The objective of this doctoral dissertation is to interpret the explanation of akrasia that the Dutch philosopher Benedictus Spinoza (1632-1677) gives in his work The Ethics. One is said to act acratically when one intentionally performs an action that one judges to be worse than another action which one believes one might perform instead. In order to interpret Spinoza’s explanation of akrasia, a large part of this dissertation investigates Spinoza’s theory of emotion. The first chapter is introductory and outlines Spinoza’s (...) categorisation of mental states and his conception of the relation between the mind and the body. The second chapter deals with Spinoza’s epistemology and the relation between cognitive mental states and states of the brain. The third chapter argues that Spinoza holds that emotions are non-cognitive mental states that are caused by cognitive mental states. The fourth chapter interprets Spinoza’s discussion of the emotions of Joy and Sadness insofar as they are mental states. The fifth chapter suggests that when Spinoza says that the power of our body is increased or decreased when we are joyful or sad, he means that when we are joyful or sad then, at the same time, our heart and perhaps the organs of our digestive system are affected in such a way that our bodily health is increased or decreased. The sixth chapter points to three problems that concern Spinoza’s definitions of the psychophysical states of pleasure, pain, cheerfulness and melancholy, and offers slightly altered definitions of these states. The seventh chapter interprets the various aspects of Spinoza’s conception of the emotion of Desire, both insofar as it is a state of the mind and insofar it is a state of the body, as well as the relation between the emotion of Desire and man’s striving for self-preservation. The eighth chapter discusses what Spinoza writes on the strength of emotions and the way in which we make value judgments in order to finally interpret why it is, according to Spinoza, that ‘we so often see the better for ourselves but follow the worse’. (shrink)