Illusions vs. Hallucinations – Does Truth Always Matter?


Have you ever been so tired, feverish, or just perplexed, you couldn’t with certainty tell whether the postman at the door was real? Or, have you been extremely concerned when your wife declared that even though David Bowie is dead, she was singing the Marseillaise with him in the kitchen last night? Is there a scientific explanation for these moments? Am I just going bonkers? Is my wife ill in some way? Was it an illusion or hallucination, or in fact, reality?


An illusion is a type of perceptual or cognitive error. Everyone suffers some of them sometimes. They can affect any sense, but the visual illusions are the most common. Depending on the stimulus, which is always present in case of illusions, the result will be ambiguous or paradoxical, but generally the same in most people. Painters, filmmakers and magicians take advantage of this phenomenon, big time.

illusion cutting womanWe know that the Moon is not the size of an orange, and that a magician doesn’t really cut a woman inside the box with a chainsaw. Nevertheless, since everyone gets “tricked” the same way, some images can look very “realistic” and good magicians can certainly delight or scare an audience with their trickery.

Other types of illusions may confuse those who experience them into thinking the thing is something other than it really is. Perhaps a group of people standing outside at night believe they see something like a UFO, but in reality it is an optical illusion caused by lights in the sky.

Fata Morgana - illusion
Fata Morgana illusion (not a UFO)

Illusions can also occur when people have particularly strong beliefs or hopes that they will experience a given thing. Sometimes religion may be the source for such illusions. A person may wish so strongly that they see an angel in the church, that when light shines through a particular window onto a religious object that they convince themselves that the light is what they want it to be. But in the case of the illusion, the light must be present for this incorrect perception.


Unlike illusions that are distorted truth, hallucinations are not based on one.  What is experienced is not based on any form of reality that others may perceive. No external stimulus is present for any of the types of perception, be it visual, auditory, olfactory (smell), gustatory (taste), or tactile (touch).

Hallucinations are mostly confined to people with mental illnesses, but also to those who suffered brain damage as a result of trauma, infection, intoxication by drugs or alcohol, and some other conditions. A person suffering from delirium tremens as a result of alcoholism may feel lice crawling over his skin or be frightened by red spiders and pink elephants. Schizophrenic patients often hear voices of their persecutors, their own conversation with others, or their own thoughts spoken aloud (echo de pensée).

Play the video below to hear something like what a person with schizophrenia might hear during an auditory hallucination:

Additionally, imaginings as immediate and vivid as perception but not mistaken as such, are called “pseudo-hallucinations.” Those are most often a result of extreme emotions, exhaustion, or stress. For instance, Shakespeare’s Macbeth, planning to murder Duncan, “seeing” a dagger…”Art thou not, fatal vision, sensible to feeling as to sight? Or art thou but a dagger of the mind, a false creation, proceeding from the heat-oppressed brain?”

There are individual differences with regard to hallucinations. The same individual may experience different hallucinations on different occasions, which can involve more than one sense at the same time, but more often focus on one. The nature of the hallucination is determined by the individual’s present and previous experiences.

What is the root cause in the brain of hallucinations? “One major theory is that hallucinations are caused when something goes wrong in the relationship between the brain’s frontal lobe and the sensory cortex, said neuropsychologist Professor Flavie Waters from the University of Western Australia. For example, research suggests auditory hallucinations experienced by people with schizophrenia involve an overactive auditory cortex, the part of the brain that processes sound, said Professor Waters.”

Not all hallucinations are intrusive, scary or negative, even in mental illnesses like schizophrenia. And as mentioned earlier, hallucinations can be benign and experienced by people without diagnosable illnesses or drug activity at all. People have been known to experience hallucinations during the process of falling asleep. Factors such as lack of sleep, stress, trauma and grief may also upset the relationship between the brain’s sensory cortex and the frontal lobe.

An interesting question I’d like to ponder more is the one in this post’s title. Does truth always matter? After all, many people in history who have been subject to illusions choose to believe the illusions as true, despite science (or even logic) telling them that they’re not. Those who hallucinate who believed the hallucinations to be true may eventually realize they were not, while others believe them true indefinitely. Even if a person hallucinates and realizes immediately that it is not reality (this can be the case) may be somehow affected by experience. There’s good and bad in all cases, as well as advantages and disadvantages.

What are your experiences with illusions and hallucinations, if you’ve had any? Are there experiences you’ve had that you truly believe were true, that others insist were not?



27 thoughts on “Illusions vs. Hallucinations – Does Truth Always Matter?

