According to Aristotelian essentialism, the nature of an organism is constituted of a particular goal-directed disposition to produce an organism typical of its kind. This paper argues—against the prevailing orthodoxy—that essentialism of this sort is indispensable to evolutionary biology. The most powerful anti-essentialist arguments purport to show that the natures of organisms play no explanatory role in modern synthesis biology. I argue that recent evolutionary developmental biology provides compelling evidence to the contrary. Developmental biology shows that one must appeal to (...) the capacities of organisms to explain what makes adaptive evolution adaptive. Moreover, the specific capacities in question are precisely those that, according to Aristotle, constitute the nature of an organism. Essentialism 1.1 Aristotelian biological kinds Evolutionary anti-essentialism 2.1 Taxonomic anti-essentialism 2.2 Explanatory anti-essentialism Adaptation 3.1 Stability 3.2 Mutability 3.3 Phenotypic plasticity and adaptive evolution The natures of organisms Conclusion. (shrink)

The paper offers an account of luck, fate, and fortune. It begins by showing that extant accounts of luck are deficient because they do not identify the genus of which luck is a species. That genus of properties, the tychic, alert an agent to occasions on which the external world cooperates with or frustrates their goal-achievement. An agent’s sphere of competence is the set of goals that it is possible for them to reliably achieve. Luck concerns occasions on which there (...) is a mismatch between attempt and result; in bad luck the external world thwarts goal-achievement within the agent’s sphere of competence, in good luck the external world assists goal-achievement beyond the agent’s sphere of competence. Fateful events are those where, more passively, the agent finds the external world achieving or frustrating their goals. Fortune concerns the contraction and expansion of the agent’s sphere of competence. Eight reasons are given for accepting the account; its theoretical virtues and various things it explains. Lastly, three objections are answered; that the tychic properties relate to well-being rather than agency, that there are alternative theories of fortune available in the contemporary literature, that the account draws arbitrary distinctions between synonyms. (shrink)