As he does elsewhere, Pascal here sets up powerful binary oppositions between philosophies and exploits their reciprocal failings and strengths. Scepticism is modest in its claims, yet impotent and negative; dogmatism (roughly, rationalistic neo-Stoicism) is presumptuous and yet has some purchase on the real world. Philosophy is therefore incapable both of knowing humanity and of taking action. Pascal finds a way beyond this impasse by exploiting his insight about the infinitely great and the infinitely small in a novel manner: humans are everything with respect to nothing, and nothing with respect to everything (God and the cosmos). They are also imbued with a desperate desire for certainty, and cannot suspend their judgment indefinitely, because they are subject to an existential imperative: ‘you must take on the bet, for you are in the game’ (Pascal 1670: 550).

This is the context of the famous wager argument, which had been used before Pascal by other apologists. Either God exists, or he does not: if human life is vain and wretched (as Pascal believes he has demonstrated), humans have nothing to lose by betting on the next life (that is submitting to the Christian religion), for they have lost nothing in the case of God’s nonexistence, and gained everything if he does exist. Some have seen this argument as purely rhetorical; others have accused it of being a case of petitio principii (the worthlessness of life is presupposed in the conclusion that we have nothing to lose in sacrificing the allegedly vain pleasures of this world); yet others see in it an ingenious example of decision theory avant la lettre.

Whatever interpretation is given to it, it can be seen to be particularly apposite to the potential constituency of libertines and gamblers whom Pascal was intending to address. Pascal’s apology is therefore not simply fideistic, postulating the two truths of faith and reason; it employs both faith and reason, as well as doubt, to achieve certainty. As one pensée has it ‘one must doubt in the right way, assert in the right way, and submit in the right way’ (1670: 523).

Descartes tried to demonstrate too much, and relied on his cogito to gain knowledge of an infinite and hence incomprehensible God; Montaigne doubted too much, and did not agonize enough about his passive acceptance of ignorance and hedonism; only Pascal (and his mentor St Augustine) used reason to affirm, to negate and to recognize its own limitations appropriately. In the second part of his apology, Pascal planned to use arguments from Biblical history, prophecies, miracles, and above all else the interpretation of Holy Writ to present the case for the truth of Christianity; but he conceded that such proofs were not absolutely convincing, although they were sufficient to secure the consent of those who read them free from the perverting effects of their own corrupt passions.