ERGODİK OLMAYAN DÜNYADA EVRİM: REPLİKATÖR DİNAMİĞİ VE POST-KEYNESYEN BELİRSİZLİK

Abstract

Ekonomik ve sosyal stratejilerin evrimini inceleyen standart evrimsel oyun modelleri, genellikle örtük bir ergodiklik varsayımına dayanır: yani oyunun yapısının/rejiminin (ödeme matrisinin) zamanla sabit kaldığı ve geçmiş verilerin geleceği öngörmekte güvenilir olduğu kabul edilir. Post-Keynesyen iktisat ise ekonomik dünyanın non-ergodik (yapısal olarak değişken ve öngörülemez) olduğunu, dolayısıyla radikal belirsizlik altında rasyonel optimizasyonun geçersizleştiğini savunur. Bu çalışma, söz konusu paradigmal boşluğu doldurmak üzere, değişen çevresel koşullar altında stratejilerin evrimini analiz eden iki seviyeli bir meta-evrimsel model geliştirmektedir. Modelde, strateji paylarının evrimi replikatör dinamiği ile tanımlanırken, oyunun çevresi Poisson süreciyle rassal yapısal kırılmalara uğramaktadır. Popülasyonda iki strateji rekabet halindedir: (i) mevcut durumu yüksek maliyetle öğrenip optimum tepki vermeye çalışan optimize edici ajanlar ve (ii) çevresel değişimleri dikkate almadan düşük maliyetli ve yeterli düzeyde karar kuralını uygulayan sezgisel ajanlar. Analitik çözümlemeler ve ajan-tabanlı simülasyonlar göstermektedir ki, istikrarlı (ergodik-benzeri) bir çevrede yüksek getiri potansiyeli sayesinde optimize edici strateji baskın çıkarken, sık yapısal kırılmaların yaşandığı non-ergodik bir dünyada evrimsel süreç sezgisel stratejiyi seçmektedir. Bu bulgu, radikal belirsizlik altında konvansiyonlar ve hayvani güdü gibi kavramların, rasyonel optimizasyona kıyasla daha dayanıklı evrimsel mekanizmalar olarak ortaya çıktığını göstererek literatüre kuramsal bir katkı sunmaktadır.

Keywords

• Evrimsel Oyun Teorisi
• Replikator Dinamiği
• İktisat Teorisi

EVOLUTION IN A NON-ERGODIC WORLD: REPLICATOR DYNAMICS AND POST-KEYNESIAN UNCERTAINTY

Abstract

Standard evolutionary game models that examine the evolution of economic and social strategies typically rely on an implicit assumption of ergodicity: the structure or regime of the game (the payoff matrix) is assumed to remain stable over time, and past data are presumed to provide reliable guidance for the future. Post-Keynesian economics, however, argues that the economic world is fundamentally non-ergodic—structurally changing and inherently unpredictable—thereby rendering rational optimization invalid under radical uncertainty. To bridge this paradigmatic gap, this study develops a two-level meta-evolutionary model that analyzes the evolution of strategies under shifting environmental conditions. In the model, the evolution of strategy shares is governed by replicator dynamics, while the game environment undergoes random structural breaks modeled by a Poisson process. Two strategies compete within the population: (i) optimizing agents who attempt to learn the current state at high cost and respond optimally, and (ii) heuristic agents who employ a low-cost but sufficiently effective decision rule that disregards environmental changes. Analytical results and agent-based simulations show that while the optimizing strategy dominates in a stable (ergodic-like) environment due to its high return potential, evolutionary dynamics select the heuristic strategy in a non-ergodic world characterized by frequent structural breaks. This finding provides a theoretical contribution to the literature by demonstrating that, under radical uncertainty, conventions and animal spirits emerge as evolutionarily more resilient mechanisms compared to rational optimization.

Keywords

• Evolutionary Game Theory
• Replicator Dynamics
• Economic Theory.

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