It is a thesis, upon which this project rests, that a single abstract representation suffices for all declarative knowledge, and hence that all declarative knowledge, in whatever form it is stored, can be viewed in that universal form, permitting core deductive technologies to be this rendered universal.
Support of that thesis may come in two parts, reflecting important epistemological distinctions.
The first part concerns universality in the expression of logical truths (in the broad sense corresponding to the concept of analyticity). The second part concerns the relationship between those logical truths and the other two categories of declarative truth, distinguished semantically from logical truths by their expression of facts about the material world or valuations concerning behaviours in that world.
David Hume’s philosophy provides a tripartite partition of what can be known in two distinctions. The first distinguishes “relations between ideas” and “matters of fact”. The second comes in his insistance that one cannot derive an ought from an is. This trichotomy can be cut according to different criteria, which are often considered coincident, especially by positivists, a position contested by others, notably Immanmual Kant. The latter distinction is closely related to G.E.Moore’s observations about a naturalistic fallacy
The distinctions, as they are drawn here, are semantic. These are presented as forming a stack in which language aggregates as we pass to the higher levels, and the lower levels are logically independent of the upper.