I offer a read ing of Dostoevsky's eth ical philosophy, Jrawing on his fiction and non-fiction work. I argue that coJ1cepts of human oalure and flouri shing are central to Dostoevsky's ethical thought ~d underpin his argum entative strategy in the fiction. ln Part I, l set oul Dostoevsky's ethical philosophy. Dostoevsky rejects the role of reason in ethics and insists that moral action is motivated by spontaneous moral feelin gs . The goal of ethical activity is to develop the se spontaneous feelings and to perfect oneself in the im age of the ideally virtuous agent, Christ. To strive to do so is to flo urish. The i<.lea.l of hum an pe,tect ion is present in un reali sed form in hum an natu re, a.11d self-perfection is n natural process . The process is interrup ted, however. by the desire for autonomy, which undermines one's inner ham10 ny , creating self-des tructive tend encies alongside the natural tendency to self-perfection. This loss of inner harm ony represents t.he opposite of human flourishin g: moral disease. These ideas are apparent in Dostoevsky's views on freedom, res pons ibili y, and the origin of sin. AL the end of Part I, l di scuss Dos toevsky's fict ion al characters in the light of hi s ethi cal thou ght. I sugges t his negative ch :Hacters can be read as experiments des igned to estab lish the conditions Gf hu:11 an fl ourishing. ln Part II , r con si der Dos toevsky's ' cJ011bkd' characters as experiment � . These character ' ar unable Lo es tabli sh the truth abou t their own motivation. a predicament brought abo ut by the ridicule of others . Dosloevsky's ex perim ent assumes that one's confidence in one's account of one's own motivation is affected by Lhe attitudes of others to that account. This as sumption , which is at least pl ausible; is central to Dostoevsky portrayals of interactions between characters. It leads to conclusions that are consonant with his ethical thought - though there are also points of tension.