  1. A Fine Hole November 6, 2017 / 4:20 pm

    I’ve experienced 3 minor auditory hallucinations in the past year, two on a regular basis. At night while trying to sleep I often hear the very loud crying of my 1 year old son, but when I go to his room he is sleeping soundly. Also from time to time at night there is classical music coming from downstairs, but disappears when I hit the hallway. The other is rearrangements of the notes of guitar solos in songs I know like the back of my hand on new listens. That only a few times. I don’t know if it’s sleep deprivation or bipolar illness.

    Liked by 1 person

    • updownflight November 6, 2017 / 4:57 pm

      Thank you for sharing, A Fine Hole. I think sometimes it’s difficult to know. Please do talk about these hallucinations with your doctor and/or therapist. I’m glad, at least, that they haven’t been too disturbing for you.

      Throughout the years I’ve had different types of hallucinations. I wondered, too, if my bipolar disorder made me vulnerable to all of them, or if I’ve just been like other people at times, and had different forms unrelated to mental illness. The brain is a pretty strange organ, for sure.

      Liked by 1 person

      • A Fine Hole November 6, 2017 / 5:11 pm

        Thanks a lot for sharing and the advice. To be honest I’m a bit scared to share it with my psychologist,psychiatrist, or wife because they might think I’m experiencing psychosis, which I don’t believe I am. Although I’ll probably take the leap and tell my wife soon. Did you go through telling a spouse and was it easier than you thought?

        Liked by 1 person

      • updownflight November 6, 2017 / 5:18 pm

        When I was truly in psychosis I usually did not even think to tell anyone because I didn’t even know I was experiencing psychosis. That became clear to my husband and doctors without me saying a word. When I did recall a hallucination or delusion a while after-the-fact I did tell them. My doctor knew I had had psychosis, so he knew I had bipolar 1. Really, bipolar 1 should not be any scarier than bipolar 2. Yes, psychosis is scary, but only treatments change a bit. Usually for the better. When I did experience musical hallucinations, like you, and visual distortions I believe my moods were relatively stable. Given that, I had no fear of telling my husband or doctors. Of course I was worried what in the heck was causing them, but I felt a certain amount of control having the insight. That gave me strength. Ultimately, all I wanted was to receive the right treatment so I could be as well as possible.

        Liked by 1 person

      • A Fine Hole November 6, 2017 / 5:41 pm

        That’s really good to hear, it sounds like you improved or were given better treatment once you became aware. Thanks a lot for your input, it’s very helpful.

        Liked by 1 person

  2. Coping November 6, 2017 / 5:15 pm

    Love this post. Evoked many thoughts, memories, and experiences. On occasion I will randomly have a memory almost like a de ja vus and scroll through the recesses of my mind to ascertain where that memory came from. Was it a dream I had, a past life experience, an actual event that I suppressed, a book I read, a story someone told me or have I just lost it.

    Liked by 2 people

    • updownflight November 6, 2017 / 5:25 pm

      Hi Coping. Thanks so much!

      I can relate to a lot of what you said. Trying to put my finger on similar thoughts and memories.

      When I was in the hospital a number of times I was apparently in psychosis, but I don’t remember those hospitalizations. I had blackouts. Sometimes I have flashbacks and I wonder if they are of times I previously didn’t remember, or if they are just creative but scary thoughts that are born from something else.

      I have written in the past about various types of hallucinations I’ve had, not just when psychotic, but when seemingly stable. I’ve also written about how some of my maladaptive daydreaming could become so realistic at times that I’d wonder if those dreams really happened. I’ve even had nighttime dreams that seemed significant enough to switch my moods. In the past, I sometimes thought they were signs from my higher power. Who knows? Maybe they were or maybe they weren’t, but they were still significant in my life. That goes back to my question in this post. “Does truth always matter?”

      Liked by 1 person

      • Coping November 6, 2017 / 6:42 pm

        Whooaaa is all I have to say about this. OMG I cannot tell you how much better I feel knowing I am not alone. Switching moods (which can occur after a look someone gives me) as well as signs from the divine. Thank you for this post. You describe this phenomenon if you will to a “T”.

        To answer your question “Does truth always matter?”….. I could say so much much. At this point in time “truth” does not matter as after events that you’ve read in my posts have wiped clean all the “truths” I spent my life believing, and in the process dedicated a lifetime to those “truths”. I am at a place right now where I do not believe there is any “truths” that we as humans can collectively fully believe, trust, no concrete proof, or gee my mind is racing and I hope I’m explaining myself properly….but basically I think the Truth is a completely different, unique, incomparable mindset, based on so many factors ie childhoods, genetics, people who come and go, marriages, lovers, children, a comment from a teacher in grade 2 can change ones reality forever. So the older and wiser I become the more I realize reality, truth and veracity is individual as opposed to homogeneous. Thanks for my new OCD for the day!!!!

