 In order to divide truths into different disciplines and present them in particular treatises, we first have to discover them. Such is the goal of The Art of Discovery or Heuristic, which contains rules for finding new truths. Heuristic presupposes the possibility of recognizing truths, which is the object of The Theory of Knowledge. Now, the decisive step in the exploration of the layers of science leads to the most important part of the TS, The Theory of Elements, which analyses the objective conditions of the subjective activity of knowing, namely the theory of ideas, propositions and deduction, considered in and of themselves, in short: formal logic. The Theory of Fundamentals attempts to show that these elements are propositions in themselves and ideas in themselves, that there are infinitely many truths in themselves and that we can know at least some of them. Taking all the disciplines of the TS in the due order, we obtain the following structure: