The ethics of belief concerns the study of those rules or guidelines (‘norms’) that apply to people adopting or maintaining beliefs—that is, the ethics of our epistemic behaviour. For instance, many think that the fundamental norm is not to believe something for which there is no sufficient evidence. In that context, we can ask whether someone is responsible for forming a belief for which she does not have sufficient evidence, and whether she should be blamed for it. This is a deontological approach to the ethics of belief.

Alternatively, the fundamental norm could be to maximize epistemic value when adopting new beliefs, where epistemic value can be thought of in terms of the ratio of true to false beliefs, epistemic utility (how useful the belief is), or epistemic virtue (to what extent agents exhibit good character, for instance, intellectual honesty or humility). Then, we would focus on the consequences of an agent adopting certain beliefs or following certain rules for the adoption of beliefs. This is a consequentialist approach to the ethics of belief.

Our suggestion is that no matter which approach we choose, it is not obvious that delusions are ethically problematic beliefs. The term ‘delusion’ refers to a clinical phenomenon, and in particular to a symptom of schizophrenia, delusional disorders, dementia, amnesia, and other psychiatric disorders. In the most recent version of the Diagnostic and Statistical Manual of Mental Disorders (commonly referred to as the DSM-5), delusion is defined as a false belief that is firmly held despite what almost everyone else believes, and despite what constitutes obvious proof or evidence to the contrary. The definition has been challenged on various grounds, but it remains a useful diagnostic tool for clinicians.

Examples of delusions are persecution, where the person reports that other people are hostile and intend to cause her harm, and jealousy, where the person reports that her romantic partner is being unfaithful to her. More bizarre delusions include mirrored-self misidentification, where the person reports that there is a stranger in the mirror, or the Cotard delusion, where the person reports that she is dead or disembodied.

Why do we claim that people should not be held responsible or blameworthy for having delusions? First, in the context in which delusions are formed, people’s ability to believe otherwise is significantly compromised due to reasoning impairments, biases, and motivational factors. For instance, people with delusions tend to jump to conclusions, coming to a set judgement about the likelihood of an event without having considered carefully the evidence at their disposal. From a deontological point of view, impairments, biases, and motivational factors prevent such people from adopting an alternative belief to the delusional one, and from recognizing the epistemic shortcomings of their delusions.

Second, delusions have obvious epistemic faults, being often wildly implausible and irresponsive to counter-evidence. But some delusions enable agents to manage negative feelings that could become overwhelming and provide an explanation for anomalous hypersalient experience, putting an end to a state of anxious expectation that undermines attention and concentration. Some also argue that delusions can help people resume learning that was previously disrupted by the effects of anomalous experience on their model of the world. As counterintuitive as it may sound, the adoption of a delusional hypothesis may help avoid bad epistemic consequences and it can enable people to engage with the physical and social environment surrounding them at a critical time.

Delusions can be an example of epistemically innocent cognitions. If at the time of the person adopting the delusional beliefs, the delusion prevents a serious epistemic harm from occurring, and no alternative beliefs are available to the person, then such delusions are not ethically problematic and what we have is a case of epistemic innocence.

The notion of epistemic innocence can make a number of positive contributions to the general debate on the ethics of belief: it points to the fact that the scope of epistemic evaluation is wider than the enterprise of establishing whether a belief is justified by evidence; it forges connections between deontological and consequentialist approaches to the ethics of belief; and it emphasizes the need to take into account contextual factors in the practice of belief evaluation.