Related to: Comments on Degrees of Radical Honesty, OB: Belief in Belief, Cached Thoughts.

"Nothing worse could happen to these labours than that anyone should make the unexpected discovery that there neither is, nor can be, any a priori knowledge at all.... This would be the same thing as if one sought to prove by reason that there is no reason" (Critique of Practical Reason, Introduction).

You don't need Kant to demonstrate the value of honesty. In fact, summoning his revenant can be a dangerous thing to do. You end up in the somewhat undesirable situation of having almost the right conclusion, but having it for the wrong reasons. Reasons you weren't even aware of, because they were all collapsed into the belief, "I believe in person X".

One of the annoying things about philosophy is that the dead simply don't die. Once a philosopher or philosophical doctrine gains some celebrity in the community, it's very difficult to convince anyone afterward that said philosopher or doctrine was flawed. In other words, the philosophical community tends to have problems with relinquishment. Therefore, there are still many philosophers that spend their careers studying, for example, Plato, apparently not with the intent to determine what parts of what Plato wrote are correct or still applicable, but rather with the intent to defend Plato from criticism. To prove Plato was right.

Since the community doesn't value relinquishment, the cost of writing a flawed criticism is very low. Therefore, journals are glutted with so-called "negative results": "Kant was wrong", "Hegel was wrong", etc. No one seriously believes otherwise, but writing positive philosophical results is hard, and not writing at all isn't a viable career option for a professional philosopher.

To its credit, MBlume refrains from bringing up Kant in his article on radical honesty, where he cites other, more feasible variants of radical honesty. However, in the comments, Kant rears his ugly head.