Tom Johnston

Tom Johnston received his doctorate in Philosophy from the University of Georgia in 1978. His current interests are in truth-functional and also mental-representational semantics, and in pragmatics, especially speech act theory, conversational implicature rules, and the distinction between speaker meaning and sentence meaning.

His working career has been in end-user IT, primarily in data modeling and architecture, in such industries as education, credit reporting, credit card management, telecommunications, healthcare, and health insurance.

In his recent book, "Bitemporal Data: Theory and Practice" (2014, Morgan-Kaufmann), he describes how an Aristotelian-based upper ontology, implicit in and common to all relational databases, can subsume definitions of database-specific tables, column, and domains, thus providing a unifying semantics for data across all those databases.

In that same book, he uses propositional attitudes and speech acts to add a third modality to the bitemporal dimensions currently defined in the ISO 9075 SQL standard. This third modality associates agent+time-interval-relative speech acts with the statements made by rows in database tables. These are propositional attitude speech acts (expressing, for example, assertions and withdrawals of assertions.)