Azamat> I have an impression that many big problems in science and technology could be solved by recognizing Data as a Prime Ontological Category Yes, of course. That is absolutely true!!!! The failure to recognize and emphasize that point is the primary reason why the ISO standard for ontology is hopelessly obsolete. But instead of the word "Data", I recommend the more general word "Signs". That term includes every kind of language, logic, patterns, notations, books, documents, web pages, representations, images, diagrams, virtual reality... independent of any media, substrate, or equipment on which the signs may be stored, displayed, processed, or transmitted. In fact, an ontology that does not include signs as a fundamental category is incapable of representing or talking about itself. Every theory of mathematics and logic is a formal system of signs that are related by formal signs called axioms and rules of inference. For an ontology that has a two-way split at the top (Signs and Physics), see slide 30 of http://www.jfsowa.com/talks/patolog4.pdf Those are the slides for day 4 of a short course on Patterns of Logic and Ontology. For the slides of the other days, see patlog1, 2, 3, and 5. John