Why does contractarian ethics use bargaining theory?

Because it grounds morality in agreement among self-interested agents, contractarianism needs a precise account of which agreement rational bargainers would reach; bargaining theory supplies solution concepts that select a determinate outcome.

What is the baseline problem?

It is the difficulty of specifying the non-agreement starting point from which agents bargain. If the baseline reflects an unjust status quo it distorts the agreement, but constraining it fairly seems to require moral premises a self-interest-based theory wanted to avoid.

Bargaining and Rational Agreement

Bargaining theory supplies the formal apparatus that contractarian ethics uses to specify which agreement rational, self-interested agents would reach, including the baseline from which they bargain and the division of cooperative gains.

Definition

Bargaining in contractarian ethics is the modelling of moral or political agreement as the outcome of a bargaining game among rational agents, in which a solution concept selects a determinate division of cooperative surplus from a specified non-agreement baseline.

Scope

This topic covers the use of game theory and bargaining models in contractarian ethics: the choice of a bargaining solution, the specification of a fair initial baseline, and evolutionary accounts of how social conventions and norms could emerge without a literal agreement. It examines how rational-choice tools both support and pressure the contractarian project, and does not address the moral-impartiality foundations of contractualism.

Core questions

Which bargaining solution best captures rational agreement among self-interested agents?
How should the baseline or threat point from which agents bargain be fixed?
Does a fair baseline smuggle moral assumptions into a supposedly self-interest-based theory?
Can norms arise through evolution rather than explicit agreement?

Key theories

Minimax relative concession: Gauthier's proposed bargaining solution requiring that the largest relative concession any party makes be as small as possible, used to specify the principles rational cooperators would accept.
Evolutionary accounts of the social contract: The approach of Binmore and Skyrms explaining how conventions of fairness and cooperation could emerge and stabilize through repeated interaction and evolutionary dynamics, without a deliberate agreement.

History

Gauthier (1986) brought axiomatic bargaining theory into moral philosophy, proposing minimax relative concession and a Lockean proviso to fix the baseline. Binmore (1994) reworked the contractarian project using the Nash bargaining solution and evolutionary game theory, while Skyrms (1996) showed how conventions of justice and cooperation could emerge through evolutionary dynamics rather than explicit deliberation.

Debates

Choosing the bargaining solution: Different solution concepts, such as Gauthier's minimax relative concession and the Nash solution, yield different distributions, so the choice among them appears to require a prior normative judgment.
Fixing a non-question-begging baseline: Whether the proviso constraining the initial bargaining position can be justified on grounds of rational self-interest alone, or covertly imports moral premises, is a central objection to the contractarian program.

Key figures

David Gauthier
Ken Binmore
Brian Skyrms
John Nash

Seminal works

gauthier1986
binmore1994
skyrms1996

Frequently asked questions

Why does contractarian ethics use bargaining theory?: Because it grounds morality in agreement among self-interested agents, contractarianism needs a precise account of which agreement rational bargainers would reach; bargaining theory supplies solution concepts that select a determinate outcome.
What is the baseline problem?: It is the difficulty of specifying the non-agreement starting point from which agents bargain. If the baseline reflects an unjust status quo it distorts the agreement, but constraining it fairly seems to require moral premises a self-interest-based theory wanted to avoid.