Final answer:
An allusion is an indirect reference to something without explicitly mentioning it, whereas an illusion is a false impression of reality. Allusions are used in literature to add depth and invite connections to other works or historical events. An example of an allusion is comparing a challenging task to a Herculean labor.
Step-by-step explanation:
An allusion is an indirect reference to something without explicitly mentioning it. For instance, in literature, an allusion to the Bible might appear in a poem to enrich its meaning. Similarly, one might find a sentence like "Despite facing a Herculean task, she completed the assignment with finesse," which contains an allusion to the Greek myth of Hercules and his twelve labors. This enriches the sentence by comparing the daunting nature of the task to the legendary challenges faced by Hercules.
Allusions are not to be mistaken for illusions, which are false impressions of reality. A magician might create an illusion to trick your senses, but unlike an allusion, it does not refer to anything beyond the immediate deception.
When authors include allusions within their works, they invite the reader to make connections to other texts, events, or historical figures, adding layers of meaning to the original text. For example, a reference to a "verdict not unlike the one in the trial of Jean Gianini" serves as an allusion to a historical court case which would prompt the reader to consider the similarities and implications associated with that allusion.