Aristotle is generally credited with developing the basics of the system of rhetoric that "thereafter served as its touchstone", influencing the development of rhetorical theory from ancient through modern times. The "Rhetoric" is regarded by most rhetoricians as "the most important single work on persuasion ever written." Gross and Walzer concur, indicating that, just as Alfred North Whitehead considered all Western philosophy a footnote to Plato, "all subsequent rhetorical theory is but a series of responses to issues raised" by Aristotle's "Rhetoric". This is largely a reflection of disciplinary divisions, dating back to Peter Ramus' attacks on Aristotelian rhetoric in the late 16th century and continuing to the present.