We know that our brain is sort of probabilistic, pattern-matching engine that interprets patterns all around itself, and building a large image of environment where the body resides. Considering that, conscious process is a delicate and complex process occurring inside one's brain, and the brain can render the world beyond one's body (their environment) while maintaining autonomous functions and coordinating body parts to manipulate its environment. I wonder about its capability on understanding it itself.

Consider that one is trying to diagnose flaws in their conscious process, using simple logic-check and cognitive tests they created themselves (or any test that I might not be aware of).

Is it possible for them to accomplish it? If they do, how would they accomplish it?

Basically I'm asking how would one know that their brain isn't working the way it is supposed to?

EDIT: To emphasize, this question is specifically asking how would someone detects flaw in his/her own mind, all by him/herself


closed as off-topic by a CVn May 12 '15 at 10:46

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    $\begingroup$ I believe this would be a better fit on the Cognitive Sciences SE. $\endgroup$ – Frostfyre May 9 '15 at 13:54
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    $\begingroup$ Whenever I hit my head, I always speak two words that I know rhyme, and analyze how my mouth moves. If it moves the same each time, I am reasonably confident I can still speak correctly. $\endgroup$ – DaaaahWhoosh May 9 '15 at 14:31
  • $\begingroup$ @Frostfrye Oh, I am unaware of Cognitive Sciences SE's existence, thanks for pointing it up. How should I move this question to that SE? $\endgroup$ – Hendrik Lie May 9 '15 at 15:05
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    $\begingroup$ If you do post a copy of this question on the Cognitive Sciences SE, put a link in this question to that post (and vice-versa). That way the answers which accumulate in both forums can serve both questions. $\endgroup$ – Henry Taylor May 9 '15 at 16:40
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    $\begingroup$ This is, by the way, question #2000. $\endgroup$ – HDE 226868 May 9 '15 at 16:42

(Assuming the anomaly-checker is internal)

The problem is the fact that the part of the brain that checks if the brain is working could not be working. Imagine one section of the brain, for example in the very front. If the brain suffers any form of damage, this part of the brain runs checks all over the other parts of the brain. But, if this part gets damaged, it is unable to check if it is working or not, and therefore left completely unknowing. A work-around would be to assume it is damaged if uncheckable (damaged until proven innocent!). But if the diagnostic part got damaged (the bit that checks what sections should be checked) got damaged, it would tell the testing section everything is fine, and the brain would never even know it was damaged. Even if you add multiple sections to diagnose, it is always possible they will all get damaged.

TL;DR version: There is no way to make sure the brain is 100% able to check if it has an anomaly, because the anomaly-checker could get damaged.

(If it is an external test(physical)) The diagnostic part of the brain gets damaged, so the person never asks to take the checking test. Unless the test is regularly taken, people would be crazy without knowing.

  • $\begingroup$ I learned that in studying for a Computer Science degree. A flawed system cannot be guaranteed to evolve toward a more correct state. $\endgroup$ – JDługosz May 9 '15 at 21:30
  • $\begingroup$ The anomaly checker is done internally.., 1+ for pointing it $\endgroup$ – Hendrik Lie May 10 '15 at 16:31

The answer is complicated because the first step is monumentally dizzyingly difficult:

The first step to creating a test to determine if one's brain is working the way it is supposed to be is to define how the brain is supposed to work.

As a challenge, consider those with synesthesia vs. those of paranoid schizophrenia. Both create effects which cause the brain to see things differently than the rest of the world. Synesthesia is considered a beautiful thing, full of possibilities. Paranoid schizophrenia is considered a medicateable disease.

And then consider John Nash, a paranoid schizophrenic who decided to not take any medication for his disease. Was his brain not working the way it is supposed to be? Never forget that he became a Nobel Laureate who revolutionized economics with the theory now known as the Nash Equilibrium.

He is also an excellent subject for your research because he not only did what you are talking about, but he did it beautifully enough that it was later romanticized into a movie, A Beautiful Mind.


Now, in this moment of sanity and presumably proper cognitive function, take an exhaustive set of IQ, personality and physical-dexterity tests. Keep all of the results for comparison against your scores on future iterations of the same tests. Then periodically retest yourself and watch for escalating differences between your current and earlier results.

This is not so much a method for detecting the presence of mental anomolies, rather it detects the escalation of any existing anomoly. Escalation is currently considered to be a symptom of many mental disorders, and mentally healthy people are commonly referred to as stable, as-in non-changing. So the presence of escalation among the measurable traits of your mind, might very well mean that you are crazy.

...either that, or you are finally growing up.


A person, noticing or suspecting that something about their brain might be amiss, could run all sorts of tests.

These tests need to be as objective as possible, so there must be some sort of outsisde reference.

Someting i personally tested once was my phone's chess app: testing my skills in the game versus my regular difficulty setting proved feasible (and unfortunately successful in the context of the test, although, happily, after leaving the hospital and not needing that funny painkilelr cocktail any more i got back to the old settings).

Other possible tests would include IQ tests, Sudokus as long as they are more or less controllably rated according to their difficulty, crossword puzzles and the likes, so long as the person has a reasonably good memory about how well they typically perform.

All those tests are only able to test one's logical capabilities, though.

Playing trivial Pursuit, if one does so often, could (with variable precision) hint towards the integrity of one's memory, although given the fact that human memory is anything but precise even at the best of times, it might be difficult to evaluate the result of such a test.


Applying some technology this is actually simple. Create a virtual reality test comprising a cross section of human behaviour. Add some drugs into the mix to prevent people from knowing they are in a test. Content can be changed over time as insight progresses. A baseline score can be established by many people doing the test, statistics providing the borders inside which behaviour is considered normal.

Can of worms? Yes. Would I take it? Do I feel lucky today? Mmmm. Makes you think of this?


René Descartes supposed, that ability to have doubts is the normal way of operating of consistence

In this manner, Descartes proceeds to construct a system of knowledge, discarding perception as unreliable and instead admitting only deduction as a method. In the third and fifth Meditation, he offers an ontological proof of a benevolent God (through both the ontological argument and trademark argument). Because God is benevolent, he can have some faith in the account of reality his senses provide him, for God has provided him with a working mind and sensory system and does not desire to deceive him. From this supposition, however, he finally establishes the possibility of acquiring knowledge about the world based on deduction and perception. In terms of epistemology therefore, he can be said to have contributed such ideas as a rigorous conception of foundationalism and the possibility that reason is the only reliable method of attaining knowledge. He, nevertheless, was very much aware that experimentation was necessary in order to verify and validate theories.[42]



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