        Liked by 1 person

      • updownflight November 6, 2017 / 7:19 pm

        Oh please, only if your new OCD for the day yields good for you!

        I really enjoyed reading your answer to the question “Does truth always matter?” You are so right that there are so many factors involved and that reality is definitely an individual thing. My personal goal is to recognize a truth when it is the logical truth and/or one that allows me to accept my situation or process it effectively.

        Liked by 1 person

      • Coping November 6, 2017 / 7:45 pm

        Of course this ocd du jour is good! As for your goal for recognition of a logical truth…for me I don’t even try anymore. What seems logical today seems preposterous a week later. But I love how you say at least a truth “that allows me to accept my situation” or at the very least process it effectively. That’s deep yo.

        My logical truth is this: at the end of the day this illusion/hallucination/de je vus/time travel/hell/purgatory/reincarnation or whatever this existence is, it’s mine. My perceptions, cognizance or awareness will never be the same truth as any other human being and even more thought provoking is my truths swing like a pendulum so yeah….is there even really a “truth”?

        Liked by 1 person

      • updownflight November 6, 2017 / 8:14 pm

        Well, I think we all have the right to choose our own truths as long as they don’t hurt anyone else. Ultimately we should try to chose the truth that makes us happiest. Maybe to a person on the outside my situation looks pretty sad, but I try my best to see it as sufficiently good most of the time. Occasionally my mind sways a bit, but I fight to continue to see the glass half full.

        Liked by 1 person

      • Coping November 6, 2017 / 10:36 pm

        Again depends on many events I encounter literally daily. I have been diagnosed with bipolar as well in addition to agoraphobia and social anxiety. I struggle with that label as I feel like everyone has ups and downs and contentment diss disappointments , regrets, poor decisions and no one will talk about it let alone admit it. I am also an empath which exhibits the same symptoms. Oh I don’t know but I do know my self acceptance of the good and bad and the reality of my self sabotage is just who I am. Thank you for the great chat today. You are on another level of consciousness that most people will never reach

        Liked by 1 person

      • updownflight November 7, 2017 / 1:35 pm

        Coping, I very much enjoyed our discussion and your great contributions on this topic. You gave me a lot of things to think about, too.

        Liked by 1 person

  3. ventingthoughtsblog November 6, 2017 / 6:33 pm

    Once I an extremely tall man standing behing my room’s door. But I was half asleep so that was ruled out as a hallucination.

    Liked by 1 person

    • updownflight November 6, 2017 / 7:11 pm

      I think almost all people (with and without mental illness) have had some kind of moment when they thought they saw or heard something unexpected. It is so true that when half asleep we can have pseudo-hallucinations.

      Liked by 2 people

  4. Do it your way November 6, 2017 / 7:06 pm

    I’ve broke my nail last night when I was sleeping (it happend because I kicked in the wall).
    When I checked my nail in the morning I saw It wasn’t illusion nor halucinacion.
    But now seriously I had an hallucination once when I was very tired, I didn;t slept more than 48h.
    It is important to rest enough and to keep your sleeping routin under control, because when your mind is too tired you can experience not so nice things.

    Liked by 1 person

    • updownflight November 6, 2017 / 7:21 pm

      That’s so true! Sleep is so extremely important for our mental well-being. Not just that of the mentally ill.

      Liked by 1 person

  5. Mohamad Al Karbi November 9, 2017 / 12:22 pm

    Thank you Cindy for the rich information provided here. I know the titles but I never understand them in this clear and detailed way. I use “illusion” if the term is correct in my case to imagine good things whenever I’m in bad mood. I find it motivating in someway.

    Liked by 1 person

    • updownflight November 9, 2017 / 2:28 pm

      I find it very interesting how many meanings and/or usages there can be for a single word. Whenever I see Daily Post words du jour, I look them up in the dictionary. Not because I don’t know their meanings, but because I sometimes don’t recall them all. Urban Dictionary also provides meanings that may just be locally used. It’s fun to super analyze words.

      In Arabic, do many words have various meanings?

      Liked by 1 person

      • Mohamad Al Karbi November 9, 2017 / 5:20 pm

        Yes, it’s the beauty of a language. Many meanings for the same word. Arabic is very rich language. You can taste its beauty most in poetry (especially the old one) and Quran. Again, thank you Cindy. I’ve learned something new from reading this post. I read your post earlier but I wasn’t able to comment until today

        Liked by 1 person

  6. Orvillewrong November 28, 2017 / 6:49 pm

    An extremely interesting post, thank you also for approving my comments on other sites.

    Liked by 1 person

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