The paper "Temporal Ontology and Temporal Reference" by Marc Moens and Mark Steedman explores the semantics of temporal categories in language and their use in defining temporal relations between events. The authors propose an ontology based on notions like causation and consequence, rather than purely temporal primitives. A central concept is the "nucleus," which is an elementary event-complex comprising a goal event (culmination), a preparatory process, and a consequent state. Natural language categories such as aspects, futurates, adverbials, and *when*-clauses are argued to change the temporal/aspectual category of propositions under the control of this nucleic knowledge representation structure. The authors argue that the meaning of *when* is not primarily temporal but reflects its role in establishing a temporal focus, related to Reichenbach's reference time. The diversity of temporal relations conveyed in linguistic expressions arises from the nature of this referent and the organization of events and states in episodic memory under a "contingency" relation, distinct from causality. The paper also discusses the temporal/aspectual ontology underlying the phenomenon of aspectual type coercion, where linguistic devices like tenses, aspects, and adverbials transform entities of one type into contingently related entities. The authors present examples to illustrate how progressive and perfect auxiliaries coerce their inputs to specific types, and how adverbials like *for* and *in* modify the aspectual class of the core proposition. Finally, the paper examines the role of tense and temporal focus, suggesting that tense is an anaphoric category requiring a previously established temporal referent. The authors propose that the concept of a nucleus explains the anaphoric nature of tense and the ambiguity of *when*-clauses. They also discuss the distinction between futurates and past categories, and the role of modals in temporal reference.The paper "Temporal Ontology and Temporal Reference" by Marc Moens and Mark Steedman explores the semantics of temporal categories in language and their use in defining temporal relations between events. The authors propose an ontology based on notions like causation and consequence, rather than purely temporal primitives. A central concept is the "nucleus," which is an elementary event-complex comprising a goal event (culmination), a preparatory process, and a consequent state. Natural language categories such as aspects, futurates, adverbials, and *when*-clauses are argued to change the temporal/aspectual category of propositions under the control of this nucleic knowledge representation structure. The authors argue that the meaning of *when* is not primarily temporal but reflects its role in establishing a temporal focus, related to Reichenbach's reference time. The diversity of temporal relations conveyed in linguistic expressions arises from the nature of this referent and the organization of events and states in episodic memory under a "contingency" relation, distinct from causality. The paper also discusses the temporal/aspectual ontology underlying the phenomenon of aspectual type coercion, where linguistic devices like tenses, aspects, and adverbials transform entities of one type into contingently related entities. The authors present examples to illustrate how progressive and perfect auxiliaries coerce their inputs to specific types, and how adverbials like *for* and *in* modify the aspectual class of the core proposition. Finally, the paper examines the role of tense and temporal focus, suggesting that tense is an anaphoric category requiring a previously established temporal referent. The authors propose that the concept of a nucleus explains the anaphoric nature of tense and the ambiguity of *when*-clauses. They also discuss the distinction between futurates and past categories, and the role of modals in temporal reference.