If you are interested in the philosophical discussion surrounding the authenticity of period instrument performance practice, I recommend you read the following book:

AUTHENTICITIES -- Philisophical Reflections on Musical Performance
Written by Peter Kivy
Published by Cornell University Press - Ithaca and London
Copyright 1995.
299 pages
ISBN 0-8014-3046-1

Inside Jacket Cover:

"How are we to assess the current popularity of period instruments and early-music performance? For musicians and audiences alike, the "historical authenticity" movement has increasingly influenced the performance of classical music. It has given us, claims Peter Kivy, 'new and rewarding ways of listening to our musical repertory (as well as silly, vulgar, and unrewarding ones).' He believes that theory now overrules the ear in arguing for and justifying particular aesthetic decisions.

"In his customary engaging style, Kivy here mounts a philosophical inquiry into the desirability of using or re-creating historical practices in performance. 'Authenticity has become so widely accepted, ' he writes, 'that why it should be accepted has become an unasked, indeed a forgotten question among the converted.' In 'How to Be Authentic,' the first section of his book, he examines four different kinds of authenticty; in the second part, 'Why to Be Authentic,' he suggests how to evaluate them. Discussing issues that he cares about passionately, Kivy provides ammunition for both camps--those who follow authentic performance practice and those who do not.

"It is his (the author's) hope that his book provides the groundwork for dialogue between musicians and philosophers. 'I look forward to that,' he says, 'and to being, when it comes, in the thick of things."

PETER KIVY is Professor of Philosphy at Rutgers University. His previous books include Music Alone: Philosophical Reflections on the Purely Musical Experience and Sound and Semblance: Reflections on Musical Representation, also from Cornell.