Abstract
The study presents an analysis of the logical ideas and of the processes of conducting demonstrations in Principia Mathematica. In the first step, the primitive ideas of elementary proposition, elementary propositional function, assertion of elementary proposition, assertion of elementary propositional function, disjunction and negation are introduced and the theory of deduction is developed.
In the second step, the primitive ideas of proposition, propositional function, assertion of proposition, assertion of propositional function, disjunction, negation, general quantifier and individual are introduced and the theory of apparent variables is developed. The study than focuses on three questions arising from later approaches to logic: the undefined status of primitive ideas, the non-descriptive and non-prescriptive use of rules and the original identity of expressions in both their assertions and assertions about their meaning.
Thus, the analysis is presented not as a mathematical object, but as a path of thought.