This is a long overdue post. A topic that has come up on many occasions, and is fundamental to disputes between rationalists and anti-rationalists, is that of bias. There are many misconceptions surrounding the topic of bias, and I'd like to try to clear them up. And so, I formulated seven principles of bias:
1. Everyone is biased
And I mean everyone. Every single person, in every assessment that they make, has all kinds of biases. Sometimes it is as obvious and powerful as confirmation bias - the tendency to interpret matters in a way that confirms one's prior views. At other times it can be as subtle as emotional associations, either positive or negative, with something from one's childhood. No person is a computer.
2. There is nothing wrong with being biased
Being biased is part of the human condition. It hampers one's ability to objectively appraise a topic, but that handicap does not reflect badly one someone any more than a physical handicap. For example, as someone who grew up Jewish and lives in Israel, of course I am biased towards seeing Israel as the good guy in the Israel vs. Palestinian conflict. There's no shame in that bias.
3. Being biased doesn't mean that you are wrong
This is a corollary of the first principle; since everyone is biased, of course being biased cannot mean that one is wrong. And even if, in a dispute, one person is substantially more biased than the other, it still does not mean that he is wrong.
4. There are different degrees of bias
This is an extremely important point. Although everyone is always biased, the degree of bias can be so drastically divergent that it becomes qualitatively different. Confirmation bias is extremely powerful. Confirmation bias to one's religious worldview is often fundamental - which means that even overwhelming evidence will not convince someone that their position is false.
5. Bias affects credibility
As noted earlier, being biased has nothing to do with being wrong. However, it justifiably affects credibility in the eyes of others. When evaluating claims, we put a certain degree of trust in the person making the claim (which varies depending on how much we can research the evidence ourselves). To the extent that the person is biased, there is less basis for this trust.
6. People who do not acknowledge their biases are more likely to be crippled by them
Many people believe that they are able to be fully objective in evaluating claims - even those which run counter to their deeply-held beliefs. They further believe that by claiming themselves to be objective, this is reason for others to accept that they are objective. Not only is this false, but in fact the reverse is often true. People who delude themselves into thinking that they are objective are even more likely to fool themselves in other areas. The first step in overcoming bias is acknowledging its existence.
7. There can be clues that someone lacks fundamental bias and/or has the ability to overcome it
This has be handled carefully. There can be clues that someone else, or oneself, has the ability to overcome bias, at least in certain areas. One clue is that the person has demonstrated the ability to admit error in the past. (However, this is not always a valid indicator; sometimes there is a "born-again" mentality in which there is a drive to cleanse oneself by denouncing a former way of life and of thinking.) Another clue is that a person is freely able to admit to certain weaknesses in their position and strengths in their opponent's position, even if overall they consider themselves to be correct.
These are the principles that I came up with - I'd be glad to hear other people's reformulations or additions.