The problem of determining whether epistemically irrational beliefs can contribute to psychological or biological adaptiveness has been extensively explored. However, a similar question has until recently remained unanswered: Can a belief that is epistemically irrational nevertheless contribute to the pursuit and attainment of epistemic goals? Or, put differently, can epistemically irrational beliefs have a positive impact on epistemic performance?
In her book, The Epistemic Innocence of Irrational Beliefs, Lisa Bortolotti reviews a body of psychological, psychiatric and philosophical evidence that suggests a positive answer to this question. She argues that at least some epistemically irrational beliefs can be useful for promoting epistemic agency.
Epistemically irrational beliefs are defined as beliefs that are either poorly grounded in relevant evidence or resistant to best available counterevidence—including cases where they exhibit logical incoherence or empirical implausibility.
In the existing literature on this subject, irrational beliefs are rarely viewed charitably in light of their epistemic shortcomings. However, Bortolotti challenges this standard picture and makes a compelling case that epistemic irrationality should, in some cases, be tolerated—if it leads to otherwise unattainable improvements to epistemic functionality or psychological well-being. If an agent’s overall epistemic or psychological condition benefits from holding such beliefs, then they should be viewed as being epistemically innocent.
For a belief to qualify as epistemically innocent, however, another condition must also be met: better epistemic alternatives must either be nonexistent or simply unavailable to the subject. This means that an irrational belief should only be rejected if a rational alternative exists that provides comparable epistemic benefits.
At this point, it is useful to illustrate Bortolotti’s argument with a concrete example. Consider, for instance, distorted memory beliefs in patients with amnesia or dementia—such cases are discussed in various parts of the book. These beliefs, though inaccurate or incomplete, help individuals keep certain key bits of autobiographical information intact, thus maintaining a coherent sense of self. Moreover, these beliefs can aid in emotional regulation and social communication with peers, leading to a richer, more stable, and well-integrated understanding of one’s place in the world.
The book is divided into seven chapters, each (apart from the introductory and the final, concluding chapter) dedicated to an exploration of a specific type of irrational belief. After discussing distorted memory beliefs in the second chapter, the following chapters examine confabulated explanations, elaborated and motivated delusional beliefs, and optimistically biased beliefs.
Each chapter begins with introductory remarks and conceptual groundwork, followed by a detailed argument demonstrating that the belief in question—despite being irrational—offers epistemic benefits. This is where the book really shines. Bortolotti presents a wealth of empirical and conceptual evidence, showing that various forms of epistemic irrationality have adaptive features that either directly improve epistemic functionality, or indirectly support it through emotional, psychological or social well-being. This idea serves as the central thread that weaves together various topics discussed in the book, even though the argument develops in important aspects to accommodate the specifics of each case.
For example, consider optimistically biased beliefs. A person with an overly optimistic view of their ability—whether in mathematics, language learning, or another skill—may demonstrate higher motivation and resilience when faced with setbacks. Even though their self-assessment is objectively inaccurate, it opens up new epistemic possibilities that would be inaccessible from a more modest (yet accurate) perception of their abilities. On the other hand, in psychiatric conditions such as schizophrenia, irrational beliefs often emerge in response to deeply distressing cognitive or affective symptoms. Take the example of the Cotard delusion, in which a person believes they are dead or do not exist. Bortolotti argues that this belief, while highly disruptive, can also be epistemically beneficial if it provides the best explanation available for an otherwise anomalous and deeply puzzling experience. If a person says that she cannot feel anything and that she believes she is dead, we should recognize this as an attempt to structure an incomprehensible experience, rather than dismissing it as mere irrationality. If a more rational explanation were less effective in preserving psychological stability, then the irrational belief—while flawed—might still be the more epistemically functional one.
One of Bortolotti’s most important contributions to the debate on epistemic irrationality is her challenge to the traditional view that irrational beliefs are deviations from epistemic norms (truth, justifiability, coherence, etc.), and should therefore be discarded as epistemically worthless. After reading her book, it becomes difficult to maintain the conviction that irrational beliefs are intrinsically defective. Her argument encourages deeper and broader exploration of the boundary between rational and irrational beliefs—one that moves beyond the standard, conventional distinctions.
Beyond its theoretical implications, Bortolotti’s book also has practical significance. Her account challenges systematic exclusion of psychiatric patients, particularly those with schizophrenia. By recognizing their epistemically innocent beliefs as strategies for coping with abnormal experiences, she argues that their perspective deserves serious attention, rather than outright dismissal. This has direct implications for psychiatric practice, offering a framework that acknowledges hermeneutic injustice, while also building a conceptual bridge between clinical and non-clinical, everyday occurrences of irrational behavior, which has an important role in cultivating a more balanced approach to this important area of research.
In The Epistemic Innocence of Irrational Beliefs Lisa Bortolotti invites us to reconsider what it means for a belief to be epistemically valuable. It offers a powerful challenge to traditional epistemology that sees irrational beliefs as serving no epistemic functions at all. This impressive book expands our understanding of rationality, mental health and epistemic agency, while simultaneously serving as an appeal to a more compassionate and sympathetic treatment of people under psychiatric care. As such, it is an essential reading for anyone interested in epistemology, philosophy of mind, philosophy of psychiatry, or ethics.