The utility one thing that depends on its natural qualities and appears on their use or consumption, it makes it a use value. Intended for whom forging it to meet the needs or conveniences of other individuals, the producer delivery to the person that is useful, to whom you want to use, in exchange for another object and by this Act transforms in merchandise. The variable proportion in which goods of different species are changed each other, constitutes its exchange value. This leads us to determine the real substance of the value. To better understand this concept consider the relationship of change between two goods: an equal to fifty pounds of salt simple porcelain lamp.
This is to say that in these two different objects, lamp and salt, we need something in common. This something can not be a natural goods property, since its natural qualities are not taken into account, but as soon as they give them a tool that converts them to use values. In your change and this is what characterizes the relationship of change – is not taken into account their respective utility and is only considered if it they are respectively in adequate amount. As use values, goods are, first and foremost, of different quality, but as values change, can only be different in quantity. If, dispenses with the natural properties of the value of the goods using only left them a quality: the be the work products. In this sense, put that in a bed, a House, a lump of salt, we must make do without the respective utility of such objects, its particular useful way, we do not have to worry about special productive work of the Carpenter, bricklayer, of the mining, which have given them that particular form. Thus abstracting its own physiognomy of these works, we can only his common character and from that moment all are reduced to an expenditure of human labour force, i.e., to wear on the body of the man, if related to the particular way in which that force has been spent.