David Hume was a Scottish philosopher, historian, economist and essayist who is known for his highly influential system of empiricism, philosophical scepticism and metaphysical naturalism. Beginning with A Treatise of Human Nature (1739–40), Hume strove to create a naturalistic science of man that examined the psychological basis of human nature. Hume followed John Locke in rejecting the existence of innate ideas, concluding that all human knowledge derives solely from experience; this places him amongst such empiricists as Francis Bacon, Thomas Hobbes, Locke and George Berkeley.
Hume argued that inductive reasoning and belief in causality cannot be justified rationally; instead, they result from custom and mental habit. People never actually perceive that one event causes another but only experience the "constant conjunction" of events.