This article was originally published on forbes.com.

Bitcoin's exchange rate is famously volatile. Just two weeks ago, one bitcoin was worth $42,577. For the past few days it has ranged between $50,000 and $52,000. The movements in bitcoin’s price are dizzying – and can even confuse people, or cause them to think of bitcoin as a speculative asset good for little more than trading for short term gain.

Even if one accepts that digital assets are an exciting new technology, why would one bitcoin command such a high price? It isn’t issued by a government, and it isn’t pegged to a preexisting asset like gold.

Value is a tricky thing. It’s so tricky that economists have pondered it for centuries and developed many competing theories as to how a market good obtains, and maintains, value.

The theory that best explains the price of bitcoin (and all market goods) is offered by the Austrian school, which developed the subjective theory of value.

The subjective theory asserts that the value of a market good is determined by individual actors in the market who perceive it as valuable. Individual minds are black boxes – even if we ask people why the behave a certain way, they will have varying ability to explain their thoughts and motivations. And even if we dive deep into one particular individual’s reasoning as to why they value one market good over another, we will have only learned the motivation of a single market actor – of which there are billions.

At first, the subjective theory might be misunderstood as a tautology – market goods are worth what people will pay for them. But, it feels circular because it is. Market price is the only measure of value that is knowable, because it’s the only one that is real.

While it may be unsatisfying, at least the subjective theory of value isn’t obviously wrong, and that’s saying a lot. Other theories of value that came before, such as the classical theory of value outlined by Adam Smith, and leading, perhaps ironically, to the Marxian theories of labor and power, presupposes the existence of value as a separate, measurable property that is only approximated by price. However, this leaves out the power of consumers to influence prices based on their individual circumstances.

Another model is the intrinsic theory of value. According to monetary theory, market goods have an intrinsic value tied to their ability to be used for something other than money. Salt, which has been used as money, has intrinsic value deriving from its usefulness as seasoning. Gold is used in industrial processes and jewelry, and so it is said to have intrinsic value.

The intrinsic theory of value falls apart as soon as you look at the money in your wallet, and realize that green paper rectangles have no utility beyond their usefulness as money, and yet somehow, cash is king. Intrinsic value cannot explain the value of all market goods, and because of that, it is incomplete at best, and useless at worst if you want a way to explain why bitcoin, or dollars, are traded every day for goods and services.

Bitcoin can be viewed as a tangible market good that lays the argument about theories of value to rest. Bitcoin is software that has only one utility: to function as money. It is traded globally and its supply is uninfluenced by politics or other factors.

It is reasonable to look at the fundamentals of bitcoin, the growth in its adoption, and the ecosystem developing around it to make educated guesses about how much bitcoin’s price will change over time. However, to learn what bitcoin is actually worth, today, look no further than the price. The price is all you can know about how today’s market values a global monetary network that offers final settlement every 10 minutes.

Bitcoin is actually worth what people will trade for it. Its meteoric rise from being worth $0 to $50,000 in 14 short years tells us something useful about people’s preferences – and how they view this transformative technology.