During the last few years of his life, Pascal was writing “an apology for the Christian religion,” but extremely poor health required him to rest frequently and this prevented him from writing for extended periods of time. He was, however, able to compose eight hundred fragments that were discovered and edited after his death by his nephew Étienne Périer, who called these fragments Thoughts (Pensées). Despite the uncompleted nature of Thoughts, it contains profound insights into the myriad relationships between ethical and religious problems. Unlike his fellow mathematician and philosopher René Descartes, who had argued in his 1637 book Discourse on Method that logic alone sufficed to explore moral problems, Pascal was convinced that only an acceptance of the revealed truths of Christianity could enable him to recognize the moral foundation for a just society.

Pascal stated that there were basically two ways of dealing with moral problems. By means of “the spirit of geometry” (“l’esprit de géométrie”) one examines in a purely logical manner the many steps that are involved in resolving ethical questions. “The spirit of insight” (“l’esprit de finesse”) helps one to recognize intuitively that certain actions are morally wrong whereas others are morally correct. Although he did not deny the importance of logical reasoning for discussions of ethical problems, Pascal sensed that most moral decisions are inspired by intuitive feelings that are formed by one’s religious training and by the diversity of one’s experiences. In Thoughts, Pascal appealed to the deep emotional and psychological reactions of his readers in order to persuade them that an acceptance of “the grandeur of man with God” and “the misery of man without God” will lead people to embrace those religious and ethical values that are presented in the Bible.