Doubling down occurs when a person is confronted with evidence against a belief and their belief, rather than being weakened, is strengthened.A plausible explanation of doubling down rests on Leon Festinger’s classic theory of cognitive dissonance. When a person has a belief that is threatened by evidence, she has two main choices. The first is to adjust her belief in accord with the evidence. If the evidence is plausible and strongly supports the inference that the belief is false, then it is rational to reject the old belief. If the evidence is not plausible or does not strongly support the inference that the belief is false then it is rational to stick with the threatened belief on the grounds that the threat is not much of a threat.

Assessment of what is plausible evidence can be problematic. In general terms, assessing evidence involves considering how it matches one’s own observations, one’s background information, and credible sources. This assessment can push the matter back: the evidence for the evidence also needs to be assessed, which fuels classic skeptical arguments about the impossibility of knowledge. Every belief must be assessed, which leads to an infinite regress, thus making knowing whether a belief is true impossible. Naturally, retreating into skepticism will not help when a person is responding to evidence against a beloved belief (unless the beloved belief is a skeptical one)—the person wants her beloved belief to be true. As such, someone defending a beloved belief needs to accept that there is some support for the belief—even if the basis is faith or revelation.

In terms of assessing the reasoning, this is objective if it is deductive logic.  Deductive logic is such that if an argument is doing what it is supposed to do (be valid), then if the premises are true, then the conclusion must be true. Deductive arguments can be assessed by such things as truth tables, Venn diagrams and proofs; thus, the reasoning is objectively good or bad. Inductive reasoning is different. While the premises of an inductive argument are supposed to support the conclusion, inductive arguments are such that true premises only make (at best) the conclusion likely to be true. Inductive arguments vary in strength and while there are standards for assessing them, reasonable people can disagree about the strength of an inductive argument. People can also embrace skepticism here, specifically the problem of induction: even when an inductive argument has all true premises and the reasoning is as good as inductive reasoning gets, the conclusion could still be false. The obvious problem with trying to defend a beloved belief with the problem of induction is that it also cuts against the beloved belief—while any inductive argument against the belief could have a false conclusion, so could any inductive argument for it. As such, a person who wants to hold to a beloved belief in a way that is justified would seem to need to accept argumentation. Naturally, a person can embrace other ways of justifying beliefs—the challenge is showing that these ways should be accepted. This would seem, ironically, to require argumentation.

A second option is to reject the evidence without honestly assessing it and rationally considering the logic of the arguments. If a belief is very important to a person, perhaps even central to her identity, then the cost of giving up the belief would be very high. If the person thinks (or feels) that the evidence and reasoning cannot be engaged fairly without risking the belief, then the person can reject the evidence and reasoning using various techniques of self-deception and bad logic (fallacies serve well here).

 This rejection has less psychological cost than engaging the evidence and reasoning but is not always consequence free. Since the person probably has some awareness of their self-deception, it needs to be psychologically “justified”, and this results in a strengthening of the commitment to the belief. There are many cognitive biases that help here, such as confirmation bias (seeking, interpreting, and remembering information to confirm existing beliefs) and other forms of motivated reasoning. These can be hard to defend against, since they derange the very mechanisms that are needed to avoid them.

One interesting way people “defend” beliefs is by categorizing the evidence against the beliefs and opposing arguments as unjust attacks, which strengthens their resolve in the face of perceived hostility. After all, people fight harder when they believe they are under attack. Some people even infer they must be right because they are being criticized. As they see it, if they were not right, people would not be trying to show that they are in error. One variation of this is when a person claims they must be right because everyone disagrees with them.

People also, as John Locke argued in his work on enthusiasm, take the strength of their feelings about a belief as evidence for its truth. When people are challenged, they often feel angry and this makes them feel even more strongly. Hence, when they “check” on the truth of the belief using the measure of feeling, they feel even stronger that it is true. However, how they feel about it (as Locke argued) is no indication of its truth. Or falsity.

As a closing point, one intriguing rhetorical tactic is to accuse a person who disagrees with you of being the one who is doubling down. This accusation, after all, comes with the insinuation that the person is irrationally holding to a false belief. A reasonable defense is to show that evidence and arguments are being used to support a belief. The unreasonable counter is to employ the very tactics of doubling down and refuse to accept such a response. That said, it is worth considering that one person’s double down is often another person’s considered belief. Or, as it might be put, I support my beliefs with facts and logic while my opponents double down.