Properties of Good Money¶
Not all objects can function effectively as money. Throughout history, a natural selection process has eliminated inferior forms of money while elevating those with superior characteristics. The essential properties that determine whether an object can serve as sound money were first articulated by the ancient Greek philosopher Aristotle around 350 BC, and his framework remains foundational to understanding money today -- including digital currencies like Bitcoin.
Aristotle's Framework¶
Aristotle left an indelible mark on the field of economics with his groundbreaking ideas about money and property. His insights, though formulated over two thousand years ago, have had a lasting influence on economic and social thought, shaping the discourse well into the Middle Ages and beyond. Aristotle's understanding of money was genius, as he identified the core qualities that a substance must possess to function effectively as a medium of exchange. These qualities -- durability, divisibility, portability, and intrinsic value (scarcity) -- remain the cornerstones of our modern conception of money.
In addition to these four core qualities, Aristotle also understood money as something that ought to be fungible -- that is, each unit should be identical to every other unit. Furthermore, he saw money as a unit of account, providing a common measure for pricing goods and services. By establishing these principles over two millennia ago, Aristotle created a framework that can be used to evaluate any proposed form of money, from ancient coins to modern cryptocurrencies.
The Five Properties¶
1. Durability¶
Durability measures money's ability to withstand time and use without deterioration. Aristotle reasoned that for a substance to serve as a reliable means of exchange, it must be able to withstand the test of time. Money should be durable, resistant to wear and tear, and not prone to decay or degradation. This quality ensures that money can be used and circulated over extended periods without losing its value or functionality.
Aristotle's emphasis on durability laid the foundation for the use of precious metals, particularly gold and silver, as the preferred form of money for much of human history. Gold exemplifies this property -- it neither corrodes, tarnishes, nor decays. The ancient Chinese recognized this principle as well when they chose bronze for their early coins, noting that bronze has a higher tensile strength and greater hardness than either of its principal components (copper and tin), enabling bronze coins to be more durable than coins made from either metal alone. In contrast, perishable commodities like cattle or grain fail as durable stores of value because they decay over time.
2. Divisibility¶
Divisibility refers to money's capacity to split into smaller denominations without losing proportional value. Aristotle understood that a viable form of money should be readily divisible, enabling people to conduct both large and small exchanges with ease. This insight paved the way for the development of standardized units of currency, such as coins and bills, which could be broken down into smaller denominations.
This property enables transactions of varying sizes and allows for the precise pricing of goods and services. Coins can be subdivided or minted in different weights. Bitcoin achieves extreme divisibility through satoshis -- each bitcoin can be divided into 100 million satoshis, enabling transactions of virtually any size. Indivisible items like diamonds fail this requirement because they cannot be split into smaller units while maintaining proportional value.
3. Portability¶
Portability describes the ease of transporting money relative to its value. Aristotle recognized that a form of money that was too bulky, heavy, or cumbersome would hinder trade and commerce, as people would be reluctant to use it for everyday transactions. For money to function as an effective medium of exchange, it must be convenient to carry and transfer.
Aristotle's emphasis on portability anticipated the evolution of money from physical commodities to more abstract forms, such as paper currency and, eventually, digital currencies. Gold concentrates significant purchasing power in small, transportable units. Large, heavy commodities like stone wheels or iron bars prove impractical for everyday exchange. Bitcoin represents the ultimate expression of portability -- billions of dollars in value can be transmitted anywhere in the world via the internet in minutes.
4. Recognizability¶
Recognizability means money must be easily and reliably authenticated. Users must distinguish genuine money from counterfeits without specialized expertise. This property is closely related to Aristotle's concept of fungibility -- the idea that each unit of money should be identical to every other unit. Fungibility ensures that money is interchangeable and that no single unit is considered more valuable or desirable than another.
The ancient Lydians, who minted the first official currency under King Alyattes around 600 BC, understood this principle well. They developed standardized coins with consistent weight and appearance, bearing the seal of the Lydian king. The sameness engineered into each coin -- a quality known as fungibility -- was crucial to establishing trust in the currency. Standardized coins with consistent weight and purity serve the recognition function, while complex verification requirements undermine money's utility as a medium of exchange.
5. Scarcity¶
Scarcity is perhaps the most critical property. Aristotle believed that representations of money should be difficult to obtain and resistant to counterfeiting. Consequently, he held that money should be made from an inherently valuable substance, such as precious metals, rather than deriving its worth solely from social convention or government decree.
This constraint preserves money's function as a store of value. Natural scarcity protects gold -- it requires sophisticated metallurgical knowledge, labor-intensive processes, and access to scarce raw materials to produce. Programmatic scarcity protects Bitcoin, where the total supply is capped at 21 million units and the rate of new creation is mathematically determined. Fiat currency fails catastrophically in this dimension due to unlimited government printing. The history of paper money, from its first introduction in Song Dynasty China around 960 AD to modern central banking, demonstrates the persistent temptation to debase currency through overissuance.
Unit of Account¶
Beyond the five core properties, Aristotle recognized money's essential role as a unit of account -- providing a common measure for pricing goods and services. By serving as a standard of value, money enables people to compare the relative worth of different commodities and make informed economic decisions. This function reduces the friction and uncertainty associated with barter systems, where the "double coincidence of wants" makes transactions cumbersome and restricts the scope of trade.
Money as a unit of account highlighted its function as a tool for facilitating commerce. This understanding of money as a means of quantifying and comparing value has been fundamental to the development of modern economic systems and the functioning of markets.
Comparative Analysis¶
Different forms of money throughout history have scored variably across these dimensions. Gold excels in all five properties, explaining its millennia-long dominance as the preferred form of money. The intrinsic value of gold cannot be overlooked -- it requires significant resources to mine and refine, giving it natural scarcity that government decree cannot replicate.
Fiat currency succeeds in portability, divisibility, and recognizability but fails critically in scarcity. The ability to print money on demand is always susceptible to the human desire to have more wealth, and history from Song Dynasty China through modern central banking shows that governments invariably yield to this temptation, printing money as they see fit while simultaneously trying to combat the inevitable consequences of inflation and devaluation.
Bitcoin represents an attempt to match or exceed gold across all five properties using cryptographic technology. It achieves durability through distributed redundancy across thousands of nodes, divisibility through satoshis, portability through digital transmission, recognizability through cryptographic verification, and scarcity through its fixed supply cap. In this sense, Bitcoin is the thoughtful and intentional result of decades of research applying Aristotle's ancient framework to the digital age.
The interplay of these properties determines which forms of money survive market competition and which disappear. Poor money drives out good money in circulation (Gresham's Law), but sound money ultimately prevails as a store of value. Aristotle's framework, articulated over two thousand years ago, remains the definitive lens through which to evaluate any monetary system.