James mill believed that the human mind was totally passive. He felt that the mind was a machine functioning in the same way as a clock, acting upon external stimuli. His most important work and contribution to psychology is his book, Analysis of the phenomena of the Human Mind, written in 1829. Mill states that the mind must be studied through its reduction or analysis into elementary components. Mill believed that ideas and sensations are only certain kinds of mental process. He felt that ideas result as a process of sensations that have occurred at the same time in a certain order. Thus, James Mill was considered a British empiricist, focusing on the primary role of sensation processes and the relationship between conscious processes and association. John Stuart Mill, Who believed in Mental Chemistry, was the son of James Mill.