..... . Hume attempts to identify the principles or mechanisms that underlie human mental activity. The human mind is the object of his research, just as the external world is the object of much scientific research. Especially in his "causal theory" we can see evidence of this ambition. In order to understand how people form the idea of causation, he investigates the contents and sources of causality. Finally, he raises three essentials: contiguity, priority and necessary connection.
.. ... Hume thinks the necessary connection is more important than the other two, so he discusses the source of the idea of necessary connection at great length. He denies that intuition or reasoning is the source. He argues that experience is the source. This part of the discussion, however, has some flaws and there are two different interpretations of his argument: naturalism and skepticism. This thesis attempts to adjudicate between these interpretations. Herein it is argued that skepticism subverts the goal of causal theory that Hume established and the naturalism is more consistent with Hume’s intentions.
Keywords：impression, idea, causality, necessary connection, belief, naturalism, skepticism