Money in Star Trek

Rick Webb constructs money in Star Trek. Not "Federation credits", which can be explained simply as a plot device, but honest-to-god money.

Although Webb posits that there's more than enough for everyone, he believes the Federation carefully accounts for every citizen's consumption.

The amount of welfare benefits available to all citizens is in excess of the needs of the citizens. Therefore, money is irrelevant to the lives of the citizenry, whether it exists or not. Resources are still accounted for and allocated in some manner, presumably by the amount of energy required to produce them (say Joules). And they are indeed credited to and debited from each citizen’s “account.” However, the average citizen doesn’t even notice it, though the government does, and again, it is not measured in currency units — definitely not Federation Credits. . . . This massive accounting is done by the Federation government in the background.

But why would the Federation do such a thing? It makes zero sense to account for something that's not scarce. We account for scarce things, like the social product of others, because it's important to use every little bit wisely. But Webb assumes that there are excess welfare benefits: under ordinary circumstances everyone can use as much energy (or whatever) as they want. So why account for it in detail.

Webb continues,

So, behind the scenes there is a massive internal accounting and calculation going on — the economics still happen. They just aren’t based on a currency unit, and people don’t acquire things based upon a currency value. People just acquire things from replicators, from restaurants such as Sisko’s or coffee shops like Cosimo’s, or, presumably, get larger things from dealerships or (more likely) factories. This could still be called “buying,” as a throwback.

This activity is buying. And if you keep accounts, your unit of account is currency by definition, even if that unit represents a physical quantity. Webb sees the contradiction, but doesn't resolve it:

It is tempting to argue here that the massive accounting system uses a unit called the Federation Credit, but i don’t believe that’s the case. If it were, the credit would be too much like money because a) accounting is done in it, b) it is issued by a governing body (like a fiat currency) and c) it is fungible, i.e. you can already buy things with it and if you could buy things with it AND a and b were true, it would pretty much be a currency. This would fly in the face of Roddenberry’s absolute diktat that the Federation has no currency.

It doesn't matter whether we call it Federation Credits, if we're accounting in it, it's money. Even if the money in some sense represents energy, it's still money. Accounting is done in it. It's a fiat unit issued by the government, i.e. each citizen's welfare benefit. Citizens can "buy" things with it: when they use energy, Webb assumes their account is drawn down. Furthermore, Webb assumes that this money is an incentive, that people will do "menial jobs that cannot be done in an automated manner ... [because] there is some small, incremental increase in your hypothetical maximum consumption, thus appealing to the subconscious in some primal way." This is money. Currency. Moolah. Cash.

Whatever we call it, Webb posits something that works exactly like money in a market economy, except for one crucial feature: Webb's money does not ration consumption. Webb thinks the Federation is doing all the work of managing a currency for literally nothing but some sort of subconscious appeal. It makes absolutely no sense. Just accounting for everything doesn't mean the "economics still happen." For the economics to actually happen, there has to be people optimizing the use of scarce resources. The citizens of even a proto-post scarcity society do not, under ordinary circumstances, optimize the use of scarce resources, so there's no economics.