Confusion is an important tool in our cognitive inventory. It tells us when to pay more attention. Let me give you an example.
A month or two ago, I chanced upon an unusual synthesis: libertarianism and social justice. I didn't bookmark the article in question, but this one covers the same material. The argument in question states that we fundamentally can't know what it's like to be another person--correct--and therefore white, heterosexual men should check their privilege.
At this point I found myself quite confused. I'd seen Fundamental Ignorance of Others used many times in the past. Usually, it's employed by libertarians, arguing for individualism and against state control over our lives. What was it doing here?
If we can't know other's lives, then how are we supposed to figure out who has it better off? Now, it's undeniable that an individual of European descent, male gender, or heterosexual persuasion is statistically more likely to be better off than someone who isn't. (I spent a semester in Social Problems listening to a self-described Marxist, believe me, I know.) There're a few problems with this approach however.
First, most disadvantages associated with race and gender are caused by the culture one is raised in, and by misguided government policies. Active discrimination plays a relatively small role in determining life outcomes in most cases. Nevertheless, as a rationalist and a libertarian, I'm trying to combat both bigotry and the structural causes of racial and gender inequality. Why should I be feeling guilty?
(If you don't think "privilege" implies guilt, you probably haven't spend much time on tumblr.)
More importantly, acknowledging that certain traits are statistically correlated with better outcomes doesn't tell us anything definite about the individual in question, nor how to compare two individuals in particular. You can generalize, sure, but that's kinda how this whole racism/sexism/homophobia thing started in the first place.
So why, then, are we expected to check our laundry list of privileges? How do you come so close to true individualism, and then swerve right into biocollectivist territory?
My confusion should have been a giant neon sign saying "PAY ATTENTION TO THIS." Instead of trying to figure it out, I wandered off to other posts. It never stopped bothering me, and finally I realized we were dealing with an Isolated Demand for Rigor.
Fundamental Ignorance of Others applies to everyone. Unless you're a telepath, you can only infer what other's lives are like from exterior evidence. This particular argument, however, makes strong assumptions about broad categories of people, and only then invokes Fundmental Ignorance as a defense.
This is incredibly convenient for social justice types. It allows them to shield off an entire group from criticism, on the grounds that their critics are unaware of their privilege. It may be the case that a particular individual does not appreciate the hardships [oppressed group] endures, but all too often privilege is used as a fully general counterargument.
Fundamental Ignorance of Others should not be a fully general counterargument. There will be times when insufficient data is present to make an accurate deduction, but that shouldn't stop us from evaluating each case to the best of our ability. If we're going to truly understand one another, we need to remember that inessential features are not determining factors, regardless of statistical correlation. Probabilities are just that: probabilities. This is the crux of individualism.