A.O. Lovejoy begins his introduction to The Great Chain of Being by attempting to explain what is meant by the study of the history of ideas. In doing this, he is referring to "something at once more specific and less general than the history of philosophy." The key difference lies in the units of which each is made. The history of philosophy contains concepts and movements that must be broken down into smaller fragments, or unit ideas. According to Lovejoy, the history of ideas is comparable to analytical chemistry; the primary focus of the historian is to separate the individual units from the greater picture or, in terms of analytical chemistry, to isolate them into their component elements. The historian's next endeavor is to trace a single unit idea through all the provinces of history. The idea of "Good," for example, for any "Platonist," is personified by...