In modern philosophical use, the term phenomena means things as they are experienced through the senses and processed by the mind as distinct from things in and of themselves (noumena). In his inaugural dissertation, titled On the Form and Principles of the Sensible and Intelligible World, Immanuel Kant (1770) theorizes that the human mind is restricted to the logical world and thus can only interpret and understand occurrences according to their physical appearances. He wrote that humans could infer only as much as their senses allowed, but not experience the actual object itself. Thus, the term phenomenon refers to any incident deserving of inquiry and investigation, especially processes and events which are particularly unusual or of distinctive importance.