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BAYESIAN THEISM AND PASCAL’S WAGER 407
A very interesting feature of sports bet is that bookmakers, in order to attract gamblers to join
the game, normally try to justify their gambling odds with some grade of likeliness which
would seem the customers plausible and make them bet. By doing so, bookmakers take into
consideration subjective expectancies based on the known condition and skills of teams,
which, normally, are not based on frequencies.
If the gambling odds for the game Rot-Weiß Erfurt of the German third league vs FC
Barcelona is 100 for a victory of the Erfurt team or a deuce (i.e. those who bet on Erfurt’s
victory over Barcelona or deuce will take hundred times their stake if Erfurt really wins or
succeeds to keep the deuce) and 1,01 for Barcelona’s victory, then the assumed likeliness
which underlies the gambling odds for Erfurt’s victory over Barcelona or a deuce will be: 1 /
100 = 0,01. The corresponding figure for Barcelona’s victory over Erfurt will be the rest 0,99
(notice that the bookmaker offers 1 / 1,01 ≈ 0,99), which entitles for a 0,01 € gain for every €
bet on Barcelona’s victory if Barcelona wins. 2 The value 0,99 given for Barcelona’s victory is, I
repeat, anything but a frequency which resulted by use of empirical methods. It is rather a
likeliness based on a guess with which the bookmaker hopes to meet the subjective
estimations of as many potential customers as possible to make them feel justified to come
and bet. For example, the gambling odds would take for granted that Erfurt’s victory and a
deuce would be extremely improbable and would allow for a very high revenue for bets on
these outcomes, just because the public, the potential customers that is, would be intuitively
inclined to risk some low stake on Erfurt’s victory over Barcelona only if the revenue would be
extremely high. Generally, the gambling odds which bookmakers issue for the outcome of
soccer, basketball, baseball or rugby matches are normally not based on frequencies but are
supposed to pre-empt the public’s guesses of the degree of likeliness of these outcomes.
Although often there is a general agreement on these guesses, they are estimations which
reflect an utterly subjective stance.
The main reason for which the likeliness of events which underlies gambling odds reflects a
subjectivist stance is the following: neither bookmakers nor anyone else have the means to
calculate the exact degree of probability which corresponds to the gambling odds for these
outcomes. If FC Barcelona, which is supposed to be one of the strongest soccer teams
worldwide when these lines are written, would happen to play against Rot-Weiß Erfurt there
would be no prehistory of games between the two teams to result in certain frequencies for
Barcelona’s victory, Erfurt’s victory or a deuce. Therefore no gambling odds would be issued if
the gambling odds would be based on frequencies.
Let me dwell for a moment on the motivation of RWE-supporters to bet on their team’s
victory over Barcelona.
Perhaps there are a few supporters of RWE with a distorted relation with reality who really
believe that RWE has many chances to overcome in the match against Barcelona. Let us call
them obtuse RWE-supporters. They would bet on behalf of their team in order to earn money.
But most RWE-supporters are sober: their expectation to earn money for their bet on RWE’s
victory over Barcelona is fairly low. What they aim at with this bet is to demonstrate their
identification with the team by “sacrificing” the money of the stake. The risk to lose their
money is very high. However, they would bet small amounts which do not weigh much. For
the small amount they enjoy, apart of the feeling of identification with the team, the
anticipation of the – admittedly extremely improbable – case of a victory for Erfurt, which
gives an extraordinary revenue. Their stake has a double function then: they buy something
for it and it gives them the hope of earning the high revenue in case their team wins. But this
is a win-win-situation which would make sober RWE-supporters (people that is, who
2
The fictive example results in a sum of gambling odds which is above 1. As irritating as they can be,
sums over 1 depict a usual tactic of bookmakers which cannot be the subject of this paper.