David Hume has had a massive influence on the free will debate. Much of this influence is attributed to the chapter 'Liberty and Necessity' in his book 'An Enquiry into Human Understanding' which is the focus of this essay. What we see overall is Hume forwarding a new theory called compatibalism, in which he attempts to combine human free will or 'liberty' (choice , responsibility, morality) with causality or 'necessity' (all things have a cause, cause always preceeds or comes with an effect) by re-defining what we mean by these terms. Essentially Hume makes liberty and necessity compatible with one another, when previously they were not. Hume concludes by arguing that they have always been compatible, people only thought they were not compatible because they had confused ideas about what liberty and necessity actually meant. Ultimately Hume's compatibalist theory is original in its attempt to re-define and unite liberty and necessity, while at the same time maintaining that morality is dependent upon a compatibalist argument and that ideas about religion and God are illogical.
             In Hume's time of writing there were two major theories in the free will debate. They are now commonly referred to as Hard determinism and Libertarianism. Hard determinism argues that all events are both causes and effects, that the universe is governed by cause and effect so rigorously that everything that happens had to happen and could not have happened any other way. For example, an effect (a match lighting) happens because of a cause (the match being struck). Often what is referred to is a causal circumstance, because it is necessary to have more than one cause or set of conditions for an effect to happen, (for a match to light it not only has to be struck but there has to be oxygen present and the match has to be dry etc.). This is simple cause and effect. When Hard determinism is taken to be how the entire world (and universe) operates, it has importan...