I just read the article you linked. It's full of utter nonsense; it is not serious economics. One example: it talks at length about how there are different forms of value, namely individual value (which any normal economist would call production cost), and social value (the actual amount the commodity sells for). It then goes on to say, "there are two basic forces that govern the way individual values become social values" [emphasis mine]: (A) average productivity, and (B) interaction of supply and demand. The first is described mostly correctly. When describing the second, the article says, "We only learn how much labor society has put into widget making when we enter the market and compare the products of our labor with the rest of society." Okay, but that is not the only thing we learn from the market price. We also learn whether the society needs our commodity at all. Since the article talks about "social value" it almost implies that our commodity will always have some value to the society (it's called "social" after all), but that is often not the case at all.
But here is where the article is most clearly wrong:
> But most important to the MudPie theory, demand doesn’t create the social value of a commodity. It only helps determine if labor has been apportioned to the right tasks. Labor is creating the value
First, the article is contradicting itself. It reduces everything to "labor is creating the value" -- if that were the case, why mention "governing" force (B) above at all? Also note, which value are we now talking about? Individual or social? (I assume the latter). Second, it conveniently presents the MudPie argument as "belief that demand is creating value". No, that is not what the MudPie argument says at all. It is the recognition of demand (which is an intellectual process) that is creating value, and that value can be (although not always is) wholly separate from the labor cost (or the "individual value").
Consider the following example. I buy a used or antique piece of furniture from someone who used to own it and who now believes the piece is quite useless since it is old. In addition, the owner does not mind selling me the piece at a low price since he had got out from the 20 years of using it all the "value" he believed he could get out of it. On inspecting the piece, I determine that the piece was made by a known designer. I resell the piece for ten times the amount I paid for it, and for three times its retail purchase price when it was new. Where is the labor here (ignoring transportation cost)? The answer is that the "labor" here is in me recognizing the potential value of the piece either from the appearance or through matching the label through a catalog (about 5 minutes of work). Now exactly the same process will occur when a reseller of a commodity finds a more profitable way to sell it. The reseller is creating value.
TL;DR There is also intellectual labor involved after the item is made but before it is sold, ignored by Marx entirely and purposefully.
> Since the article talks about "social value" it almost implies that our commodity will always have some value to the society (it's called "social" after all), but that is often not the case at all.
Seriously? Again? My goodness. Listen, we have already established you are the kind of person that goes around pretending to discredit an entire branch of economics without having the slightest clue about what that branch even claims to say. Fine. But repeating the same nonsense after being told that it is nonsense is just too much. The entire freaking idea revolves around how individual labor which under capitalism is done by private initiative is converted to social labor, which is through market mechanics accepted as socially necessary. Of course that whether or not that labor was in fact desired, has some value for society, is a factor, and that is a fundamental aspect of the LTV. The Wikipedia article explains this, the article I linked to explains it, I explained earlier that value under the LTV is realized at the point of sale, ie, when someone actually goes through and establishes the usefulness of the labor invested by exchanging something (usually money) for it.
The rest of your post conflates price with value, which are different things according to Marxian thought, so again it is pretty useless as far as "debunking Marx" goes. Again, this is even explained in the Wikipedia article you linked to but that obviously haven't read.
Now, do you want to believe the LTV and everything Marx wrote is wrong without having any actual idea of what that is? That's cool. Just don't try to have a conversation with someone that has bothered to read it and think you can get away with it.
But here is where the article is most clearly wrong:
> But most important to the MudPie theory, demand doesn’t create the social value of a commodity. It only helps determine if labor has been apportioned to the right tasks. Labor is creating the value
First, the article is contradicting itself. It reduces everything to "labor is creating the value" -- if that were the case, why mention "governing" force (B) above at all? Also note, which value are we now talking about? Individual or social? (I assume the latter). Second, it conveniently presents the MudPie argument as "belief that demand is creating value". No, that is not what the MudPie argument says at all. It is the recognition of demand (which is an intellectual process) that is creating value, and that value can be (although not always is) wholly separate from the labor cost (or the "individual value").
Consider the following example. I buy a used or antique piece of furniture from someone who used to own it and who now believes the piece is quite useless since it is old. In addition, the owner does not mind selling me the piece at a low price since he had got out from the 20 years of using it all the "value" he believed he could get out of it. On inspecting the piece, I determine that the piece was made by a known designer. I resell the piece for ten times the amount I paid for it, and for three times its retail purchase price when it was new. Where is the labor here (ignoring transportation cost)? The answer is that the "labor" here is in me recognizing the potential value of the piece either from the appearance or through matching the label through a catalog (about 5 minutes of work). Now exactly the same process will occur when a reseller of a commodity finds a more profitable way to sell it. The reseller is creating value.
TL;DR There is also intellectual labor involved after the item is made but before it is sold, ignored by Marx entirely and purposefully.