"what already I know about other similar people" But it doesn't work that way. Some properties get associated to members of a class, while others do not. Let'

"what already I know about other similar people" But it doesn't work that way. Some properties get associated to members of a class, while others do not. Let's take discrimination on the basis of blood type personality theory in parts of Asia. Many people in Japan believe that one's personality is strongly affected by one's blood type. Quoting from https://en.wikipedia.org/wiki/Blood_type_personality_theory https://en.wikipedia.org/wiki/Blood_type_personality_theory : > Many people have been discriminated against because of their blood type. Employers ask blood types during interviews despite the warnings they have been given. Children at schools have been split up according to their blood type. The national softball team has customized training to fit each player's blood type. Companies have given work assignments according to their employee's blood type. Yet all evidence is that there is no basis for this form of discrimination. It's pseudoscience akin to discrimination based on one's astrological sign. So it's clear that discrimination can rise even without a meaningful prior for a given attribute. We can also look at left- vs. right-handedness for an example of varying levels of discrimination even when the underlying genetics and thus putative justification for discrimination hasn't changed. To copy a quote from https://en.wikipedia.org/wiki/Bias_against_left-handed_people#Forced_use_of_right_hand https://en.wikipedia.org/wiki/Bias_against_left-handed_peopl... : > "I was educated in the USA in Catholic school in the 60s. My left hand was beaten until it was swollen, so I would use my right right [sic] hand" ... "I had a teacher who would smack my left hand with a yardstick every time she caught me writing with my left hand" ... "My fourth grade teacher [...] would force me to use my right hand to perform all of my school work. If she caught me using my left hand, I was hit in the head with a dictionary. It turned out that she believed left handers were connected with Satan." Since we know that discrimination can arise without a prior, and the level of discrimination can change even the prior does not change, it's not clear that Bayesian reasoning is a good way to understand the issue. In addition, it doesn't help understand why some factors are used to define 'similar people' while others are not. Men are far more likely to be involved in crime in the US, including domestic terrorism to white collar crime, but aren't universally discriminated against for being a member of that class. Or on the topic of white collar crime, editorials like 'Wall Street Criminals Are Still a Protected Class in America' at http://www.vice.com/read/wall-street-criminals-are-still-a-protected-class-in-america-808 http://www.vice.com/read/wall-street-criminals-are-still-a-p... highlight how the Bayesian prior is outright ignored. Thus, I'm not convinced that humans really use Bayesian reasoning as the basis for -isms.