David Hume 
A Treatise of Human Nature 

David Hume (/ˈhjuːm/; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) was a Scottish philosopher, historian, economist, and essayist, who is best known today for his highly influential system of radical philosophical empiricism, skepticism, and naturalism. Hume’s empiricist approach to philosophy places him with John Locke, George Berkeley, Francis Bacon, and Thomas Hobbes as a British Empiricist. Beginning with his A Treatise of Human Nature (1739), Hume strove to create a total naturalistic science of man that examined the psychological basis of human nature. Against rationalists, Hume held that passion rather than reason governs human behaviour. He argued against the existence of innate ideas, postulating that humans can have knowledge only of the objects of experience, and the relations of ideas, calling the rest ’nothing but sophistry and illusion‘, a dichotomy later given the name Hume’s fork. He also argued that inductive reasoning, and therefore causality, cannot, ultimately, be justified rationally: our belief in causality and induction instead results from custom, habit, and experience of ‚Constant conjunction‘ rather than logic.[4] He denied that humans have an actual conception of the self, positing that we experience only a bundle of sensations, and that the self is nothing more than this bundle of causally-connected perceptions. Hume’s compatibilist theory of free will takes causal determinism as fully compatible with human freedom, and has proved extremely influential on subsequent moral philosophy. Hume was also a sentimentalist who held that ethics are based on emotion or sentiment rather than abstract moral principle, famously proclaiming that ‚Reason Is and Ought Only to Be the Slave of the Passions‘. Contemporary scholars view Hume’s moral theory as a unique attempt to synthesize the modern sentimentalist moral tradition to which Hume belonged, with the virtue ethics tradition of ancient philosophy, with which Hume concurred in regarding traits of character, rather than acts or their consequences, as ultimately the proper objects of moral evaluation. Hume’s moral theory maintained an early commitment to naturalistic explanations of moral phenomena, and is usually taken to have first clearly expounded the is–ought problem, or the idea that a statement of fact alone can never give rise to a normative conclusion of what ought to be done (font: Wikipedia)