Motivated Reasoning and Its Influence on the Evaluation of Arguments

Original text Luciano Carlos Cunha · Volume X, p. 67 of the PDF edition · English translation

5.1. Introduction

There are claims that come up in every debate about the moral consideration of animals. Consider, for example, statements such as “plants feel too” and “anything we do to help animals in the wild will only make things even worse.” These statements are often cited in an attempt to justify, respectively, killing animals for food and not helping animals in the wild.

In the rest of this chapter we will use these two claims as particular examples of the general topic we will discuss: the influence of motivated reasoning bias on the evaluation of arguments. However, it is important to remember that everything said here about these two examples applies equally to people's attitudes when offering and evaluating arguments in any situation, and not only in these two cases.

5.2. Why do people apply different levels of rigor when evaluating arguments?

Some people really do believe those two claims. However, they generally do not investigate whether or not such claims are true, and on the rare occasions when they do, they tend to carry out an analysis influenced by motivated reasoning and confirmation bias, which will be explained below.

Motivated reasoning leads us to assess questions in a biased way, seeking to confirm the belief we already held rather than trying to discover the truth. Motivated reasoning produces a confirmation bias, which consists in noticing only (or giving greater weight to) the information that confirms our initial belief, and not noticing (or giving less weight to) the information indicating that it is mistaken.

Another effect of motivated reasoning and confirmation bias is that people evaluate arguments that confirm their initial beliefs much less rigorously. For example, if someone likes the taste of products of animal exploitation, they may be tempted to accept any argument, however bad, that purports to justify animal exploitation. Likewise, if someone has an initial negative reaction to the proposal to help wild animals, they may be tempted to accept any argument, however bad, that purports to establish that we should let nature take its course.

Important: This bias (like any other bias) can affect everyone, including philosophers who specialize in ethics.

5.3. Do people always believe the objections they raise?

Now we will discuss another possibility that is often not taken into account: that the person does not believe the claim they are making, but offers it as an excuse for their beliefs and attitudes. Depending on the case, this can happen for various reasons. Some possibilities follow.

(1) Self-deception. One possibility is that the person is trying to deceive themselves. They themselves do not believe the claims they make, but they repeat them to themselves because they do not want to accept the truth or do not want to change a behavior, and they feel bad thinking that they are doing something wrong.

(2) Attempting to deceive the interlocutor. Another possibility is that the person does not believe the justification they offer, but believes that their interlocutors will accept it (or at least that they will have trouble refuting it). For example, someone may think that their interlocutors are not intelligent enough to notice the problems with the argument they offer, and that in this way they will deceive them.

(3) Attempting mutual pretense. A third possibility is that someone knows that their interlocutors will notice the problems with the argument they offer, but also realizes that the interlocutors agree with the conclusion they will defend, even though they have no good reason to accept that conclusion. The person then offers the attempted justification in the hope that everyone will pretend it is a good justification, since that way no one needs to change their beliefs or attitudes.

In fact, this third case is very common. The fact that many people repeat a bad argument makes it harder for everyone else to notice the problems with the argument. In the same way, the fact that many people repeat false information makes it harder for us to consider the possibility that the information is not true. Because of authority bias, this effect is stronger if the people repeating the bad argument or the false information are experts in the field in question.

A bias related to this is the availability cascade, which occurs when a collective belief gains more and more acceptance through its increasing repetition in public discourse, even if it is not plausible. The longer the belief is repeated, the harder it is to challenge it.

All of this seems to be at least part of the explanation of why people, including experts in academia, rarely analyze attempts to justify speciesism and arguments against the proposal to help wild animals with the same rigor with which they analyze arguments in the opposite direction.