The truth comes as conqueror only because we have lost the art of receiving it as guest. ---The Fourfold Way of India (1924)
"Bias is something bad from an epistemological point of view, but what exactly is it and how is it distinct from other kinds of epistemological error?" — Nick Bostrom (2006).
Tfd.com lists bias as "2. a particular tendency or inclination, esp. one that prevents impartial consideration of a question; prejudice.
3. a systematic as opposed to a random distortion of a statistic as a result of sampling procedure."
E.g. there's snobbery, a biased belief and irrationality that something "has to be better" because it is associated with perceived higher culture. E.g. that someone has to be right rather than another just because the someone comes from a more noble school. Or that someone has to be more right in every case because that someone inherited a famous family name and fortune.
There's northernist-bias, which is the biased belief, the irrationality that someone has to be more right in all cases simply because that someone is from the north. Southernist-bias is the biased belief, the irrationality that someone has to be more right in all cases simply because that someone is from the south.
Bacon listed what he called the idols (false images) of the mind. He described these as things which obstructed the path of correct scientific reasoning.
- Idols of the Tribe (Idola tribus): This is humans' tendency to perceive more order and regularity in systems than truly exists, and is due to people following their preconceived ideas about things.
- Idols of the Cave (Idola specus): This is due to individuals' personal weaknesses in reasoning due to particular personalities, likes and dislikes.
- Idols of the Marketplace (Idola fori): This is due to confusion in the use of language and taking some words in science to have a different meaning than their common usage.
- Idols of the Theatre (Idola theatri): This is the following of academic dogma and not asking questions about the world.
Less Wrong has a good collection of Errors, such as resulting from Cognitive Biases.