A stratigraphic survey of economic thought.
1980 — present
The uppermost stratum contains the unconsolidated sediments of living discourse: behavioral economics, complexity theory, digital-native monetary systems, and the post-2008 reckoning with systemic fragility. These ideas have not yet been compressed by time into the hard certainties of deeper layers. They remain loose, shifting, contested.
Modern economic thought wrestles with the contradictions inherited from every layer below: the tension between individual rationality and collective emergence, between equilibrium models and chaotic systems, between the mathematical elegance of general equilibrium and the stubborn messiness of actual markets populated by actual humans.
"The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design."
— F. A. Hayek, The Fatal Conceit, 1988
Behavioral economics, catalyzed by Kahneman and Tversky's prospect theory, dismantled the fiction of homo economicus and revealed the systematic biases that govern real decision-making. The field continues to expand, absorbing insights from neuroscience, evolutionary psychology, and information theory.
Behavioral turn: 1979 (Kahneman & Tversky)
Global Financial Crisis reshapes macro consensus, 2008
Rise of complexity economics and agent-based modeling
1936 — 1980
The Keynesian stratum represents a thick deposit of interventionist thought, laid down in the aftermath of the Great Depression and compacted by decades of policy application. John Maynard Keynes overturned the classical presumption that markets naturally clear, introducing the possibility of persistent involuntary unemployment and the paradox of thrift.
"The ideas of economists and political philosophers, both when they are right and when they are wrong, are more powerful than is commonly understood. Indeed, the world is ruled by little else."
— John Maynard Keynes, The General Theory, 1936
The Keynesian consensus produced the postwar managed economies: fiscal policy as macroeconomic stabilizer, the welfare state as automatic stabilizer, and the implicit social contract between capital, labor, and government. This stratum is thick and well-cemented, its institutions still load-bearing even where the intellectual formation has been partially eroded by monetarist and new-classical critique.
The IS-LM model, Hicks's formalization of Keynes, became the standard pedagogical framework. Phillips curve relationships suggested a stable trade-off between inflation and unemployment. The Bretton Woods system anchored international monetary order. Each of these would fracture under the stagflation pressures of the 1970s, creating the fault lines visible at the boundary above.
Keynes's General Theory published 1936
Bretton Woods system: 1944–1971
Phillips Curve: A. W. Phillips, 1958
Stagflation crisis signals stratum boundary
— unconformity: 1870–1936 —
1870 — 1936
The marginalist revolution deposited a new kind of economic sediment: mathematically precise, individually focused, equilibrium-seeking. Jevons, Menger, and Walras independently discovered the principle of marginal utility, replacing the classical labor theory of value with a subjective theory rooted in the incremental satisfaction derived from the last unit consumed.
Alfred Marshall synthesized these insights into the neoclassical framework that dominated the discipline for half a century. Supply and demand curves, partial equilibrium analysis, the notion of a self-correcting market mechanism — these became the sedimentary bedrock of economics departments worldwide, compacted into textbooks that would persist long after the intellectual climate shifted.
"The theory of value must be based on a study of utility and not of labour. The value of labour itself must be determined by the value of the produce, not the value of the produce by that of labour."
— W. Stanley Jevons, The Theory of Political Economy, 1871
Leon Walras pursued the most ambitious formalization: general equilibrium theory, proving (under stringent assumptions) that all markets could simultaneously clear. This mathematical stratum, while elegant, would prove brittle — unable to accommodate the persistent disequilibria that Keynes would later document. Yet its crystalline structure survives as the deep grammar of modern microeconomics.
Marginalist revolution: 1871–1874
Marshall's Principles: 1890
Walrasian general equilibrium formalized
1776 — 1870
The classical stratum is dense, well-consolidated, and heavily fossiliferous. Adam Smith, David Ricardo, Thomas Malthus, John Stuart Mill, and Karl Marx laid down the thick deposits of political economy that would become the bedrock upon which all subsequent schools would build or rebel against.
Smith's insight into the division of labor and the coordinating power of markets established the foundational grammar. Ricardo formalized trade theory through comparative advantage and developed the labor theory of value to its most rigorous expression. Malthus introduced population dynamics as a geological force — slow, implacable, and capable of overwhelming any surface improvement.
"It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest."
— Adam Smith, The Wealth of Nations, 1776
Marx, working from within the classical tradition while simultaneously detonating it, produced the most seismically active deposit in this stratum. His analysis of surplus value, capital accumulation, and the tendency of the rate of profit to fall introduced fault lines that would propagate upward through every subsequent layer of economic thought.
"Capital is dead labour, that, vampire-like, only lives by sucking living labour, and lives the more, the more labour it sucks."
— Karl Marx, Capital, Volume I, 1867
Smith: Wealth of Nations, 1776
Ricardo: comparative advantage, 1817
Malthus: population principle, 1798
Marx: Das Kapital, Vol. I, 1867
1500 — 1776
The mercantilist stratum is dark and compressed, its organic content transformed under centuries of pressure into dense economic doctrine. Before economics existed as a discipline, there was the practical statecraft of wealth accumulation: bullionism, trade balances, colonial extraction, and the equation of national power with gold reserves.
The Physiocrats — Quesnay, Turgot — represented the first systematic attempt to model the economy as a circular flow, their Tableau Économique functioning as an early input-output model. Agriculture alone was considered truly productive; all other activity merely transformed existing value.
"The wealth of a country does not consist in its gold and silver only, but in its lands, houses, and consumable goods of all kinds."
— John Locke, Some Considerations, 1692
This stratum's compression under the weight of classical revolution above has made much of its content difficult to read in its original form. What survives is the recognition that economic thought did not spring fully formed from Smith's brow — it accumulated, layer by layer, from centuries of practical observation about trade, money, and the sources of national prosperity.
Bullionism: 16th–17th century
Quesnay: Tableau, 1758
Petty, Locke, Hume: proto-economics
antiquity — 1500
The deepest stratum. Metamorphic basement rock, transformed beyond easy recognition but forming the absolute foundation upon which everything above rests. Aristotle's distinction between oikonomia (household management) and chrematistics (money-making) established the moral boundary that would haunt economic thought for two millennia.
The Scholastic philosophers — Aquinas foremost among them — debated the just price and the morality of usury, embedding economic reasoning within theological frameworks that modern economics would labor to escape. Ibn Khaldun, writing in the 14th century, articulated cyclical theories of economic rise and decline that anticipated much later Western formulations.
"The life of money-making is one undertaken under compulsion, and wealth is evidently not the good we are seeking; for it is merely useful and for the sake of something else."
— Aristotle, Nicomachean Ethics, c. 340 BCE
At this depth, the boundary between economic thought and philosophy, theology, and political theory dissolves entirely. The bedrock is not economics at all — it is the question of what constitutes the good life and how communities should organize the material conditions of existence. Every stratum above is, in some sense, a partial and increasingly specialized answer to this metamorphic basement question.
Aristotle: oikonomia, c. 340 BCE
Aquinas: just price theory, 13th c.
Ibn Khaldun: Muqaddimah, 1377
Below this point: undifferentiated basement rock. The questions that precede all economics.