Intellectual laziness is one example. If someone heard about this blog but prefers not to read it, because he doesn’t care much about having truer beliefs, then this doesn’t automatically relieve him of responsibility for having biases beliefs.

An even better example is self-deception. Self-deception is surely a form of bias, but self-deception operates not only by leading a person to believe falsely in the face of contrary evidence, but also (perhaps primarily) by causing him to be ‘lazy’ in gathering certain kinds of information that might force him to correct his beliefs.

Perhaps you’d want to leave intellectual laziness out because it operates across the board. But intellectual laziness may be focused even when there’s no self-deceptive motivation at work. Perhaps someone just developed the habit of avoiding reading articles about science — perhaps such an article bored him a long time ago, although reading such articles wouldn’t bore him now or even take a great effort. Won’t we say that this is a bias?

I take laziness to be aversion to work, and aversion to something influences what is practically rational for someone.

General intellectual laziness would be likely to lead to generalised inaccuracy in belief, (but cf Bishop, Michael. “In Praise of Epistemic Irresponsibility: How Lazy and Ignorant Can You Be?” in Synthese, 2000, 122: 179-208, available at http://www.niu.edu/phil/~bishop/Research.shtml) but general inaccuracy of belief is not bias and is not what I mean by systematicity when talking about bias. I mean either irrationally skewed belief about some topic of knowledge or specific kinds of error in the use of specific kinds of evidence.

Now, it might be the case that this means that Bob has a bias against doing intellectual work, although in at least one sense of the word I think he would not be biased if his systematic error did not result “directly” from the influence of some factor whose function is not to maximize accuracy of belief.

More importantly, however, even if Bob had a bias about the rewards of intellectual work, I don’t think that would mean that he was also biased about all other topics which are such that his beliefs about these other topics would change if he did more intellectual work. It would seem that on your explication Bob’s possible bias about the merits of intellectual work would spill over to make him generally biased about almost everything.

Robin, yes bias does seem closely tied up with “illegitimate considerations” – I think we are playing around with different attempts to develop and clarify this general idea.

Bob’s not biased under my defn. Bob’s intellectually lazy so this increases the expected cost to him of acquiring new evidence. Under my defn: 1. He might not be irrational in belief because laziness mades the expected cost of evidence acquisition outweigh his expected cost of being wrong. 2. He might be irrational in belief but not biased because the irrationality is not systematic.

The problem here is clarifying “intellectual resource.” If I think better of my friends so they will like me more, and then pass more relevant info to me, is that good resource management or bias?
It seems that there is an intuition here of legitimate vs. illegitimate costs one may consider.

I take your point that conserving intellectual resources is not the only non-rational non-biasing driver. Inserting “directly” as Guy suggests might help.

The idea was that when diagnosing bias we should set aside shapers of our beliefs when those shapers are things like lack of time, effort, areas of interest, computational limitations etc. These shapers, one might say, are not trying to shape our beliefs in any particular way. They are, in some sense which I’m not yet sure how to express exactly, neutral vis-a-vis the content of out opinions: their function is not to make us believe p rather than not-p, or vice versa, although they may have indirect effects on what we believe by causing us to spend more time acquiring or evaluating evidence on some topics rather than others. We can use Guy’s term “directly” as a placeholder for this idea, but I think it would be possible to replace this with a more precise explanation.

Nick S proposes to define bias as systematically irrational belief, where a belief can be irrational if it would have been practically rational for us to have acquired more evidence. (Is this a correct interpretation of what he said?) One worry I have about this is that it might indicate bias too often. Bob is intellectually lazy. It would be practically rational for him to acquire more evidence (and do more thinking) about a wide range of topics. It would then seem on NickS’s account that most of Bob’s beliefs on these topics are irrational (because his probability assignments would change if he investigated more). Nevertheless, all parts of Bob’s brain, insofar as they work on forming beliefs at all, aim exclusively for the truth; and Bob is perfectly calibrated. His intellectual machine uses all the time and fuel it gets with optimal efficiency to generate accurate beliefs. It seems to me that what is wrong with Bob is not that he is biased.

(Another point: bias can be a property of different things. When we ascribe bias to a person, I think we are usually also ascribing to that person a measure of epistemic blame. This is not so when we ascribe bias to sub-systems or capacities, e.g. the perceptual system or one’s capacity to estimate probabilities. Finally, bias can be a property of one’s evidence (‘a biased sample’) even when one isn’t in a position to be aware of this and all of one’s relevant sub-systems/capacities are in perfect order.)