Among American epistemologists, Gettier (1963) have questioned the "justified true belief" definition, and challenged the "sophists" of their time.
Delusion arises when the truth value of the form is clearly nil. Berrios has challenged the view that delusions are genuine beliefs and instead labels them as "empty speech acts," where affected persons are motivated to express false or bizarre belief statements due to an underlying psychological disturbance.
(for example in the Diagnostic and Statistical Manual of Mental Disorders). However, the majority of mental health professionals and researchers treat delusions as if they were genuine beliefs.
In epistemology, philosophers use the term "belief" to refer to personal attitudes associated with true or false ideas and concepts.
However, "belief" does not require active introspection and circumspection.
The tendency to translate from belief (here: doxa - common opinion) to knowledge (here: episteme), which Plato (e.g.