Philosophical Delusion and its Therapy provides new foundations and methods for the revolutionary project of philosophical therapy pioneered by Ludwig Wittgenstein. With the help of concepts adapted from cognitive linguistics and cognitive psychology, the book analyses how philosophical reflection is shaped by pictures and metaphors we are not aware of employing and are prone to misapply. Through innovative case-studies on the genesis of classical problems about the mind and perception, and on thinkers including Locke, Berkeley and Ayer, the book demonstrates how such autonomous habits of thought systematically generate unsound intuitions and philosophical delusions.