Individuals draw conclusions about possibilities from assertions that make no explicit reference to them. The model theory postulates that assertions such as disjunctions refer to possibilities. Hence, a disjunction of the sort, "A or B or both," where "A" and "B" are sensible clauses, yields mental models of an…

Syllogisms are arguments about the properties of entities. They consist of 2 premises and a conclusion, which can each be in 1 of 4 "moods": "All A are B," "Some A are B," "No A are B," and "Some A are not B." Their logical analysis began with Aristotle, and their psychological investigation began over 100 years ago. This article outlines the…

The mental model theory postulates that the meanings of assertions, and knowledge about their context can "modulate" the logical meaning of sentential connectives, such as "if" and "or". One known effect of modulation is to block the representation of possibilities to which a proposition refers. But, modulation should also add relational…

Many concepts depend on negation and on relations such as conjunction and disjunction, as in the concept: "rich or not democratic". This article reports studies that elucidate the mental representation of such concepts from descriptions of them. It proposes a theory based on mental models, which represent only instances of a concept, and for each…

A hyper-emotion theory of psychological illnesses is presented. It postulates that these illnesses have an onset in which a cognitive evaluation initiates a sequence of unconscious transitions yielding a basic emotion. This emotion is appropriate for the situation but inappropriate in its intensity. Whenever it recurs, it leads individuals to a…

This article presents a theory of how individuals reason from inconsistency to consistency. The theory is based on 3 main principles. First, individuals try to construct a single mental model of a possibility that satisfies a current set of propositions, and if the task is impossible, they infer that the set is inconsistent. Second, when an…