  The final years of Pascal's life were devoted to religious controversy, to the extent that his increasingly poor health permitted. During this period, he began to collect ideas and to draft notes for a book in defence of the Catholic faith. While his health and premature death partly explain his failure to realise that ambition, one might also suspect that an inherent contradiction in the project's design would have made its implementation impossible. Apologetic treatises in support of Christianity traditionally used reasons to support religious faith (e.g. a proof of God's existence, or historical arguments to show the credibility of witnesses whose evidence is reported in the New Testament); however, according to Pascal's radical theological position, it was impossible in principle to acquire or support genuine religious faith by reason, because genuine religious faith was a pure gift from God. Pascal had collected his notes into bundles or liasses before he died, and had provided tentative titles for each bundle; however, these notes gave no indication of the order in which they should be read, either within a given bundle or even between various bundles, and subsequent editors failed to agree on any numbering system for the posthumously published notes. The most frequently quoted modern editions of the Pensées—those of Lafuma, Sellier, or Le Guern—provide concordances to the numbering systems adopted by alternative editions. Given the status of the Pensées as a posthumously published notebook, it also remains unclear whether Pascal endorsed the opinions that are recorded there, or whether he planned to use some of them merely for comment or critique. They are reliably attributed to Pascal only when he expressed similar views elsewhere. One of the most famous and most extensive notes in the Pensées (Fragment 397: II, 676–81) is the so-called ‘wager’ in favour of belief in God.