James Tilly Matthews illustrated this picture of a machine called an "air loom", which he believed was being used to torture him and others for political purposes. The modern definition and Jaspers' original criteria have been criticised, as counter-examples can be shown for every defining feature. Studies on psychiatric patients show that<unk> s vary in intensity and conviction over time, which suggests that certainty and incorrigibility are not necessary components of a<unk> al belief.<unk> s do not necessarily have to be false or 'incorrect inferences about external reality'. Some religious or spiritual beliefs by their nature may not be falsifiable, and hence cannot be described as false or incorrect, no matter whether the person holding these beliefs was diagnosed as<unk> al or not. In other situations the<unk>  may turn out to be true belief. For example, in<unk> al jealousy, where a person believes that their partner is being unfaithful (and may even follow them into the bathroom believing them to be seeing their lover even during the briefest of partings), it may actually be true that the partner is having sexual relations with another person. In this case, the<unk>  does not cease to be a<unk>  because the content later turns out to be verified as true or the partner actually chose to engage in the behavior of which they were being accused. In other cases, the belief may be mistakenly assumed to be false by a doctor or psychiatrist assessing it, just because it seems to be unlikely, bizarre or held with excessive conviction. Psychiatrists rarely have the time or resources to check the validity of a person's claims leading to some true beliefs to be erroneously classified as<unk> al. This is known as the Martha Mitchell effect, after the wife of the attorney general who alleged that illegal activity was taking place in the White House. At the time, her claims were thought to be signs of mental illness, and only after the Watergate scandal broke was she proved right (and hence sane). Similar factors have led to criticisms of Jaspers' definition of true<unk> s as being ultimately 'un-understandable'. Critics (such as R. D. Laing) have argued that this leads to the diagnosis of<unk> s being based on the subjective understanding of a particular psychiatrist, who may not have access to all the information that might make a belief otherwise interpretable. R. D. Laing's hypothesis has been applied to some forms of projective therapy to "fix" a<unk> al system so that it cannot be altered by the patient. Psychiatric researchers at Yale University, Ohio State University and the Community Mental Health Center of Middle Georgia have used novels and motion picture films as the focus. Texts, plots and cinematography are discussed and the<unk> s approached tangentially. This use of fiction to decrease the malleability of a<unk>  was employed in a joint project by science-fiction author Philip Jose Farmer and Yale psychiatrist A. James Giannini. They wrote the novel Red Orc's Rage, which, recursively, deals with<unk> al adolescents who are treated with a form of projective therapy. In this novel's fictional setting other novels written by Farmer are discussed and the characters are symbolically integrated into the<unk> s of fictional patients. This particular novel was then applied to real-life clinical settings. Another difficulty with the diagnosis of<unk> s is that almost all of these features can be found in "normal" beliefs. Many religious beliefs hold exactly the same features, yet are not universally considered<unk> al. For instance, if a person was holding a true belief then they will of course persist with it. This can cause the disorder to be misdiagnosed by psychiatrists. These factors have led the psychiatrist Anthony David to note that "there is no acceptable (rather than accepted) definition of a<unk> ." In practice, psychiatrists tend to diagnose a belief as<unk> al if it is either patently bizarre, causing significant distress, or excessively pre-occupying the patient, especially if the person is subsequently unswayed in belief by counter-evidence or reasonable arguments. Joseph Pierre, M.D. states that one factor that helps differentiate<unk> s from other kinds of beliefs is that anomalous subjective experiences are often used to justify<unk> al beliefs. While idiosyncratic and self-referential content often make<unk> s impossible to share with others, Dr. Pierre suggests that it may be more helpful to emphasize the level of conviction, preoccupation, and extension of a belief rather than the content of the belief when considering whether a belief is<unk> al. It is important to distinguish true<unk> s from other symptoms such as anxiety, fear, or paranoia. To diagnose<unk> s a mental state examination may be used. This test includes appearance, mood, affect, behavior, rate and continuity of speech, evidence of hallucinations or abnormal beliefs, thought content, orientation to time, place and person, attention and concentration, insight and judgment, as well as short-term memory. Johnson-Laird suggests that<unk> s may be viewed as the natural consequence of failure to distinguish conceptual relevance. That is, irrelevant information would be framed as disconnected experiences, then it is taken to be relevant in a manner that suggests false causal connections. Furthermore, relevant information would be ignored as counterexamples. Definition Although non-specific concepts of madness have been around for several thousand years, the psychiatrist and philosopher Karl Jaspers was the first to define the four main criteria for a belief to be considered<unk> al in his 1913 book General Psychopathology. These criteria are: * certainty (held with absolute conviction) * incorrigibility (not changeable by compelling counterargument or proof to the contrary) * impossibility or falsity of content (implausible, bizarre, or patently untrue) *not amenable to understanding (i.e., belief cannot be explained psychologically) Furthermore, when beliefs involve value judgments, only those which cannot be proven true are considered<unk> s. For example: a man claiming that he flew into the Sun and flew back home. This would be considered a<unk> , unless he were speaking figuratively, or if the belief had a cultural or religious source. Only the first three criteria remain cornerstornes of the current definition of a<unk>  in the DSM-5. Robert Trivers writes that<unk>  is a discrepancy in relation to objective reality, but with a firm conviction in reality of<unk> al ideas, which is manifested in the "affective basis of<unk> ."
Delusion
Distress 
Morbid love
Perseveration
Obsessive love
Automatism 
Mindfulness
Intrusive thought