Two points about Rawlsian deliberation are that it is (a) public and (b) exclusivist. It is public in that it involves citizens deciding on their basic social and political arrangements, not (say) my deliberating on what type of car to buy.
It is exclusivist in that it disallows from public deliberation any ideas or arguments promoting 'substantive conceptions of the good',comprehensive views about what constitutes a good and valuable life - such views as are found in Christianity or Islam (in any of their versions), Judaism, Buddhism and the like. Rawls has no desire whatever - on the contrary - to impede the observance of any such views in the private lives of individuals or groups. His political point can be illustrated as follows : if as citizens we are deciding on our basic social and political arrangements, it is ruled out for me to say, 'We must do this, because it is laid down in the New Testament'. It may indeed be so laid down (not that the NT has much to say about politics) but this gives a Buddhist no reason for action. Public deliberation has to be conducted on shared assumptions.
Deliberation in Rawls
The starting-point of Rawls' political philosophy is what he calls "the fact of reasonable pluralism": Wherever conditions of free inquiry and expression obtain, citizens
tend to develop different and incompatible views about what is right and wrong, and
what constitutes a good and valuable life. Furthermore, the plurality is reasonable in
the sense that we find it also among people we consider to be intellectually sophisticated. This plurality can only be reduced though coercion or manipulation that would
violate citizens' basic rights and freedoms.
Given this reasonable pluralism, Rawls asks: how is it possible that a democratic
society can function well and remain stable over time, even though its citizens hold
quite different, albeit reasonable, views of which goals society should pursue? His
reply is that we need to adopt a kind of exclusivism, and thus conduct public deliberation without falling back on motivations and arguments derived from our comprehensive doctrines. This is particularly important whenever "constitutional essentials
and questions of basic justice" are at stake. In other spheres, gathered under the name
"background culture", citizens should have the right to embrace and advocate more
or less any comprehensive doctrine as they see fit, as long as they respect exclusivist
restrictions in public deliberation.
So why exclude comprehensive doctrines from public deliberation? Here, we need
to keep Rawls' social contract-approach to political philosophy in mind. In the "original position", citizens situated behind a veil of ignorance which deprive them of
knowledge of their abilities and social status, as well as their respective conceptions of good, agree to submit to coercion in exchange for the benefits of a stable society.
They will nevertheless object to coercion on grounds they cannot accept as valid. Now,
Rawls argues, in pluralistic societies, any grounds for coercion that presuppose the
truth of some comprehensive doctrines will be rejected as illegitimate by a significant
number of citizens. Widespread use of comprehensive doctrines in public deliberation marginalizes minorities, which may not consider future participation worthwhile. We may expect that the willingness to comply with majority decisions declines
Why is this kind of society not stable? Well, it may be stable on the surface if the
majority is stable, and minorities only express their dissatisfaction by silently withdrawing from public deliberation. It fails, however, to be stable for the right reasons,
and shifts in the relative strength of different comprehensive doctrines open for bitter conflicts.
In exclusivist societies, on the other hand, even those who disagree with some
or several majority decisions will feel obliged to comply with them, since they can
acknowledge the motivations and grounds offered, even in the cases where they disagree with the decision in question.
As a substitute for comprehensive doctrines in the public sphere, Rawls presents
public reason, which consists of well-established knowledge and insights from common sense and science (disputed and controversial points excluded), and the normative
principles of justice that we would agree to behind a veil of ignorance. The first of
these principles is The principle of liberty, stating that "each citizen has a right to
the most extensive freedom which can be combined with the same degree of freedom
for everybody else". The second principle, subordinated to the first, can be split into
two "sub-principles": The difference principle, which states that "social and economic
inequalities are only acceptable if they benefit the weakest in society", and The prin-
ciple of fair opportunity, which states that society should be ordered in such a way
that "social and economic privileges are tied to positions that are open to all".
claims that public reason gives sufficient guidance for most, if not all, questions of
public deliberation. (Ulf Zackariasson, 'A Critique of Foundationalist Conceptions of Comprehensive Doctrines in the Religion in
Politics-Debate', International Journal for Philosophy of Religion, Vol. 65, No. 1 (Feb., 2009), pp.
11-28 : 13-14.)
Ulf Zackariasson, 'A Critique of Foundationalist Conceptions of Comprehensive Doctrines in the Religion in Politics-Debate', International Journal for Philosophy of Religion, Vol. 65, No. 1 (Feb., 2009), pp. 11-28.
There is a large literature on the nature, coherence and validity of public reason. The issues are too numerous and complex to go into here but you might look up :
Robert Westmoreland, 'The Truth about Public Reason', Law and Philosophy
Vol. 18, No. 3 (May, 1999), pp. 271-296.
Fred M. Frohock, Public reason : mediated authority in the liberal state. ISBN 10: 080143677X / ISBN 13: 9780801436772.
Natural Law and Public Reason, ISBN 10: 0878407669 / ISBN 13: 9780878407668
Published by Georgetown University Press, United States, 2000.