Sometimes people confuse figure of thought with figure of speech. These two devices are closely related in purpose but are not identical. The primary difference is that a figure of speech often uses specific words and word orders that become commonplace or even cliché due to overuse.
“In its broad sense, metaphor is not only a figure of speech but also a figure of thought. It is a mode of apprehension and a means of perceiving and expressing something in a radically different way. In such a sense, figurative images are not simply decorative but serve to reveal aspects of experience in a new light.”
– Ning Yu, “Imagery.” Encyclopedia of Rhetoric and Composition, ed. by Theresa Enos. Taylor & Francis (1996)
The purpose of a figure of thought is twofold. First, it improves the larger aesthetic impression of the communication, making it seem more elite, mastered or beautiful. Secondly, a figure of thought allows an individual to get across more abstract concepts that truly might not be definable with concrete terms. In some cases, using a figure of thought ends up being more concise than if a person tried to describe everything behind the idea.