This framework emerged during a recent conversation with a new partner, one of those discussions that begins with portfolio construction and quietly drifts into philosophy, usually without anyone quite noticing when the transition happens.
It struck me that investors tend to fall into two broad camps: the physicist and the biologist.
The physicist believes markets obey discoverable laws. With enough data, precise measurement, and the right models, outcomes should be predictable. Valuation anchors conviction. History is trusted. Mean reversion is assumed, less as a tendency, more as a scheduled event that keeps getting postponed.
The biologist sees markets differently. Investing, in his view, is a complex and adaptive system. Observation matters as much as data. Judgment complements measurement. The rules are not fixed. They evolve.
The difference becomes most visible when performance disappoints. The physicist’s confidence in models often remains intact. When results fail to materialise, the instinct is to refine definitions of value or add another layer of precision often without first asking whether the regime itself has changed.
The biologist starts with a different question: what has changed in the environment, and what might change next? Incentives shift. Correlations migrate. Liquidity behaves in ways that rarely appear in backtests. What looks mispriced may simply reflect a new reality.
This is not a rejection of quantitative analysis. It is a rejection of false precision particularly when decimals begin to outnumber degrees of freedom.
Data is used to validate observations, not to override them. Stress, fragility, crowding, reflexivity, and liquidity variables that resist clean modelling often determine outcomes.
Markets are open systems. A strategy can be right in theory and still fail in practice. Timing matters. Path dependency matters. Survival matters.
Crises, we agreed, are selection mechanisms. They expose brittle processes, punish leveraged certainty, and reward adaptability. Where the physicist often responds by adding complexity to defend a challenged framework, the biologist simplifies sometimes abruptly and waits.
That conversation also clarified why my own work looks the way it does. I focus more on building portfolios and selecting managers or strategies that can adapt as regimes shift those that respect liquidity, manage drawdowns, and prioritise survival before optimization.
In markets shaped less by laws than by adaptation, longevity is not a concession. It is the strategy.