A economia capitalista como sistema complexo: evolução de preços do trigo e emergência de estrutura fractal do mercado

Abstract

The study of the economy as a complex system requires considering the effects of influences on decisions made by economic agents. These decisions impact aggregate performance and the propagation of disturbances, which in turn depend on the organization of the system. Recursive interactive processes can lead to the formation of networks with fractal characteristics, exhibiting similarities and details at different scales. There is the emergence of groups with correlations (synchronization) that enable, for example, specialization on the supply side and collective behaviors in demand. Temporal series of aggregated variables within the system exhibit memory effects and nonlinearities due to the propagation of feedback chain events. These characteristics are incompatible with equilibrium-based analyses. This doctoral thesis aimed to evaluate whether capitalist economics can be considered a complex system and, if so, how this perspective contributes to our understanding of the market. The study discussed complex systems concepts and tools and applied them to economics. By analyzing the price series of wheat dating back to 1264 using Fourier transform spectrum and Hurst exponent techniques, signatures of complex systems were identified starting from the late 19th century, with a long transition that intensified with the Industrial Revolution. The analysis of contemporary capitalism reveals distinctions between periods of economic order and transitions between orders. During orderly periods, characterized by established institutions and market structures, multifractality emerges. In the short term, there is persistence with a tendency to reinforce variations, while in the long term anti-persistence prevails, with systemic crises and abrupt reversals. Intermittency occurs, with relatively stable periods alternating with high volatility. During order transitions, the long term behaves similarly to the short term. This behavior likely results from institutional ruptures and the loss of connections, which amplify uncertainty and hinder the adoption of longer decision-making horizons. Historical surveys have contributed to associating these findings with the evolution of the wheat market and understanding the underlying processes. Schematic diagrams were developed to illustrate the emergence of the market’s fractal structure across different spatial scales (local, regional, national, and global) and along the production chain. Finally, the economy as a complex system was discussed theoretically considering the diversity of agents, types of relationships, mutual influences, mechanisms of self-organization and self-organized criticality. The effects of increasing incomes, innovations and i associated with cumulative circularities that impose out-of-equilibrium dynamics and qualitative changes were highlighted.