An illusion is a distortion of a "actual" sensory stimulus—that is, an interpretation that contradicts objective "reality" as defined by consensus. A youngster, for example, who sees tree branches as goblins at night may be considered to be having an illusion. In science fiction, illusions are used to describe phenomena that violate our sense perceptions.
All sensory information we receive is processed by the brain in order to make any sort of meaningful perception of the world around us. This processing includes making predictions about what will happen next in order to plan actions or avoid dangers. Unfortunately, our brains are not perfect at this task, so sometimes we get lucky and something seems to make sense even though it's not true at all. For example, if I show you a picture of a cat and then ask you whether there is any chance that thing was once a dog, you would say no, even though both animals have similar features. This happens because our brains make assumptions about the world based on past experience that can lead to mistakes called "illusions".
Definition of Illusion Illusions are typically linked with tricks of the senses, such as optical and aural illusions that fool the sight or ear. An illusion in literature can be a narrative technique, such as a dream, vision, or other device that misleads, confuses, or deceive a character. The literary definition of illusion differs from that in theatre or film where illusions are used to create scenes that seem real but are not physically possible. For example, when King Lear sees his daughter Cordelia beneath an oak tree alive, he believes it is true even though she has been taken hostage by the enemy.
Illusions can also be used to describe characters who are completely mistaken in their beliefs about reality. For example, Othello thinks the handkerchief that Desdemona gives him before they marry is evidence that she has been unfaithful, so he murders her husband, Iago, out of jealousy. In fact, the handkerchief is proof of their love since it contains both their names. Othello doesn't realize this until after he has killed Iago.
Another example is Pygmalion, who dreams that his ivory statue comes to life. So obsessed is he with creating a perfect woman that when Galatea actually emerges from the marble, he falls madly in love with her.
An illusion is a sensory distortion that reveals how the human brain regularly organizes and interprets sensory stimuli. Although illusions alter our perspective of reality, most people share them. The emphasis on visual illusions is due to the fact that vision frequently dominates the other senses. However, many other types of illusions exist, such as those associated with hearing or touch.
Illusions can be divided into two main groups: perceptual and cognitive. A perceptual illusion occurs when an aspect of the physical world influences the way in which we perceive something else about that world. For example, when standing next to a wall, it may appear as if there's nothing behind it. This is because where there is no room behind the wall, our brains fill it in with information from other parts of the image. This is called "visualization." A cognitive illusion happens when our minds create pictures or interpretations of events that don't correspond with what actually happened. For example, if someone tells you that a map shows California to be larger than Texas, they're wrong but their statement is true. Cognitive illusions don't reveal anything new about the world or our ability to see it; they just show that our minds play tricks on us.
The term "illusion" was first used by Galileo who noticed that the Moon appears to shrink as it gets farther away from the Earth. This phenomenon is now known as "parallax".
A misleading depiction of something, a deceptive perception, or a mistaken belief are all examples of illusions. By presenting specific aspects, writers trick readers' senses of sight, touch, taste, and sound, causing them to picture what is happening. Writers use this visual language to create scenes that feel real even though they are not taking place "in reality".
In fiction, the term "illusion" can be used to describe any sequence of events that appears unusual or surprising when viewed from the outside but which makes sense given what has come before. For example, an illusion might be when someone assumes another's identity for revenge purposes. Or an illusion could be when the protagonist believes they have seen a ghost but later finds out it was just a figment of their imagination.
Thus, an illusion is anything that causes you to believe one thing while actually believing something else. The English language doesn't have a direct translation for this concept, so writers often make do with simple descriptions instead.