sentences:  To supply but a single example, the oft-quoted aphorism of Santayana's, "Those who cannot remember the past are condemned to repeat it," may be found on p. 284 of "Reason in Common Sense".In 1951, near the end of his life, Santayana engaged himself in the weighty task of producing a one-volume abridgment of "The Life of Reason" at the urging of his editor at Scribner's, with the assistance of his friend and student, Daniel Cory.As Cory writes in the volume's preface, in addition to excising prolixities and redundancies from the book, "[a] sustained effort was made to dispel those early mists of idealism from the realistic body of his philosophy, and to make clear to the reader that our "idea" of a natural world can never be "that world itself"."