You and your partner in crime are in
custody. You are kept in separate cells and cannot talk with each other. Of
course, you both will try to minimize your sentence if convicted, and the
sentence of each of you will depend on whether or not you confess and gives evidence
against your partner. If both of you deny and keep silent about the other, each
of you will get a sentence of two years in prison for some minor crimes. If
both of you confess and testify against the other, each of you will get 10
years. If you confess and testify against your partner and the latter denies
and keeps silent about you, you’ll get one year and your partner will get a
sentence of 20 years; and the other way round. See this schema:
Your possible sentences are first in each cell
and the related possible sentences of your partner are second.
The best for both of you is to deny your
involvement in the crime if the other does as well, but how do you know that the
other will deny? For if one confesses and gives evidence against the other,
while the other denies, the former will be better off. We call this problem the
Prisoner’s Dilemma.
There are many versions of the Prisoner’s
Dilemma. One version is the Tragedy of the Commons, first presented by Garrett
Hardin in 1968. It runs as follows: As happened and still happens in many parts
of the world, herdsmen often pasture their herds on the common grounds of the
community. If every herdsman increases his herd, at a certain moment the
commons will have reached their maximum capacity for grazing. However, “as a rational being, each herdsman seeks to
maximize his gain. Explicitly or implicitly, more or less consciously, he asks,
‘What is the utility to me of adding one more animal to my herd?’ ... The
rational herdsman concludes that the only sensible course for him to pursue is
to add another animal to his herd. And another; and another….” (Hardin, p.
169). Now it is so that the effect of adding one animal on the quality of the
pasture lands will be so small, that nobody will notice it. Moreover, the costs
of the damage of each animal added will be shared by all herdsmen, while the
gains will go to the owner of the added animal. Usually these gains are higher
than the additional costs (for the owner!). Therefore it will be rational for
each herdsman to add livestock to his herd beyond the capacity that the commons
can bear. This will go on till the system crashes and each herdsman earns less
than he got before the commons had reached their maximum capacity.
This is what we see now – so Hardin warns
us (p. 169) – in the problem of global pollution and, as I want to add – for when
Hardin wrote his article, it was not yet a topic – in the problem of global
warming (which actually is a pollution problem). But the Tragedy of the Commons
doesn’t only point out the essence of the problem of global warming, but also
why a solution is so difficult. For in the short run, it is you who profits by your
pollution that contributes to the global warning, but the costs go to
everybody. And why wouldn’t you go on producing pollution then? For if you stop
doing so and others continue, you are the loser and these others gain (at least
in the short run). So the Tragedy of the Commons is a kind of Prisoner’s
Dilemma.
Hardin saw two solutions for the problem:
privatization or a kind of central authority. However, privatization is not
possible: you can subdivide the commons but not pollution, for wind and water will
bring it to your neighbour. And I don’t see that there’ll ever be a kind of
central world authority that will be more powerful than the now powerless
United Nations. Rational cooperation on a moral base between the countries
seems to be the only option, but how will it happen given the weak results of
the past international conferences on global warming? Less developed countries
will put the blame on the rich countries and say that they first must catch up.
Even if this problem will be solved, the central problem of the Tragedy of the
Commons, namely the dilemma of the conflict between individual and collective
rationality, is still there. At least in the short run (and maybe in the long
run as well), individually each person will profit by not ending his polluting
practices.There are no sanctions, and moreover much pollution by an individual
country, let alone by an individual person, has no immediate appreciable effect
on the total pollution. And why wouldn’t you cheat, if others cheat as well (or
so you think)? As Maclean states in the article that brought me to this blog:
“If no one else surrenders his rights, you would be foolish to do so; and if
everyone else surrenders his rights, you can gain further advantage by refusing
to surrender yours”. (p. 225). It’s Hobbes’ dilemma without the possibility of
Hobbes’ solution: Leviathan. But if the global pollution cannot be stopped, who
will stop the global warming?
Sources
- Hardin, Garrett, “The Tragedy of the
Commons” (1968) in Ekistics, Vol. 27, No. 160, ECOSYSTEMS: man and
nature (MARCH 1969), pp. 168-170.
- Maclean, Douglas, “Prisoner’s Dilemmas,
intergenerational asymmetry, and climate chance ethics”, in Martin Peterson
(ed.), The Prisoner’s Dilemma.
Cambridge: Cambridge University Press, 2015; pp. 219-242.
- Peterson, Martin, “Introduction”, in The Prisoner’s Dilemma (see above); pp.
1-15.
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