Coherence Bias in Bible Students

Coherence Bias is a serious problem for Bible students.  I’ll give several examples of commonly misunderstood Bible passages below, and will explain how Coherence Bias is frequently the culprit.  First, however, let’s define some terms.

What is a bias?

In cognitive science, it’s a small routine of habitual thinking that does not match perfectly with reality.  Here are three examples:

  1. “All Italians are thieves.”  Surely, some Italians are thieves, but there are a great many Italians who are not.  A person whose mind runs this “All Italians are thieves” bias, however, does not stop to consider whether any particular Italian he meets is a thief or not.  Rather, he simply lets the bias run, considering it to be a good-enough way of thinking to suit his purposes.
  2. “My favorite expert couldn’t be wrong about this.”  The assumption here is that whatever the expert says, it’s true.  Again, this saves a person the time and trouble of having to think through an issue for himself.  (And that’s a common theme with biases, by the way.)
  3. “If I were wrong about this, I’d know it.”  This is my own personal favorite of all the biases.  For one thing, I think it’s really funny.  For another, it shows the extreme hubris by which one considers himself to be invulnerable to cognitive error.

What is Coherence Bias?

Coherence Bias is a mental shortcut (an alternative to deliberately thinking something through) that assumes that if a story or situation or idea seems coherent—that is, if it seems to fit together, or to “make sense”—then it must be true.  This particularly comes into play as we interpret situations.  For example, 30 minutes after ordering a pizza for delivery, Billy hears a knock on the door and assumes it must be the pizza guy.  Why?  Because “that would make sense.”  Is it possible that it could be someone other than the pizza guy?  Of course, it is.  But Billy gives the matter no thought as he opens the door without looking through the peephole to see who it is.  Billy might order pizza, say, 20 times a year, and he might make this same assumption all 20 times.  And it may well prove to be true all 20 times.  But it could just as well be the case that the knock on the door is from an armed robber, and that Billy has made a costly mistake in opening the door.

Another classic example of Coherence Bias is this:

Test Yourself.  If you’d like to test yourself for coherence bias, one of the four questions on this quiz is relevant.  And here’s another:

The Linda Problem
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Which is more probable?

A. Linda is a bank teller.
B. Linda is a bank teller and is active in the feminist movement.”

The Linda Problem. Tversky, A. and Kahneman, D. (1982) “Judgments of and by representativeness”. In D. Kahneman, P. Slovic & A. Tversky (Eds.), Judgment under uncertainty: Heuristics and biases. Cambridge, UK: Cambridge University Press.

The Answer.  Many people get this problem wrong because they formulate a view of Linda based on the facts given about her, and they find answer B to fit in quite nicely with those facts.  But the question is one of probability, and we are not being asked whether it’s also likely that Linda, as described, would be active in the feminist movement.  No, quite specifically, we’re being asked which scenario (A or B) is more probable to be true.  The most popular answer here is “B”, but it is not the correct answer.  When it comes to probability, it is always more likely that one thing is true than that two things are true.  (This is one of the main implications of Baye’s Theorum.) Many people, however, are suckers for scenarios that seem coherent, so when they’re faced with this Linda Problem, they will ignore the question of probability and answer instead as if they were being asked whether they find it believable that Linda is also active in the feminist movement.


Here are a few Bible matters frequently misinterpreted on account of a Coherence Bias working in the mind of the reader.

1. “Paul/Saul”.  Many assume that the apostle Paul was renamed (from Saul) at his conversion.  (This article explains why this is a bad assumption.)  To many, it “just makes sense” and it’s a very “biblical” idea.  That is, they see Abram’s name changed to Abraham and Simon’s name changed to Peter, so when they get to Saul/Paul, it “just makes sense” that God or Jesus changed his name, too.  But it’s not true.  Saul/Paul continued to operate under both names.

2. “Peter, do you love me?”  In a famous discussion in John 21, Jesus asks Peter three times whether he loves him.  Many have opined that the reason Jesus asked Peter three times is because Peter had denied Jesus three times in John 18.  This would certainly be a coherent story–and dramatic, as well—but we simply do not have sufficient information from which to determine whether Jesus had this in mind.  In fact, the particulars of what Jesus asked would tend to argue against this interpretation of that discussion.  And why is that?  It’s because the first two times Jesus asked “Do you love me?”, the Greek word agape was used for “love”, and the third question used phileo instead.  It is not, therefore, the same question asked three times.  Rather, when interpreted with the meanings of the Greek words more strictly in mind, the discussion went something more like this:

“Are you committed to me (agape) …”
“Yes, you know that I am your friend (phileo).

“Are you committed to me (agape)…”
“You know I’m your friend (phileo)”

“Are you my friend (phileo)?”
“You know I’m your friend (phileo)”

The third question was indeed different, and we see a signal of this in the narrative when John tells us, “Peter was grieved because he said to him the third time, ‘Do you love me?'”  In response to Jesus’ question about commitment, Peter–now humbler than before–would only venture to speak of his affection for Jesus.  And when Jesus finally questions even that affection, Peter is troubled by the question.  Is this related to Peter’s previous denials and his boast that “Even if all these others fall away, I never will”?  Probably.  But the oversimplified idea that Jesus asked three times because Peter had denied three times is nowhere stated in the texts.  Those who insist this must be the case are going too far, and most likely because they love the coherence of the idea, even if it is unprovable.

I’ll add more examples to this list as time goes by.  Think of it as a running list on a whiteboard.