Question about surplus value

[daishi55]

I'm having a little trouble wrapping my head around the concept of surplus value. As I understand it, a worker is paid say $10/day, and this represents the value of his labor-power. He produces boots from raw leather, using tools. The worker produces 2 pairs of boots over a period of 12 hours; the capitalist sells each pair for $40. The gross profit to the capitalist is thus $70 (2*40-10). Subtracting then $20 for the raw materials and depreciation of the tools, he is left with $50, all of which is profit - but not exactly surplus value? The $10 paid to the worker allows him to eat and survive for another day and be able to have labor-power the next day, which is worth $10. But upon closer examination, the $10 is only the value of the necessary labor - the labor representing an amount of labor-power which can be sold to the capitalist for enough money to survive another day. The surplus labor is what creates the surplus value, and is the total labor time minus the necessary labor time.

Here are my questions:

1. How do you know that the necessary labor is less than 12 hours? Couldn't it be argued that, since $10 is how much the worker needs to "recharge" his labor-power, and the capitalist will only give him the $10 if he works 12 hours, that 12 hours is the necessary labor?

2. How do you know that $10 is the absolute minimum value required to reproduce his labor-power? What if he only needs $7, and saves the extra $3? Although, I suppose that would set the value of his labor-power each day at $7, since the value of a commodity (in this case labor-power) is simply the sum of the value of all the commodities required to produce it, and therefore the capitalist would only pay $7 per day?

3. I know I make more money per day than is necessary for me to survive. But, my employers must still be appropriating surplus value, otherwise they wouldn't continue to employ me. Where does the difference between my actual wages and the value of my necessary labor come from? Is it simply sacrificed by my employers from their surplus value as a way to ensure that I keep working there?

4. Am I correct in thinking that the worker doesn't actually suffer a loss, since he is paid the exact value of the labor-power constituting his necessary labor, but the problem is that this is essentially an endless cycle where the worker is kept alive, but under unpleasant conditions, and thinks he's making money but isn't because his wages are equal to the value of his necessary labor?

Sorry for the basic questions, I'm very new to Marxist economic theory.

[FSL]

1) If the necessary labor for the worker to produce as much value as he needs to survive was 12 hours, then after 12 hours of work there'd be no value left for the capitalist.
In that case, the capitalist would have never hired the worker because he'd see no profit in that.

2) When someone says that the "labor class gets as much money as needed to reproduce itself" they're talking about the current standards of living.
The average person lives in the average house, drives the average car and gets payed the average salary.
If the average person starts receiving an above average salary then the standards of living would also comply and improve. His salary would now be considered average again. If the average person received a less than average salary the standards of living would fall. His new, decreased salary would again be considered average.

It might be confusing if you think we're talking about one person. You can look at things like labor productivity per hour, average hourly wage and so on. These examples are old, Marx wrote before things like the gdp started being tracked.

3) As I explained aboved, the "necessary to survive" doesn't mean enough to buy you 2000 calories of food. It depends on the standards of your society. Say the average worker in your country is able to drive a $15000 car. Some might be able to drive a 30000 one and some might have to take the bus because they can't afford a car at all.
The working class as a whole reproduces its labor power and gets what is necessary to survive when it can ensure that the average person continues to drive a $15000 car.

4) But the worker worked longer than that and he is left unpayed for that. So in that regard he is suffering a loss.

http://www.bls.gov/news.release/empsit.t19.htm
Here it says that the average hourly earnings are about $24-24.5.
That's average, it represents the average standards of livings for the working class. The working class in the US needs an average hourly wage of $24.5 to maintain its current standard of living. This is the value of its necessary labor.


http://stats.oecd.org/Index.aspx?DataSetCode=PDB_LV
But here we see that (the average) labor productivity per hour is $57.5 in total.
So it would seem that for every hour worked, the average person is payed for 25 minutes and spends another 35 minutes working for his boss, giving him surplus value. The capitalist then takes this money, $30+, invests about 10 or 15 and keeps the rest for himself.

Without capitalists, workers could increase their hourly earnings and thus their standards of living and also increase investments. So they are suffering a pretty big loss.

[bropasaran]

I'm having a little trouble wrapping my head around the concept of surplus value.
That's ok, Marx too had trouble wrapping his head around the concept of surplus value.

I would suggest you to look at the explanation of "surplus value", that is, of exploitation, as given by original socialism and it's development- anarchism:

What is "surplus value"?
http://anarchism.pageabode.com/afaq/secC2.html#secc21