To what extent is the use of rhetorical figures in philosophical writing, such as metaphors and analogies, the mark of a weakness on the part of the author? Can we sort out different styles of philosophizing, such as analytic and continental, based on their use of rhetorical devices?
Rhetoric in Ancient Greek Philosophy
Ancient Greek philosophy abounds of remarkable usages of rhetorical figures. They are found in most of the key passages of Plato’s philosophy. Among the chief examples are the allegory of the cave, the metaphor of the sun, and the analogy of the divided line, all appearing in The Republic. Here are three examples: each of them aims at expressing the imperfection of the world as we know it through the senses in contrast with the truth that can be ascertained by those that contemplate matters through the light of pure reason. Still in The Republic we find the myth of Er, which illustrates Plato’s conception of the soul as immortal.
It is less easy to assess the role of rhetoric in the work of Aristotle, since we do not read his writings for a wider public. On the other hand, the fact that he dedicated a whole treatise to rhetoric shows the importance he accorded to the subject. The first recorded footsteps of Western philosophy, moreover, are in verses: Parmenides wrote a poem on nature, and so it seems did most of his contemporary colleagues. Needless to say, the medieval discourse on philosophical theology is filled with analogies and metaphors, used to express the perfection of god, the nature of the soul or the intellect, and the relationship between the spirit and the body.
But even Descartes, the man who started modern philosophy, made wide use of rhetorical figures in key passages. The barebones of the Meditations rely on the fact that certain truths are evident by natural light: nowhere will you find an explanation of what he meant with such an expression. That we are imperfect and finite while having the idea of perfection and infinity is true by natural light and, hence, cannot be contested: without this assumption Descartes could not prove that God exists in the third meditation. Where rhetoric starts becoming scarce is with Kant and the subsequent German philosophical and logical tradition that ensued from it. Clearly, for authors such as Hegel, Schelling, Nietzsche, or Kierkegaard metaphors, analogies, and other rhetorical figures were fundamental to express the deepest philosophical insights. But some people started being of a different advice, mostly because of the rise in popularity of everything scientific within the public opinion.
Thought Experiments and the Quest for a Scientific Dress
Thus, when analytic philosophy arouse at the end of eighteen hundreds, modeled after the most successful sciences of the time – physics and mathematics – its goal was to be perceived as void of rhetorical appeal. If analytic philosophers have tried to avoid usage of metaphors and analogies, they have repeatedly employed thought experiments. Hilary Putnam’s twin earth experiment and the brain in a vat scenario (which inspired the movie The Matrix and revived contemporary skepticism) are chief examples of the attitude. Galileo and Newton’s laws of motion are formulated against the backdrop of some ideal scenarios; so are the most sophisticated philosophical theories of our days. Philosophy now seemed to have found its scientific dress
As the decades have gone by, the dress is getting thinner and thinner. The reason is simple: physical, chemical or biological theorizing is at least partially dependable on experimental confirmation; but there is no such thing for philosophical theorizing. This fact has rendered the latter even the more abstruse to the laymen and probably contributed to the marginalization of philosophy. Moreover, as Mary Hesse has convincingly shown in a number of studies dating as back as the late fifties and early seventies, scientific reasoning crucially relies on analogies and metaphors, for example when we understand a theory of microphysics in terms of macroscopic models. And, if we read philosophy closely, we'll find plenty of rhetoric too.
In conclusion, despite the efforts to weed out the use of rhetoric from philosophy, it seems that our deepest thoughts are best expressed with the aid of powerful images.
