitable for exchange with other products. The strength of exchange of a thing is measured relative to another thing. For example, the value of exchange of wheat relative to corn is estimated by the number of units of corn which should be conceded to obtain one unit of wheat.

交换发生在两种价值相同或相近的商品或服务之间。研究交换价值对经济学家而言十分必要，因为它是产品交换的基础。它是一种可以衡量的效用；它也可作为衡量商品和服务的尺度，并借此衡量行为的生产力。

Exchange occurs between two commodities or services which are similar or close in their values. The study of the exchange value is necessary for economists because it is the basis for the exchange of products. It is a utility which can be measured; it also serves as a scale with which commodities and services are measured and by which the productivity of actions can be measured.

生产被定义为为创造利益或增加某物的利益而投入的劳动。为了判断某项工作是否具有生产性,或者确定哪项工作具有更高的生产率,必须有一个准确的尺度来衡量生产率。这个尺度就是各种产品和服务的社会价值。换言之,它是对所投入劳动和所提供服务的集体评估。这种评估之所以必要,是因为在现代,为交换而生产已经占据主导地位,几乎取代了为消费而生产。在当今经济中,几乎每个人都将自己的产出与他人的产出进行交换。交换产品和服务的正当方式是通过补偿。为了估算某项产品或服务的补偿金额,需要估算交换价值。因此,对“价值”的认识和定义是生产和消费中的一个基本因素;它对于所有旨在满足需求的研究都至关重要。

Production is defined as the work invested for creating benefit or increasing benefit in a thing. In order to identify whether a work is productive or not or to determine which work has greater productivity, there must be an accurate scale by which productivity can be measured. This scale is the societal value of the various products and services. In other words, it is the collective evaluation of the work spent and the service provided. Such an evaluation is necessary because in the modern time, production for the purpose of exchange has dominated and almost replaced production for consumption. In today’s economy, virtually every person exchanges his/her production with other people’s production. The proper way of exchanging products and services is through compensation. In order to estimate the amount of compensation for a product or service, the value of exchange needs to be estimated. Hence, the knowledge and definition of the “value” is an essential factor in production and consumption; it is essential for all the studies leading to the satisfaction of the needs.

在现代历史中，这种交换价值一直由一种交换类型主导，即以货币交换产品或服务。商品或服务相对于货币的交换价值被称为“价格”。因此，价格就是一件商品或一项服务相对于货币的交换数量。交换价值与价格的区别在于：交换价值是一物与其他（任何）物之间的交换比率，而价格则是一物与货币之间的交换比率。可以想象，所有商品的价格可能同时上涨或下跌。然而，所有商品彼此之间的交换价值不可能同时上涨或下跌。商品的价格也可能发生变化，而不导致其交换价值或效益价值的改变。商品的价格只是它的诸多价值之一，即商品相对于货币的价值。自然地，价格已成为判断一物是否有益、以及界定该物益处程度的事实标准。如果社会对某种商品或服务给予高价，该商品或服务就被视为有生产力或有益的。该商品或服务的益处程度，由大多数消费者愿意支付以拥有或使用它的价格来衡量。以价格评估的产品和服务可以是任何商品或服务：农产品或工业产品；服务可以是商人或运输公司、医生或工程师的服务。

In modern history, this value of exchange has been dominated by one type of exchange, the exchange of a product or service for money. The exchange value of a commodity or a service for money is called the “price.” The price, therefore, is the amount of exchange of a commodity or a service relative to money. The difference between the value of exchange and the price is that the value of exchange is the exchange ratio of one thing related to (any) other thing, while the price is the exchange ratio of one thing related to money. It is perceivable that the prices of all goods rise or fall at the same time. It is impossible, however, for the exchange values of all commodities relative to each other to rise or fall at the same time. It is also possible for the prices of commodities to change without resulting in a change in their value of exchange or value of benefit. The price of a commodity is only one of its values; it is the value of a commodity relative to money. Naturally, the price has become the de facto scale for deciding whether a thing is beneficial or not and for defining the degree of benefit of that thing. The commodity or the service is considered productive or beneficial if the society puts a high price for this commodity or service. The degree of benefit of this commodity or service is measured by the price which the majority of the consumers agree to pay for possessing or utilizing it. Products and services evaluated by a price can be any commodity or service: agricultural or industrial product; the service is that of a trader or transportation company, doctor or engineer.

在资本主义制度下，商品的价值是相对的（虚拟的），而非绝对的。例如，一条面包的价值就是在市场上面包充足的假设下它的边际效用；这一观点基于边际效用递减的概念。当一条面包被提供给饥饿的人而面包稀缺时，面包的价值就会过高。随着需求减弱，价值逐渐下降，直至需求面包的人不再饥饿、且有足够的面包供想要购买的人获取时，价值才会稳定下来。因此，价值（即产品的效用）需要在对该产品的需求最低、供应最充足的时候进行估算。

he value of a commodity under capitalism is a relative (virtual) one and not absolute. The value of a loaf of bread, for example, is its marginal benefit assuming that the bread is abundant in the market; this is based on the diminishing marginal utility concept. When the loaf of bread is offered to one who is hungry and the bread is scarce, the value of the bread is too high. The value diminishes until it settles down when the people demanding the bread are no longer hungry and there is enough bread for those who want to acquire it. So the value (which is the benefit of the product) needs to be estimated at the time when the demand for the product is the lowest and the supply of the product is plentiful.

该产品还有另一种价值，即交换价值。交换价值是指用一条面包可以换到的商品和劳动的数量。如果为一条面包所换取的是货币，那么这种价值就成为价格。在资本主义制度下，这两种价值是分开的，并有两个截然不同的名称：效用，以及交换价值或货币。

The product also has another value, which is the exchange value. The exchange value is the quantity of commodities and efforts that could be exchanged in return for the loaf of the bread. The value becomes a price if what is obtained for the loaf of the bread is money. These two values, under capitalism, are separate, and have two distinct names, benefit and the value of exchange or money.

这一价值定义并不准确。需要注意的是，在"效用"和"价格"这两种价值观中，估价者衡量的都是相对于消费者而言的价值，这种观点并不能衡量产品本身的效益。以一条面包为例，该定义并没有涉及面包内在的效益，即面包具有满足饥饿的属性。实际上，面包的价值就是其中所包含的效益数量。在衡量这一数量时，应当考虑稀缺性因素，但稀缺性不应用来定义价值。无论该产品是通过狩猎、制造、耕种、销售还是购买而获得，价值的这一观点（即产品中所蕴含的效益数量）都成立。无论效益与人相关还是与其他事物相关，无论产品丰富还是稀缺，效益都保持不变。事实上，价值是指一种具有特定实在性的特定事物，而不是指一种随时间和状况而变化的相对事物。换言之，价值应当是对效益的客观衡量，而非相对衡量。

This definition of value is inaccurate. Note that in both views of the value (benefit and the price), the estimator is measuring the value relative to the consumer. This view does not provide any measure of the benefit of the product itself. In case of the loaf of bread, the definition of value does not refer to the inherent benefit in the bread in the sense that bread has a property of satisfying the hunger. In reality, the value of the bread is the quantity of benefit in it. When this quantity is measured, the element of scarcity should be taken into consideration, but it should not define the value. This view of the value (quantity of benefit embedded in the product) holds whether the product is possessed through hunting, manufacturing, farming, selling, or buying. The benefit remains the same whether this was related to the person or related to another thing, whether the product is plentiful or scarce. Indeed, value is a name for a specific thing which has a specific reality; it is not a name for a relative thing, which varies over time and from one condition to another. In other words, the value should be an objective measurement of benefit and not a relative one.