 Consider, for example, a tornado. At any moment, a tornado depends for its existence on dust and debris, and ultimately on whatever micro-entities compose it; and its properties and behaviors likewise depend, one way or another, on the properties and interacting behaviors of its fundamental components. Yet the tornado’s identity does not depend on any specific composing micro-entity or configuration, and its features and behaviors appear to differ in kind from those of its most basic constituents, as is reflected in the fact that one can have a rather good understanding of how tornadoes work while being entirely ignorant of particle physics. The point generalizes to more complex and longer-lived entities, including plants and animals, economies and ecologies, and myriad other individuals and systems studied in the special sciences: such entities appear to depend in various important respects on their components, while nonetheless belonging to distinctive taxonomies and exhibiting autonomous properties and behaviors, as reflected in their governing special science laws. (The point might be generalized yet further to include human artifacts which are not the object of any natural science, but whose conditions of individuation are tied to human language and practice. But artifacts are set aside in this entry, as these raise distinctive issues that are discussed in the entry on  material constitution.  Whether there are composites that are neither artifactual nor amenable to scientific analysis is controversial, and if there are, they plausibly will not meet candidate autonomy conditions on emergence. But this will not be explored further here.)