Abstract: Natural necessity is the kind of necessity that is supplied by ‘nature’: e.g., necessarily, a glass is broken when it is pressed with a certain force. Relevant topics of natural necessity include causation, dispositions, laws of nature, and counterfactuals. Those subjects are vital for a proper ontological characterization of various entities of scientific inquiry. They are also intimately connected to some scientifically important epistemic notions such as observation, hypothesis, explanation, and prediction. In the field of formal ontology, different notions of natural necessity have been investigated individually to a differing degree and the close interrelationship between them has been little explored. This paper provides an introductory panoramic study of natural necessity in formal ontology to help ontologists utilize it in their actual practice. As for ontology of natural necessity, fundamental commitments to type-level causation, type-level dispositions, and laws of nature are especially discussed. As for its epistemology, close consideration is given to the link between natural necessity and scientific explanation. The practicality of ontology of natural necessity is also illustrated with a case study of suitable primary choices of natural necessity for upper and domain ontologies and its potential application to some domain-specific tasks.
Keywords: Natural necessity, causation, disposition, law of nature, counterfactual