On Passions (Greek: Περὶ παθῶν; Peri pathōn), also translated as On Emotions or On Affections, is a work by the Greek Stoic philosopher Chrysippus dating from the 3rd-century BCE. The book has not survived intact, but around seventy fragments from the work survive in a polemic written against it in the 2nd-century CE by the philosopher-physician Galen. In addition Cicero summarises substantial portions of the work in his 1st-century BCE work Tusculan Disputations. On Passions consisted of four books; of which the first three discussed the Stoic theory of emotions and the fourth book discussed therapy and had a separate title—Therapeutics. Most surviving quotations come from Books 1 and 4, although Galen also provides an account of Book 2 drawn from the 1st-century BCE Stoic philosopher Posidonius. Little or nothing is known about Book 3. The Stoics believed that the mind was rational, and that emotions involve judgements. The Stoic passions are emotions such as fear, anger, and desire which cause suffering. In his On Passions, Chrysippus explained how the passions arise from the mistaken opinions of what is good and bad. They are excessive and disobedient to reason, which Chrysippus compared to a runner who is out-of-control. A person in the grip of passion has rejected reason, and therapy is a medical art needed to treat the mind. The treatment outlined by Chrysippus was mostly preventative, demonstrating by theory that the passions are neither natural or necessary, and showing through practice that the mind can be trained to reject them. Source: Wikipedia (en)