[claudiawerner]

>If the value is what offer and demand agree on, exploitation disappears, in Marx's theoretical model.

This is not true; Marx's model of exploitation (known to modern economists as the Profit-Exploitation Correspondence Model (PECP)) does not concern itself with what demand and offer agree on within a labor negotiation. Marx says that workers do not sell their labor, they sell their labor-time (e.g. X units of time/goods) during which they exercise their labor-power. The discrepancy between the value of the time and the value produced during that time is where this 'exploitation' comes in.

The idea that exploitation is a matter of opinion or agreement adds a moral or justicial spin to what Marx considered to be a fact of the capitalist economy. Whether the people involved are happy with the situation or agree to it does not change this discrepancy of value or its representation in money.

[mejutoco]

Thanks, that is a clear explanation.

> The discrepancy between the value of the time and the value produced

I am thinking how can one value this time. If it is valued by the market (how much someone is willing to pay for it) we would end up with the same problem, no?

It must be intrinsically valued, I am assuming.

[thiagoharry]

No, what people will pay for the product in a market it's the price. Marx talks about the "value", which is different than price. The price is equal the value only in very limited and simplified models. Offer and demand will change the price, but not the value, for example.

What is the "value"? Well, the prices cannot be explained only in terms of offer and demand (a society with an offer of 100 pens and demand for 100 pens and offer of 100 planes and demand for 100 planes still would not sell pens and planes for the same price) nor entirely because of the price of raw materials (because this only postpones the explanation: from where came the price of the raw materials?). It also cannot be explained only based on subjectivity, because there exists a number, which is a very objective measure, representing the price if you balance offer, demand, assume competition and discard several perturbations. The "value" tries to explain this basis value that later will became the price and show objectively and numerically how the wealth is produced and distributed.

This "value" is measured by Marx as the quantity of labor socially necessary to produce the product. Given a car, the value represented by a car can be measured by the mean time necessary for the workers to produce that car in the industry plus the value transferred by the machines and tools used by those workers (whose value came from the workers that produced these machines and tools). Both manual and intellectual work need to be taken into account and you can also assume that some complex tasks or more intense work can produce more value than simple tasks in the same time.

Given this, you can compare the value produced by a worker with the value of the things that the worker can buy with its salary. This is how Marx measures these things and shows the exploitation in the society.

[dontlaugh]

Value produced can be measured as the price of commodities sold. Thus there is a clear difference between the cumulative price of commodities a worker produces in an hour and the amount they are paid for that hour. The difference is appropriated by the owner of the means of production (the capitalist) as profit.

The capitalist wants to pay as little as possible per hour, but will on average long term not be able to pay less than the cost of living. Capitalists pay just enough so that workers as a class reproduce themselves (so there are more workers), but less than the value the workers produce.

[dontlaugh]

Correct, Marx talks about exploitation the same, whether of wood or labour power.

Marxism is explicitly amoral, it does not concern itself with that is morally right. It is a social science that analyses the contradictions within the material world and their consequences.