 As in earlier organicism, patterns and form emerge from ongoing interaction, within and among multiple levels of organization, on multiple time-scales. But unlike the organicists, Oyama has an established theoretical alternative to contend with. Much of her argument is negative, rejecting the gene/environment dichotomy, primacy of genes as causes, and lingering preformationism of the idea of a genetic program for development. Her theoretical perspective aims to overcome entrenched (and often unrecognized) dichotomies in biological thought. Although criticized for their complexity, apparent incompatibility with scientific generalization, and lack of connection to experimental practices, Oyama’s ideas about developmental systems have been influential in twenty-first-century philosophy of biology.