Definition
adam-smith distinguishes two related but distinct prices for every commodity:
Natural price: The price that exactly covers the natural (ordinary) rates of wages, profit, and rent required to bring the commodity to market. It is the long-run cost of production.
Market price: The actual price at which the commodity sells at any given moment, determined by the intersection of current supply and effectual demand.
“The natural price, therefore, is, as it were, the central price, to which the prices of all commodities are continually gravitating.”
The Three Components of Natural Price
Every commodity’s natural price resolves into three parts, corresponding to the three factors of production:
- Wages — the ordinary payment to labour
- Profit — the ordinary return on the capital (stock) advanced
- Rent — the ordinary payment to the landlord for use of the land
In a primitive economy with no private property in land or accumulated capital, the labourer takes the whole produce. Once land is enclosed and capital accumulates, all three claims exist.
The Gravitational Mechanism
Market price oscillates around natural price through the mechanism of supply and effectual demand:
When market price > natural price: Profits are above ordinary rates. Suppliers are attracted; workers and capital flow toward this industry. Supply increases until market price falls back to natural price.
When market price < natural price: Profits are below ordinary rates. Suppliers withdraw; workers and capital shift to other industries. Supply falls until market price rises back to natural price.
Effectual demand: Not total demand, but the demand from buyers willing to pay the full natural price. This is the relevant quantity for the gravitational mechanism.
Exceptions: When Market Price Stays Above Natural Price
In normal competitive markets, the gravitation mechanism works. But in certain cases, market prices can remain above natural price indefinitely:
- Natural monopolies: Unique conditions (a particular vineyard for fine wine, a unique mineral spring) cannot be replicated, so supply cannot expand
- Legal monopolies: Government grants exclusive privileges, preventing competitive entry
- Trade secrets: Proprietary processes kept secret for the proprietor’s lifetime
- Guild/apprenticeship restrictions: Legal limits on entry into trades prevent supply from expanding
In all these cases, Smith notes, the monopolist’s gain comes at the public’s expense — the price of monopoly is the highest which can be got, while the price of free competition is the lowest which can be taken for any sustained period.
Modern Equivalents
Long-Run Competitive Equilibrium
In modern microeconomics, natural price corresponds to long-run competitive equilibrium: the price at which economic profit is zero (i.e., all factors earn their opportunity cost). Entry and exit drive markets toward this point.
Market Price as Signal
The divergence of market price from natural price is the signal the market sends to allocate resources. High market prices (above natural price) signal “produce more here.” Low market prices (below natural price) signal “produce less.” This is the invisible-hand operating through price signals.
Connections
invisible-hand
The gravitational pull of market price toward natural price is the invisible hand at the level of individual markets. It requires no central planner — profit signals coordinate the movement of capital and labour automatically.
labour-theory-of-value
Natural price is grounded in the labour theory of value: it is the price that covers the labour (wages), capital (profit), and land (rent) required to produce the commodity. Long-run price reflects cost of production.
nudge-theory
Where market prices are systematically distorted (by monopoly, externalities, or cognitive biases), the gravitational mechanism fails and policy intervention may be warranted. This is the analytical foundation for Thaler’s nudge framework.
mental-models
Munger explicitly includes “supply and demand” and “incentives” as foundational mental models. Natural price vs. market price is the formal version of supply-demand reasoning — understanding that price divergences are temporary and self-correcting in competitive markets.
prospect-theory
Kahneman’s prospect theory documents cases where buyers and sellers respond to prices in non-rational ways (anchoring, loss aversion, framing). These are the mechanisms by which individual market prices diverge systematically from what rational supply-demand analysis would predict.