Interesting article here – https://people.sunyit.edu/~harrell/Pepper/pep_metaphor.htm
Metaphor in Philosophy
by Stephen Pepper
Reprinted from The Journal of Mind and Behavior, vol. 3, nos. 3 and 4, summer/autumn, 1982, a special issue of that journal devoted to Pepper and edited by Art Efron. The JMB reprinted the essay , in turn, from Stephen C. Pepper, “Metaphor in Philosophy,” Dictionary of History of Ideas, Volume 3. Philip P. Wiener, Editor-in-Chief Copyright, 1973 Charles Scribners Sons.
1. Special use of Metaphor in Philosophy. Metaphor in philosophy may be distinguished from metaphor in poetry by being primarily an explanatory rather than an aesthetic device. Its explanatory function is to aid in conceptual clarification, comprehension, or insight regarding a mode of philosophical thought, a problem or an area of philosophical subject matter, or even a total philosophical system. However, the boundary between the aesthetic and the explanatory use of metaphor is admittedly vague. A philosopher may even deliberately select a metaphor for its aesthetic vividness and impact (as with Bergson’s elan vital or William James’s stream of consciousness; and notoriously the Mystics), but the question of the Metaphor’s having philosophical relevance depends on its explanatory function. Does it contribute to an understanding of the philosophy?
There are relatively superficial uses of metaphor in philosophy, and there are permeating uses. The superficial uses occur when figures of speech are scattered along the written pages to vivify some other unusual conception, and drop out when the conception is grasped. But when the metaphor’s use is permeating, it may never completely disappear even after it gets ritualized and deadened under an accepted technical vocabulary within a philosophical school.
It has been frequently noticed that a new mode of thinking or a new school of philosophy as it is emerging and finding itself tends to be expressed in figurative language. This is inevitable before a technical vocabulary is developed with clear definitions and specific designations. Generally, this preliminary tendency is to be regarded as a superficial use of metaphor in philosophy. It is the more permeating use that deserves most attention.
In this connection the term “metaphor” should not be taken in too literal accordance with a definition often found in elementary books on prosody. It is not just a simile with the preposition “like” left out. It is rather the use of one part of experience to illuminate another-to help us understand, comprehend, even to intuit, or enter into the other. The metaphorical element may ultimately be absorbed completely into what it is a metaphor of. The one element, as frequently explained, is “reduced” to the other. The paradox of a metaphor is that it seems to affirm an identity while also half denying it. “All things are water,” Thales seems to say. In so saying he would be affirming an identity and yet acknowledging that it is not obvious, and that what is more obvious is the difference. He claims an insight beyond the conventional view of things. It becomes incumbent on him to show how the identity can be justified. The same is true of Lucretius’ identifying all things with atoms and a void, and of many other philosophers’ modes of identification of the whole of reality with some general aspect of it.