Pascal's bet
Daniel A. Gewurz
Pascal one of the great thinkers of modern times. In science we have the fundamental contributions in physics, especially for fluid dynamics, and mathematics, among other things, the probability of which was one of the founders, along with Fermat. The idea came from gambling: a friend had asked me on how best to share the mail in a game if the game was suspended before the end.
Pascal These interests are also reflected in his treatment of religious and philosophical themes, including the famous argument on faith as a wager. It is mentioned in section 233 of its Thoughts (in some editions, including the classic directed by Brunschvicg; corresponds to the cap. 164 of the Italian edition edited by Serini, which is cited here). The chapter is entitled, or at least begins with, "Finally, nothing" and its effects on a comparison between a possible infinite reward and nothing is based Pascal's wager.
bet
After some considerations that mix morality and the infinite in theory, comes the famous argument based on probability theory.
"We say: 'God exists or not?" But which side tilted? The reason here can not determine nothing: there is a half infinite chaos. At the end of the infinite distance to play a game that will come out heads or tails. On which of the two points? Second reason, you can point of either one, and not exclude either of them. "
Pascal begins by stating that the reason so can not draw conclusions on the existence of god, and appears here first inconsistency in his argument. In the following, in fact addresses the rationality of the player, if not to draw conclusions on the existence of a god, to suggest who he thinks are valid objective reasons to believe, or at least act like a believer, even if you do not hear faith. And these are reasons that are based entirely on logic and probability theory.
remind the flight, a concept of probability, central to this type of reasoning: that of expectation (or hope ). When you have a situation that can have multiple possible outcomes, such as different amounts of money won or lost in gambling, the expected outcome is an average of all these possible outcomes, weighted according to the probabilities of different outcomes. Suppose you join a game where we flip a coin, winning 10 and losing his head if we get € 2 if we get the cross. Then, assuming that the moneta dia testa il 50% delle volte e quindi che la probabilità di ottenere testa sia 0,5 (e altrettanto quella di ottenere croce), il valore atteso della vincita sarà (0,5 × 10) + (0,5 × (-2)), cioè 4. Quindi se la partecipazione a questo gioco costa una cifra maggiore di 4 euro il gioco sarà iniquo.
Conviene credere?
I dettagli del ragionamento di Pascal non sono chiarissimi, perché a tratti il suo stile è piuttosto oscuro ma, semplificando, la sua tesi è che faith in God can be chosen consciously, as in a game of chance. The expected value of payoff is infinite, while the cost to participate is finished: and then agrees to participate.
Pascal says: "Since there is equal probability of winning and losing, if you had only to gain two lives for one, already bet you would agree." Almost nobody, however, would agree to assign the exact same probability to the existence of that particular god has in mind Pascal and lack of it. It is not worth the discourse according to which, in the absence of complete information, all outcomes are equally likely. First of all, everyone has some reason to lean toward one or the other of these possibilities: it is not one of those situations where we talk about the abstract contents of an envelope that you do not know anything, or the like. And what about all other religions and philosophies and ways of thinking? If we wanted to show the utmost fairness and admit that they have absolutely no preference for any of the visions of the universe past, present, future or even remotely conceivable, then they should all have the same probability, and behold, the god of Pascal we should give a small probability.
But then Pascal says, "here is actually an infinite number of infinitely blessed by life gain, a chance of winning against a finite number of probability of loss, and what you risk is something over. " This is where the core of the speech by Pascal. At stake is what is promised to the good believers, a life of eternal bliss, while the price for participating in the "game" adapts our life to certain dictates (to believe in God, going to church, do not do certain actions, perform other). In terms of expected value, Pascal says that the prize (eternal bliss) has an infinite value and that the probability of getting it is small but greater than zero (one against a finite number). Therefore, the expected value of this "game" is infinite, and the price to pay to access it is just finished (embrace a Christian life).
How much is the life of a layman?
Now, each of the elements of this reasoning can be questioned. The values \u200b\u200bto be assigned to various aspects of the bet - necessary in order to compare the expected value with the price - they are very subjective. What "value" he impose a different lifestyle than that for which it was taken? Is it true that the probability of an eternal and blissful afterlife is not anything?
More generally, many have considered questionable whether the same set of their religious views on reasoning "utilitarian." Theories of decision-making based on maximizing the value of a function are of paramount importance in the economic and social, but not necessarily be appropriate here. Voltaire, commenting on Pascal, is able to say that this speech is' a bit indecent or childish idea of \u200b\u200bthis game of loss and gain, is not suited to the seriousness of the topic. "
In all then, even if one were convinced by Pascal's arguments, it is not clear how it is possible to believe at will, conscious choice to utilitarian. According to Pascal, once rationally choose to believe, you start acting outwardly like a good Catholic, "taking holy water, by saying masses, and so on." and the rest follows by itself. Then again, the mail is very high point: taking a hypocritical life and betray their own intellectual integrity.
But above all, it is not clear why a hypothetical god should appreciate this kind of faith "subject". It could not but appreciate the sincerity of the intentions of assertiveness at the table? Or maybe you simply have decided at the outset who will be saved, as in Christian doctrines, even those who believe in predestination?
A site and a movie
Who wants to deepen, the board detailed the entry of the encyclopedia online philosophy at Stanford University: http://plato.stanford.edu/entries/ pascal-wager . For a more lenient approach, the Pascal's wager, with some interesting applications to Marxism and the relationships between men and women, occurs in the conversations of the protagonists of the film My Night at Maud by Éric Rohmer.
![1 fiori[6]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhstftLK87hxwBMefnr2ovMP2d0C4kXIDy4UDy5w2RiXH_G72Y0GALh1a1Vk5yTpQCcEu6g9qvwVawYE9w6a8s6vLX5qGLfvohQkdOn3HoeSP5WcWNitN-7kWt1VXeFCwNfUG-cbvol2N0/s1600-h/1%20fiori%5B6%5D%5B2%5D.gif "1 fiori[6]")
![0 fiori[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg56D_PPKJvmVVDl3xh79eUVmrLlexzfop379xdHmaA0u3P4FXfgwo1zsP00zz6sRZ8rhmyKZJi_f6jyE3OuvxrGNcETD5hK5ckskjar9H-FaVLUZpR6tm8LRfmw9heCCjNDST9DGTW12c/s1600-h/0%20fiori%5B4%5D%5B2%5D.gif "0 fiori[4]")
