Marx presented this idea back in the 1860s. He phrased it a little differently and built the idea up from the idea of exchanging commodities.
In Marx's text, he discusses the history of commodity exchange, how people usually exchanged Commodities for Money which they exchanged back into other Commodities they needed. (E.g. I'll sell you my wool for coin, which I can use to buy food.) He called this CMC exchange. (Commodity-Money-Commodity).
This gave rise to people who had hoards of money, and could invert the exchange -- Money into Commodities into Money + delta Money. He called this MCM exchange (Money-Commodity-Money), and posited that it could only exist if the second M was larger than the first -- why turn your money into commodities and back into money if you weren't going to get more money as a result? So it must be that if MCM exchange exists, then it must be MC(M+∆M). Once sufficient hoards are accumulated, they will continue to accumulate.
Marx, of course, carries on with his own opinions about what to do with this and how society should be structured. He also bases his ideas not on data like Piketty, but on building up a model of a Capitalist economy from principles.
I think it's interesting to see this line of argument presented historically and compare/contrast that with the more data driven analysis we see in Piketty. (No matter how you feel about the rest of Marx's work.)
Edit: Downvotes? I feel like I'm presenting a factual response to the parent poster. I know it contains the word 'Marx', but I'm not diving into socialism/communism elements of his work, but rather the analytical dialectic of his critique of capitalism as a system.
> why turn your money into commodities and back into money if you weren't going to get more money as a result
I'm guessing this is oversimplified, but I haven't read the book. Otherwise, the simple fact is no trade in business is guaranteed, there will be plenty of such exchanges that lose money due to speculation. At the very least your buyer could pull out or go bankrupt before finalising the sale resulting in a fire sale and a loss.
Of course, by sheer probability if not talent, some people will win more than they lose and get ahead. The real danger is the plays that an excessive force of money can enable, like predatory and monopolistic practices in buying up a market (or legislators), or driving a competitor out of business. That's where money really makes money.
Marx tended to focus on roles more than persons or transactions. Buyers and sellers, capitalists and workers, etc. Any individual might play any particular role at any given time. (For instance, I personally fill the role of worker with my day job and capitalist with my 401k.)
The reason I mention that is because his thesis was that, in aggregate, the role of capitalist must expect a positive return on MCM transactions, or they wouldn't occur. Individuals may suffer losses, but as a role it just be positive.
He's less data driven than Piketty, and he builds this notion on top of the idea that there is a desire to hold wealth. Or, put another way, it is natural in an economy of commodities and money to prefer holding money over any given commodity. Eg, having a hoard of money is more useful than having a hoard of wool, as it is generally easier to convert money into a commodity you need than to convert between two commodities.
So the natural inclination is to try and increase wealth, and MCM exists commonly, so therefore MCM must be a net engine for increasing wealth. (Even if individual cases are losses.)
I'm less confident in answering your first question. It hasn't come up in my reading, but I'm not a scholar. It could be in there. (One of the things Marx often does is open windows to look at something and then move on without diving deep on them. For instance he acknowledges inflation, and moves on rather quickly.)
No problem! Again, I'm just some internet person who happened to listen to some lectures and did some reading, so my take might be a bit off. But I find this stuff fascinating. Doubly so for something like Marx who everyone has an opinion on, but I feel very few folks have actually spent much time diving into.
In Marx's text, he discusses the history of commodity exchange, how people usually exchanged Commodities for Money which they exchanged back into other Commodities they needed. (E.g. I'll sell you my wool for coin, which I can use to buy food.) He called this CMC exchange. (Commodity-Money-Commodity).
This gave rise to people who had hoards of money, and could invert the exchange -- Money into Commodities into Money + delta Money. He called this MCM exchange (Money-Commodity-Money), and posited that it could only exist if the second M was larger than the first -- why turn your money into commodities and back into money if you weren't going to get more money as a result? So it must be that if MCM exchange exists, then it must be MC(M+∆M). Once sufficient hoards are accumulated, they will continue to accumulate.
Marx, of course, carries on with his own opinions about what to do with this and how society should be structured. He also bases his ideas not on data like Piketty, but on building up a model of a Capitalist economy from principles.
I think it's interesting to see this line of argument presented historically and compare/contrast that with the more data driven analysis we see in Piketty. (No matter how you feel about the rest of Marx's work.)
Edit: Downvotes? I feel like I'm presenting a factual response to the parent poster. I know it contains the word 'Marx', but I'm not diving into socialism/communism elements of his work, but rather the analytical dialectic of his critique of capitalism as a system.