Final answer:
The metaphorical subject being described is 'truth,' which is portrayed as fragile and capable of being easily overwhelmed by lies. Literature uses metaphors and similes to express complex ideas in a relatable way, as seen in Socrates' allegories and the poetry of Edna St. Vincent Millay.
Step-by-step explanation:
The metaphorical subject described as "truth, brittle and faint, burns easily, its fire as hot as the fire lies make" likely pertains to the fragile nature of truth and how it can be overwhelmed by lies. In literature, metaphors and similes are used extensively to convey deeper meanings and to compare one thing to another for a more vivid understanding of an idea. For instance, Socrates refers to the prison-house as the world of sight and the light of the fire as the sun. These metaphors are meant to challenge our perceptions and encourage us to consider different perspectives.
Famous works, such as the poem "First Fig" by Edna St. Vincent Millay uses metaphor to succinctly express the brightness and ephemerality of life. In these lines, life is compared to a candle burning at both ends, suggesting that life is beautiful but can be consumed rapidly. This perspective on life's fleeting nature and its burning passion can be linked to our understanding of the truth, where it gives off a brilliant light, but is also vulnerable to destruction.
Lastly, in literary discussions about truth, references are often made to the experience of Socrates' prisoner in the allegory of the cave, who, once enlightened, sees the true form of reality and returns to enlighten others, only to be rejected. This metaphor underscores the difficulty of communicating profound truths to those not ready to perceive them. Thus, the metaphor you've provided suggests that truth itself is potent and powerful but can be easily damaged or concealed by falsehoods.