CONCEPT
Historical Contingency
The evolutionary principle — pressed by Mayr against triumphalist accounts of cosmic progress — that the specific outcomes of life's history depend on unrepeatable sequences of accidents that no physical law alone predicts.
In 1989, Stephen Jay Gould published Wonderful Life, organized around a thought experiment: if the tape of life could be rewound to the Cambrian explosion and replayed from identical starting conditions, would the same forms emerge? Would vertebrates appear? Would intelligence arise? Gould's answer was no. Ernst Mayr, though he disagreed with Gould on much else, agreed on this — and grounded the argument more radically, in population-level processes rather than mass extinctions. Every population faces a unique combination of selection pressures, genetic variation, geographic circumstance, and random drift. The outcomes are not random, but they are specific to the conditions, and the conditions are never repeated. Multiply this specificity across billions of years and millions of lineages, and the result is a biosphere that could not have been predicted from first principles.
In The You On AI Field Guide
Mayr reinforced the position with an empirical observation carrying philosophical force. Out of the perhaps fifty billion species that have existed