Genealogy and the genetic fallacy: can the history of a value ever count against it?
Every introductory logic course warns against the genetic fallacy: where a belief came from does not settle whether it is true. Your racist uncle may believe the earth is round, and it is.
And yet a whole style of moral philosophy works by telling the history of a value. Nietzsche's On the Genealogy of Morality (1887) asks how our moral values were produced, and by what kind of life, before asking whether they are true. The Frankfurt School, where I do most of my reading, did something similar with the values of bourgeois society.
Two things I want to put on the table.
First, what Nietzsche thought follows from his genealogy is itself contested. Some readers take him to deny that there are any objective values; others think he ranks values by standards he plainly takes seriously, such as health or the affirmation of life. I do not want to settle that here, only to note that the genealogy does not interpret itself.
Second, Bernard Williams pointed out that genealogies can vindicate as well as debunk. His later book on truthfulness tries to show that the value we put on truth would survive learning its history.
So my question for discussion: when does learning where a moral belief came from give you a reason to trust it less? My provisional answer is that it matters when the history shows the belief would have been held whether or not it was true, because it served someone's interest. But I am not sure that test can be applied to morality without assuming some moral truths to measure against.