Delusional people are people saying very bizarre things like they are dead, their spouse is a robot, the TV star is talking to them, they are possessed by the devil, aliens are following them, and so on. Even though we know that they are not identical, terms like "delusion" and "mental illness" are often used as synonyms in ordinary language. This comes from what psychopathology tradition handed down: delusion is the key psychopathological phenomenon, although essentially un-understandable (Jaspers, 1959). In her book Delusion

HighlightsThere are a number of controversial questions regarding the nature and causes of unrealistic optimism.We argue that unrealistically optimistic cognitions should be considered beliefs rather than desires or hopes.Optimistically biased beliefs are frequently false but establishing falsity in individual cases is difficult and sometimes impossible.Optimistically biased beliefs are epistemically irrational because they are unwarranted and their responsiveness to counter-evidence is limited.

Delusions are defined as irrational beliefs that compromise good functioning. However, in the empirical literature, delusions have been found to have some psychological benefits. One proposal is that some delusions defuse negative emotions and protect one from low self-esteem by allowing motivational influences on belief formation. In this paper I focus on delusions that have been construed as playing a defensive function (motivated delusions) and argue that some of their psychological benefits can convert into epistemic ones. Notwithstanding their epistemic costs, motivated delusions also have potential epistemic benefits for agents who have faced adversities, undergone physical or psychological trauma, or are subject to negative emotions and low self-esteem. To account for the epistemic status of motivated delusions, costly and beneficial at the same time, I introduce the notion of epistemic innocence. A delusion is epistemically innocent when adopting it delivers a significant epistemic benefit, and the benefit could not be attained if the delusion were not adopted. The analysis leads to a novel account of the status of delusions by inviting a reflection on the relationship between psychological and epistemic benefits.

Philosophers are interested in the phenomenon of thought insertion because it challenges the common assumption that one can ascribe to oneself the thoughts that one can access first-personally. In the standard philosophical analysis of thought insertion, the subject owns the 'inserted' thought but lacks a sense of agency towards it. In this paper we want to provide an alternative analysis of the condition, according to which subjects typically lack both ownership and authorship of the 'inserted' thoughts. We argue that by appealing to a failure of ownership and authorship we can describe more accurately the phenomenology of thought insertion, and distinguish it from that of non-delusional beliefs that have not been deliberated about, and of other delusions of passivity. We can also start developing a more psychologically realistic account of the relation between intentionality, rationality and self knowledge in normal and abnormal cognition.

Is it ethically permissible to use deception in psychological experiments? We argue that, provided some requirements are satisfied, it is possible to use deceptive methods without producing significant harm to research participants and without any significant violation of their autonomy. We also argue that methodological deception is at least at the moment the only effective means by which one can acquire morally significant information about certain behavioral tendencies. Individuals in general, and research participants in particular, gain self-knowledge which can help them improve their autonomous decision-making. The community gains collective self-knowledge that, once shared, can play a role in shaping education, informing policies and in general creating a more efficient and just society.