CONCEPT
Biogenetic Law
Haeckel's 1874 formula — ontogeny recapitulates phylogeny — that development of the individual retraces in compressed form the evolutionary history of the species. Overstated in its original form; partially vindicated in its weakened modern version.
Haeckel advanced the biogenetic law in Anthropogenie (1874) with the confidence characteristic of his most provocative work. The human embryo, he argued, passes through stages corresponding to ancestral forms: fish-like with gill slits, amphibian, reptile, before arriving at its mammalian configuration. Three hundred million years of vertebrate evolution, compressed into nine months, replayed in the womb. The strong form was an overstatement, and Haeckel's embryological illustrations were censured for selective inaccuracy—he drew embryos more similar than the evidence warranted. The law was abandoned in its strong form within a generation. But a weakened version—that development builds on ancestral foundations, that later stages often depend on earlier stages—has survived every attempt to bury it. A 2012 American Naturalist paper demonstrated the recapitulatory tendency even in digital organisms evolved inside computers. Applied to AI, the framework suggests machine intelligence is recapitulating, in compressed form, the cognitive evolutionary sequence biology took hundreds of millions of years to produce.
