Economic theory is built on the flawed premise of a rational, economically-motivated individual. Financial historian Russell Napier argues this ignores psychology, sociology, and politics, making financial history a better guide for investors. The theory's mathematical edifice crumbles without this core assumption.

Related Insights

Voltaire believed outcomes are shaped by flawed, human-built institutions, not perfect systems. This philosophy directly challenges the Efficient Market Hypothesis (EMH), which assumes a rational, self-correcting market, suggesting instead that markets are shaped by human and institutional biases.

Economics can be viewed as the physics of information, where profit is the surplus created when intelligent agents organize chaos into useful order (reduce entropy) faster than the system naturally decays back into disorder.

Post-mortems of bad investments reveal the cause is never a calculation error but always a psychological bias or emotional trap. Sequoia catalogs ~40 of these, including failing to separate the emotional 'thrill of the chase' from the clinical, objective assessment required for sound decision-making.

Nobel laureate Robert Solow critiques modern macroeconomic models (DSGE) for being overly abstract and failing to represent an economy with diverse actors and conflicting interests. By modeling a single representative agent, he argues, the field has detached itself from solving real-world economic problems.

Post-WWII, economists pursued mathematical rigor by modeling human behavior as perfectly rational (i.e., 'maximizing'). This was a convenient simplification for building models, not an accurate depiction of how people actually make decisions, which are often messy and imperfect.

Financial history rhymes because the underlying driver—human nature—is constant. Core desires for wealth, recognition, and love, along with the fear of pain and envy of others' success, have remained unchanged for millennia. These emotions will continue to fuel bubbles and crashes, regardless of new technologies or financial instruments.

Contrary to popular belief, economists don't assume perfect rationality because they think people are flawless calculators. It's a simplifying assumption that makes models mathematically tractable. The goal is often to establish a theoretical benchmark, not to accurately describe psychological reality.

Milton Friedman's 'as if' defense of rational models—that people act 'as if' they are experts—is flawed. Predicting the behavior of an average golfer by modeling Tiger Woods is bound to fail. Models must account for the behavior of regular people, not just theoretical, hyper-rational experts.

Quoting G.K. Chesterton, Antti Ilmanen highlights that markets are "nearly reasonable, but not quite." This creates a trap for purely logical investors, as the market's perceived precision is obvious, but its underlying randomness is hidden. This underscores the need for deep humility when forecasting financial markets.

Despite emotional rhetoric, human behavior is fundamentally driven by incentives. Even the most ardent socialists will act as capitalists when presented with direct personal gain, revealing that incentive-based economics is a core part of human nature.