Subjective Value, Price Signals & Why Central Planning Always Fails

Value is subjective. That single sentence, when you really absorb it, dissolves most of the case for central planning. A bottle of water is worth more to a man in the desert than to a man at a fountain, and there is no objective measure that reconciles the two. Value is not a property of the object; it is a relationship between an object and a valuing mind, and minds differ.

Because value is subjective, it cannot be summed. There is no social welfare function that adds up everyone's preferences into a single number that a planner can maximize, because preferences are not comparable across people and are not even stable within a person over time. The attempt to compute 'what society wants' is not just hard; it is a category error. Society does not have a want. Individuals have wants, and they trade.

The price system is what makes this workable. A price is not a measure of value; it is a signal of relative scarcity, formed by the marginal exchanges of people who each know only their own situation. When copper becomes scarce somewhere, no one has to notify a central office. The price rises, and thousands of people — miners, recyclers, engineers, consumers — each adjust their behavior based on that one number, without coordinating and without knowing why it moved. The information has been compressed into a signal that requires no one to understand the whole.

This is the miracle Hayek described in 'The Use of Knowledge in Society,' and it remains the most underappreciated achievement of market economies. The marvel is not that markets produce goods; it is that they coordinate the actions of millions of strangers who share no goal, no language, and no plan, using nothing but a set of changing numbers.

Central planning fails not because planners are stupid — many were brilliant — but because the inputs they need do not exist in a form they can use. They can observe quantities, but quantities without prices tell them nothing about what people actually want, because want is subjective and only revealed in the act of paying. A warehouse full of goods that no one would choose to buy is not wealth; it is waste, and only the price system distinguishes the two.

The modern temptation is to believe that big data fixes this — that with enough information, we can finally plan. But big data observes past choices; it does not discover the valuations that would have been made under conditions that did not exist. And it still cannot compare subjective preferences across people. More data about the wrong thing does not solve the problem; it makes the illusion of a solution more convincing.

The practical humility here is worth carrying into any decision-making role. You cannot know what people value by asking them in the abstract; you can only observe what they do when it costs them something. Design your systems — a product, a team, an economy — to let those revealed preferences surface and to respond to them, rather than to impose your theory of what people ought to want. The price signal, humble as it is, is the closest thing we have to a truth-telling mechanism about what actually matters to actual people.