When an author wishes to break their audience away from their usual modes of thought and understanding, whether to simply re-set their perspective in the course of a line of reasoning, or to encourage them to think inwardly, or to imagine themselves in a similar situation, the way to do this is through one of these devices:
An anecdote is a short story, like one you would tell a neighbour, or one you would tell a friend about a neighbour. When employed as a device, it encourages the reader to view a situation from a common perspective; from the perspective of a lived reality. It can very effectively provide a example, serve as evidence to support a claim, and bring a reader down to earth.
An allegory is a story, longer and more detailed than an anecdote, which can be interpreted to reveal a hidden meaning.
An aphorism is a truism, an adage - a clever statement of general wisdom. It reminds us of what we know to be true, and can give us pause to consider; re-setting us, and anchoring us in the here and now.
An allusion is an indirect reference, an expression designed to call to mind the object of the one who alludes.
Possibly the most famous allegory in the English-speaking world, Plato's allegory of the cave was written more than 2,000 years ago, in Ancient Greece (and definitely not in the English language). In it, a story about prisoners in a cave becomes a rich stage for an examination of education, perception, reality, and more.
In I Choose Exile American author Richard Wright makes use of an anecdote to drive home his point about the difference between American and European attitudes toward race.
Perhaps one of the most enduring characters from modern English fiction is the (Dutch) Professor Van Helsing. I can think of at least five iterations of his character, from appearances in comic books, anime, and film. The popularity of the character is assured by the strength of the original, and here, in this excerpt from Dracula he makes allusion to some great mystery, hidden in the depths of human suffering.
One of the strongest uses of an aphorism, employed as a rhetorical device, is exemplified by the funeral oration in William Shakespeare's Julius Caesar. Here, Marc Anthony delivers a speech about the controversial leader. The aphorism is found in the third and fourth lines of the verse, and it disarms the audience of any ill-will they still hold toward the deceased.