Why footnote?

"How green are you? Look at your sloppy footnotes." Professor Kelly irriated.
"Why footnote?" Student Walsh grumbled.

I used to distribute rules and examples of footnote format to students, major and non-major, at the beginning of every course. A curious question indeed for laymen (like freshmen), and practitioners too. Laymen see it as an unncessary evil, practitioner see it as a necessary evil. The following excerpts are from Anthony Grafton, The Footnote: A Curious History. Harvard: Harvard University Press, 1997, which I have partly read recently.

"In the modern world - as manuals for writers of dissertations explain - historians perform two complementary tasks. They must examine all the sources relevant to the soulution of a problem and construct a new narrative or argument from them. The footnote proves that both tasks have been carried out. It identifies both the primary evidence that guarantees the story's novelty in substance and the secondary works that do not undermine its novelty in form and thesis. By doing so, moreover, it identifies the work of history in question as the creation of a professional." (p. 4-5)

"students move from craft to industrial styles of footnote production, peppering each chapter with a hundred or more references to show that they have put in hours of hard work in arhcive and library." (p. 5)

"the production of footnotes sometimes resembles less the skilled work of a professional carrying out a precise function to a higher and than the offhand production and disposal of waste products." (p. 6)

"All over the modern histtorical world, articles begin with an industrialized civilization's equivalent to the ancient invocation of the Muse: a long note in which the author thanks teachers, friends, and colleagues. Prefatory notes evoke a Republic of Letters - or at least an academic support group - in which the writer claims memebership." (p. 7)

"Long lists of earlier books and articles and strings of coded reference to unpublished documents supposedly prove the solidity of the author's research by rendering an account of the sources used." (p. 7)

"Few readers will have the tenacity to check the story for its accuracy, and most will assume that the elegant pickpocket, not the disheveled victim, has told the truth." (p. 14)

"The footnote demands attention for other reasons as well: not only as a general part of the practice of science and scholarship, but also as an object of keen nostalgia and a subject of sharp debate." (p. 14)

"A hundred years ago, most historians would have made a simple distinction: the text persuades, the notes prove." (p. 15)

"In fact, of course, no one can ever exhaust the range of sources relevant to an important problem - much less quote all of them in a note. In practice, moreover, every annotator rearranges materials to prove a point, interprets them in an individual way, and omits those that do not meet a necessarily personal standard of relevance." (p. 16)