The supernatural was an intellectual preoccupation for Scottish philosopher, theologian and later President of Princeton University James McCosh (1811–94), who attacked John Stuart Mill's 1843 System of Logic (also reissued in this series) for not addressing the issue of the supernatural. In this work, published in 1862, McCosh gives his full attention to the question, saying his aim was to 'disentangle the confusion' about the relationship between the natural and supernatural. He defines the supernatural as anything acting outside the sphere of nature. The first part of the book examines the natural world's relationship to the supernatural through a discussion of the laws and principles that are thought to govern nature. The second part takes the opposite approach, considering the relationship of the supernatural to the natural by examining instances within Christian literature, such as prophecy and miracles, which are difficult to explain.