Using MRI scans, scientists can analyze what is happening in our brains when we look at illusions. They’ve learned that neurons can actually compete with one another to see light and dark spots. The winning neurons influence the message your brain gets and, therefore, what you end up perceiving [source: Hogenboom].

• 1 Troxler’s Effect. Source: Mighty Optical Illusions.
• 2 Chubb Illusion (luminance) Source: Wikimedia.
• 3 Checker Shadow Illusion (contrast) Source: MIT.
• 4 Lilac Chaser (color)
• 5 The Poggendorff Illusion (geometric)
• 6 Shepard’s Tables (size)
• 7 Kanizsa’s Triangle (Gestalt effect)
• 8 Impossible Trident (impossible objects)

Illusion, a misrepresentation of a “real” sensory stimulus—that is, an interpretation that contradicts objective “reality” as defined by general agreement. An illusion is distinguished from a hallucination, an experience that seems to originate without an external source of stimulation.

They can occur for many reasons, such as the effect of light on an object, insufficient sensory information about an object, or errors in an individual’s processing of sensory details. The refraction of light can cause rainbows and mirages, two illusions that are dependent on the atmosphere.

Magicians create illusions by taking advantage of how we perceive stimuli and process information. Illusions are revealing, because they separate perception from reality. Magicians take advantage of how our nervous systems — our eyes, sense of touch, minds and so on — are wired to create seemingly impossible illusions.

The Black Door in Dawnstar asks, “What is life’s greatest illusion?”, to which the correct answer is: “Innocence, my brother.” learned during the quest “The Cure for Madness.”

The further quantum physicists peer into the nature of reality, the more evidence they are finding that everything is energy at the most fundamental levels. Reality is merely an illusion, although a very persistent one.

“Our minds aren’t passive observers, simply perceiving reality as it is. Our minds actually change reality,” said Alia Crum, an assistant professor of psychology and director of the Stanford Mind and Body Lab.

Albert Einstein once wrote: People like us who believe in physics know that the distinction between past, present and future is only a stubbornly persistent illusion. Time, in other words, he said, is an illusion. Many physicists since have shared this view, that true reality is timeless.

Albert Einstein

But it should be noted that illusion is composed of various images that are necessarily drawn from reality. Illusion cannot exist independently of reality. Rather, illusion is also a phenomenon involving our perception of reality, whether it is a “true” representation of that reality or not.

The correspondence theory says that truth is that which corresponds with reality. To be more precise, truth is a quality that applies to beliefs, statements and propositions which describe reality the way it actually is. Beliefs, statements and propositions represent or depict reality as being a certain way.

Truth is the property of being in accord with fact or reality. In everyday language, truth is typically ascribed to things that aim to represent reality or otherwise correspond to it, such as beliefs, propositions, and declarative sentences. Truth is usually held to be the opposite of falsehood.

deceive, mislead, delude, beguile mean to lead astray or frustrate usually by underhandedness. deceive implies imposing a false idea or belief that causes ignorance, bewilderment, or helplessness.

A lie is an untruthful assertion. The speaker intends to cause belief in the truth of a statement that the speaker believes to be false. Hence, a lie involves an intention to deceive. The speaker also implicitly assures or promises the hearer that the statement that is made is true.

Lying is a form of deception, but not all forms of deception are lies. Lying is giving some information while believing it to be untrue, intending to deceive by doing so. The liar intends to deceive or mislead.

1a : favorable opinion especially : excessive appreciation of one’s own worth or virtue … the landlord’s conceit of his own superior knowledge … — Adam Smith. b(1) : a result of mental activity : thought. (2) : individual opinion.