The art of rhetoric, or persuasive public speaking, was brought to perfection in classical Athens. During the fifth and fourth centuries B.C.E., rhetoric came under the scrutiny of the philosophers. While Plato dismissed public speaking as mere hackwork devoid of a rational basis, Aristotle defended it as a true art. In his great work, Treatise on Rhetoric, which laid the foundations of philosophical rhetoric, Aristotle deals at length with the processes of argument and with style, including rhythm and meter. For Aristotle, rhetoric is a brand of the art of reasoning; its function he defends not as mere persuasion, but as "the observing of all of the available means of persuasion."