Rorty, Richard. “Putnam and the Relativist Menace,” Journal of Philosophy 1993 vol. XC (9) pp. 443
One of the more frenetic topics in contemporary epistemology is warranted assertability — i.e., what it is rational to put forward as an assertion. Much of the issue depends on what the whole point of an assertoric speech act is supposed to be, and whether or not the point of assertion can be articulated in terms of constitutive norms. Some folks like Timothy Williamson argue that you are only warranted in asserting things you know, since the whole point of assertion is to transfer knowledge. If you assert something you don’t know, then the listener is entitled to resent the assertion, and (presumably) it is also rational for you to be ashamed of having made the assertion. Others argue that this is a very high bar, and that it makes more sense to say that you might be warranted to just assert a reasonable belief. If you assert something as true, without actually knowing it is true, then it might not be rational for you to be ashamed of yourself, nor does it follow that others are entitled to resent you for what you’ve said.
What does Richard Rorty think? Rorty argues that you are only warranted in asserting something so long as what you say is acceptable in a linguistic community. “So all ‘a fact of the matter about whether p is a warranted assertion’ can mean is “a fact of the matter about our ability to feel solidarity with a community that views p as warranted.”” (p.452-453) Rorty argues that the conditions where it is warranted to assert are relative to how we feel about the views that would be held by an idealized version of our own community. That is the sense in which he’s a relativist. What you say in one speech community might be assertable, and what you say in another would be totally verboten. As far as Rorty is concerned, assertability is concept that belongs to sociology and not epistemology.
For Rorty, the meaning of “our community” or “our society” is determined by common ground. For example, he uses the term “wet liberalism” to describe the community that Rorty and Putnam share, as if the fact that they both belonged to the liberal tradition was what set them into the same community. (p.452) (I don’t think that it’s necessary for us to make reference to political ideology when we talk about “our linguistic community”, but it’s at least one candidate.) Whatever criterion you use to pick out the relevant linguistic community, there is a sense that you have got to be in solidarity with that community. (453-54) The upshot: for the purposes of making a rational assertion, you’ve first got to assume you’re part of a common trust.
Now for the weird, relativist twist: Rorty thinks truth is all about deference to the idealized community of future knowers. If you say, “Rutabegas are red”, then that claim is true just in case a future idealized version of yourself would say it too. So long as Rorty is concerned with the notion of truth, he thinks we are interested in whether or not an idealized future society of knowers would affirm or deny what we’ve said. (p.450) Truth is just a vague term of approbation, synonymous with truth; and, evidently, trust is the ultimate truth-maker.