The Prisoner's Dilemma and Pragmatism

Let's state The Prisoner’s Dilemma explicitly. Just 'cause I'm in a mood.

Suppose two criminals have together robbed a bank. Police have captured and are
interrogating them both. The police could get them both on a lesser charge (say, reckless
discharge of their weapons) even if neither confesses on the big charge (the armed robbery).

They are interrogating the prisoners in separate facilities, thus with no chance to communicate.

The police offer each prisoner, simultaneously, the following deal:

“Confess, ratting on your buddy, and you will be set free. We will convict your buddy and he will
serve three years in prison. If you refuse to confess, your buddy may well take this same deal,
and you will serve three years in prison, he will walk free.

“If you rat on him and he rats on you, we’ll have to convict and punish both of you.But we won’t w
ant your cooperation to go unrewarded, so in that case we promise a one-year cut on your
sentence, from 3 years down to 2. We’re also offering that as part of your buddy’s deal, too.

“Oh, and by the way, if nobody talks, then nobody will get the three year sentence, but BOTH of
you will get  one year on reckless discharge -- we don’t need any confession for that.”

So in shortened form:

Both talk: each gets two years.

Only one talks, that one goes free, the other gets three years.

Nobody talks, each gets one year.

As graphed above.

What is fascinating about this from the point of view of game theorists and social philosophers is
that purely rational self-interest, pursued by each prisoner/player, leads to a worse result for both
than less rational seeming solidarity (and silence).

It is in the rational interest of each player to talk to the police. Why? Because whatever the “other”
fellow does, confessing gets “me” the best result. If  Other talks it is better for Me to have talked
than not to have talked (two years rather than three). If on the other hand Other stays silent, it is
again better for Me to have talked than not to have talked (walking free is better than doing one
year). Other must EITHER  talk OR stay silent, so that exhausts the possibilities, and in both
cases, I am better off if I have talked.

But … it is better for both of us if both of us refuse to do that rational self-interested calculation,
and simply refuse to talk. After all, if both prisoners follow the reasoning above, each talks, and
they each do two years. If both stay silent, each does just one year.

Silence is better pragmatically, although talking ‘should’ be better from the point of view of
individual self-interested rationality. Thus, pragmatic consequences prove the  vulnerability
individual self-interested rationality.