He needs to establish that justice is a matter of hearing both sides, that this demand has bite, and that it is politically neutral: it is established by a "kind of transcendental argument" as a matter of practical reason alone.
The rational ground of respect is rationality itself, the habit of balancing pros and cons in argument, a norm [we] cannot without disaster discard in [our] own thinking.Suppose we grant that the weighing of reasons in our own lives is inevitable. How is it meant to follow that reason requires us to weigh the claims of others in public discourse? Two answers are suggested by the book.
First, while "questions of fairness in the distribution of goods and of penalties are always matters of opinion and often give rise to conflicts [...] it is a necessity, and not a matter of opinion, that such conflicts should be resolved either by argument or by force." True enough; but why not opt for the latter, if one is powerful enough?
Second, in Hampshire's version of the Platonic analogy between city and soul, individual practical reason derives from public adversarial debate: "the habit of argument within the solitary soul [...] is modeled on the habit of argument within assemblies, committees and law courts."
The public situations I have mentioned give rise to corresponding mental processes [...] the idea of an individual's being unbiased, open-minded, and rational in his thinking has sense for us because we know what it is for a public procedure of discussion to be unbiased, open-minded and rational.Procedural justice as practical reason is therefore presupposed by individual rationality, which we cannot do without.
I am not sure what to make of this claim. It does not follow, as Hampshire sometimes suggests, from the platitude that we learn the language of reasoning (like all language) from its public use. And there is no other argument here.
Nor does the analogy give much content to procedural justice. After all, what does it mean to "hear both sides"? For Hampshire, the answer to this question lies in an appeal to brute convention: the contingent facts of how we happen to proceed. My suspicion is that this is the book's more basic "transcendental argument", one that is suggested by a passage in which its project is first spelled out:
I shall argue that Plato is right about the existence of the analogy between the soul and the city and also right that the concept of justice is best explained by this analogy; but I shall argue that justice cannot consist of any kind of harmony or consensus either in the soul or in the city, because there will never be such a harmony, either in the soul or in the city.This argument against justice as harmony relies on a suppressed premise: that justice is possible (as harmony is not). Despite Hampshire's claim to a "thoroughgoing skepticism and negativity", it is a kind of optimism that supports his pragmatic approach. Justice must be fair procedure, and fair procedure must be roughly what we take it to be, if there is any justice in the world. (That would explain Hampshire's praise of "shabby compromise", of politicians and statesmen who "sacrifice some of their own ideals and moral commitments for the sake of preserving their alliances.")
I respect and understand the impulse to realism in Justice is Conflict, but I am afraid that Hampshire does not see the danger here, or does not see it vividly enough. "It is the best we can manage" has often worked as an excuse for the evils of poverty, imprisonment and humiliation that he so evidently detests.