Notes

Key terms
Accuracy: the extent to which our beliefs reflect the way things actually are, much like a map reflects the way a territory is. The concept of accuracy applies not only to binary beliefs but also to degrees of confidence. For example, if the cat is not on the mat, then believing that the cat is definitely on the mat is less accurate than believing that it's probably on the mat.

Argument: a series of claims presented as support for a conclusion.

Bias blindspot: the tendency not to recognize biases as they affect us, due to the fact that the processes that give rise to them are not transparent, even when we recognize them in others.

Biased opponent effect: a result of the introspection illusion. Given that we think our own reasoning is unbiased, and that our opponent comes to very different conclusions, we commonly conclude that their reasoning must be biased.

Binary belief: treating beliefs as if they are on/off. For example, we either believe that the cat is on the mat or that the cat is not on the mat, without allowing for different degrees of confidence.

Considering the opposite: a technique to reduce biased evaluation of evidence, where we ask ourselves either one of two questions: (i) How would I have treated this evidence had it gone the opposite way? or (ii) How would I have treated this evidence if I held the opposite belief?

Decoupling: separating our prior degree of confidence in a claim from our assessments of the strength of a new argument or a new piece of evidence about that claim.

Degrees of confidence: treating beliefs as having different levels of certainty. Just as we can be absolutely sure that x is true or false, we can have every level of certainty in between, e.g. thinking that x is slightly more likely to be true than false, very likely to be true, etc.

Evaluation stage: the second stage in the reasoning process, when we assess the strength of the potential evidence we’ve gathered.

Evidence: a fact is evidence for a claim if coming to know it should make us more confident in that claim. The notion of evidence is more rigorously defined in Chapter 5.

Introspection Illusion: the misguided assumption that our own cognitive biases are transparent to us, and as a result, that we can diagnose these biases in ourselves through introspection.

Optional stopping: allowing the search for evidence to end when convenient; this may skew the evidence if (perhaps unbeknownst to us) we are more likely to stop looking when the evidence collected so far supports our first or favored view.

Possibility freeze: the tendency to consider only a couple of possibilities in detail, and thereby end up overly confident that they are correct.

Restricted search: the tendency not to seek out the full range of alternative views or the full range of evidence that favors each view. Along with biased evaluation, this is an instance of confirmation bias.

Search stage: the first stage of the reasoning process, where we identify a range of possibilities and any evidence that may support them.

Suspiciously unexplained set (SUS): we have a SUS when every relevant consideration concerning a belief seems to go the same way, even when they are independent. This should lead us to worry that at some level our goal isn't just accuracy.

Updating on the evidence: revising our prior beliefs in response to new evidence, so that our confidence in a belief will match its degree of support.

Updating stage: the third and final stage of the reasoning process, when we revise our degree of confidence appropriately.