One of the most significant ideological and yet technical debates of the early twentieth century is the socialist calculation debate, which took place between Mises and Hayek as proponents of capitalism and socialists such as Lange. Our objective in this article is to examine the rise and fall of this debate by analyzing Hayek's most important work in this field, the book "Individualism and Economic Order". This discussion began with Mises, who claimed that a socialist economy and, consequently, economic planning were impossible. He reasoned that this impossibility stemmed from the inability of a planning system to calculate prices. This impossibility was interpreted by socialists like Lange as the impossibility of socialism due to the complexity of calculations or the absence of competition in a socialist system. However, Mises and later Austrian economists like Hayek argued that this impossibility was something beyond mere computational problems related to price calculation or the lack of competition. Although Hayek makes crucial points in explaining the miracle of the price mechanism and the market institution, he has overlooked important issues, and his theory has become an idealized one. While it is true that socialism is impossible due to the elimination of the market, the abstract capitalism envisioned by Hayek is also practically impossible for non-Western countries due to its abstract and ahistorical perspective.
Introduction
The debate over the "Socialist Calculation Debate" is one of the most fundamental disputes in the history of twenty century economic thought. Hayek dedicated three separate articles to this subject in his book “Individualism and Economic Order”. The context of this controversy dates back to 1920, when Mises argued that a socialist economy, due to the absence of a price system for capital goods, is incapable of rational economic calculation. In response, Oskar Lange and Abba Lerner put forward the theory of "market socialism," claiming that a planning board could determine equilibrium prices through trial and error and by simulating the market mechanism. In these three articles, while expanding and completing Mises's critique, Hayek provides a decisive and profound response to these claims — a response that goes beyond mere "impracticality" of planning and points to its epistemological impossibility

Materials and Methods
One of the most important methodological points made by Hayek is his rejection of the common narrative of the debate, which claims Mises had in mind theoretical and absolute "impossibility" while Hayek considered practical "impossibility." Hayek emphasizes that there is no separation between the theoretical and the practical: a theory that relies on unrealistic assumptions, such as perfect knowledge and a static world, is an invalid theory. From Hayek's perspective, the mathematical economics approach, with its simultaneous equations, systematically eliminates what is our main task to explain. In this collection of articles, Hayek presents his epistemological argument, which is the core of his critique of socialism. In his view, if we assume that all the knowledge necessary for planning is available to a single mind, then no economic problem exists, and the problem becomes merely technical. However, in the real world, knowledge is dispersed among millions of individuals, and a significant part of this knowledge is knowledge of particular time and place (local and tacit knowledge) that cannot be collected or centralized. A planning board can never gain access to this knowledge, regardless of its computational power. In response to Hayek, Lange proposed "managed competition," whereby a planning board could achieve equilibrium prices by experimentally setting prices, checking warehouse inventories, and adjusting prices based on surplus or shortage. Hayek argues that Lange and his supporters "contemplate a stationary world in which no further change occurs and economic history has reached its final stage." They ignore the central role of the capital market, speculators, and entrepreneurs. Hayek also offers a fundamental critique of the concept of "marginal cost" which Lange uses as a pricing criterion. He writes that "the excessive preoccupation with the hypothetical conditions of a stationary equilibrium has led modern economics... to endow the concept of costs with a definiteness and certainty which cannot be attributed to any cost phenomenon in real life." In the real world, where constant change exists, costs are not "given"; rather, they are shaped by entrepreneurs' subjective estimates of future selling prices.

Discussion and Result
In these articles, considering Lange and his supporters as his opponents, Hayek concludes that rational economic calculation under socialism is not only impractical but impossible. His main argument can be summarized in several points: The first point concerns the unrealistic nature of the "market simulation game." In a real market, investors and speculators risk their own wealth and destiny, and this is what makes them accountable to consumers. In his view, "speculating and investing cannot be played at." The second point concerns the lack of a real capital market. Lange denies the existence of a market for capital goods, but Hayek shows that without a capital market, there is no signal for intertemporal allocation of resources. The main function of the capital market is to assess which investments have been successful and which have been unsuccessful. In the absence of real prices for capital goods, the planning board "cannot know whether a particular investment is rational or not." The third point concerns the concept of competition as a discovery process. For Hayek, competition is a discovery process, not a state of equilibrium. The cost and demand curves which Lange assumes the planning board has access to do not "exist objectively in the real world and are therefore not recognizable to real actors; they must be discovered day by day." This discovery process only occurs when entrepreneurs risk their own resources and face real competition.

Conclusion
In the "Socialist Calculation" articles of Individualism and Economic Order, Hayek elevates Mises's critique of socialism from a "computational" argument to a deeper "epistemological" one. He shows that the main problem of socialism is not a lack of computational power, but our structural ignorance of the inherent dispersion of knowledge in society. No planning board, regardless of its computational ability, can obtain the dispersed knowledge that resides in the minds of millions of individuals and is transmitted through price signals in the market. Hayek's theoretical innovation in this debate is shifting the focus of attention from equilibrium to process. While Lange and neoclassical economics were focused on finding equilibrium prices (a problem that is unsolvable even in theory), Hayek showed that the real problem is "coordination" under conditions of constant change. The capital market and entrepreneurship are the institutions that make this coordination possible, and their elimination means eliminating the possibility of any rational calculation. Ultimately, this controversy remains not only as a powerful theoretical critique of socialism but also as a fundamental statement about the nature of knowledge, rationality, and social order.