The problem of certainty in Blaise Pascal

Blaise Pascal is a philosopher who has often been overlooked and poorly understood due to the scattered, incomplete and seemingly contradictory passages that remain to us. This thesis argues that reading Pascal's texts in the fields of natural science, geometrical method, philosophy, and theology in the context of the problem of certainty and within a chronology will lead to a more accurate classification, reconciliation of many contradictions, and ultimately to a more coherent structure. In this context, in the first chapter, Christian theology, Montaigne's skepticism and Descartes' philosophy, which had a direct influence on Pascal, are analyzed on the axis of the problem of certainty. In the second part of the thesis, the transformations of the discussion of the vacuum left over from Aristotelian physics until Pascal's time are discussed and the relation of these discussions with metaphysical systems is evaluated. In the continuation of the study in which we examine Pascal's contributions to the scientific method through vacuum experiments, it is observed that Pascal also prioritized Karl Popper falsificationism and the Duhem-Quine thesis in the philosophy of science. From here, we move on to compare Descartes' and Pascal's approaches to the natural sciences and conclude that Pascal was not a positivist in the full sense of the term. In the next section, where we discuss the reasons for Pascal's transition from the natural sciences based on experimentation to the geometrical method based on reasoning through the problem of infinity, the importance of the heart in Pascal's epistemology is emphasized based on the distinction between the geometrical mind and the intuitive mind. The divine and secular aspects of the heart in Pascal are discussed through the Christian myth of the Fall, and the compatibility of this secular aspect with reason is discussed through "Pascal's Wager". Finally, the relationship between faith, which Pascal sees as the ultimate certainty, and divine grace is evaluated on the axis of Christian theology.