Why does even the most rational brain forget logic in a dream?

Question

Scenario 1) Now we all know gravity is real. Yet when we dream that we are flying we forget/or are oblivious to the entire concept of gravity as if you have never experienced gravity.

Scenario 2) When dreaming of a deceased relative long or recent sometimes the dream is in their lifetimes and during the dream the brain has no recollection of the event of their death.

In both these scenarios you can control the dream for example if you are flying you can change directions or set the scenery and are aware you are dreaming but the things you are unaware of are GRAVITY AND DEATH. And as soon as you wake up or figure out the reality you become awake. So my question is why does a brain forget reality/logic in a dream?

Answer 1

Neither rational nor logical

"...there is overwhelming evidence that Humans cannot be [rational]" - Daniel Kahneman (Thinking Fast and Slow).

To begin with, the brain is neither rational nor logical as you may think (to a large extent it is little rational and its logic is completely fuzzy). A perfectly rational and logical organ would not be able to keep us alive (such an organ could take 4 hours to choose between two bottles of wine).

So I assume that your question is more like:

How comes dreams often involve augmented reality?

On augmented realities

Try this: shut your eyes and try to imagine your lower body replaced with that of a horse. Can you do this?

You have not done this whilst dreaming, but whilst awake and conscious.

Can you bring memories of a deceased relative whilst awake? Sure you can.

So the ability to experience augmented reality is not reserved for dreams - we can incite such reality by conscious means, certain drugs or brain damage.

Whilst you were dreaming

There are various theories on why we dream and what happens whilst we dream.

A key to many theories is random brain activity. You actually experience this whilst awake when you leave the central executive mode (stay-on-task) and enter daydreaming one - where short thoughts are following in what often seems as random.

Such random activity is fully capable of triggering augmented reality, like a half-man half-horse.

There is a higher likelihood for such augmented reality to appear in dreams, since random activity is not tamed by the stay on task mechanism.

Answer 2

I don't think there's a real answer to the question, but I find it fascinating.

Have a look at this really nice paper, too. They asked lucid dreamers to approach other dream characters and ask them to do simple maths. (Not because they were interested in lucid dreaming per se, they just needed somebody to be able to decide what they would dream). The study was done with a low number of participants who were also lucid dreamers, so who knows how valid this is for the general population. But they found that people reported that their dream characters got all mysterious and were seemingly unable to answer the question. In one case, one character covered their face, started crying and ran away. In the other case, they answered cryptically 'gray zone'.

So while maths is not logic, this exploratory study does show that in dreams we can't do the simply things we have no problem in doing in real life.

I know this doesn't answer your original question of why this is the case, but I thought you might find it interesting.

Warning: the paragraph below is pure handwaving and speculation, NOT to be taken as evidence-based

As pure speculation/brainstorming (so please don't take this seriously, it's just a thought), I like to think that logic might depend on our brain chemistry. While we tend to think that logic is the one thing that we can trust on (Descartes and Bertrand Russell certainly did), it might be the case that logic as we know it depends on our brains. So when we are in a dofferent cognitive state, our logic is different.

Answer 3

Not everyone forgets gravity in dreams. I'm speaking out of my experience with lucid dreaming, which allows thousands of people to act consciously in their dreams. This allows them to examine dream concepts in more details, as well as perform experiments.

There's a lucid dreaming flying technique, which is all about manipulating the gravity within a dream. Multiple people have independently discovered over the years, which I refer to as "Attraction flying". I saw a mention of the attraction flying in the 1993 book "The art of dreaming" by Carlos Castaneda.

The technique manipulates gravity in the following ways - first, a person levitates over the surface, then uses willpower and intent to "fall" towards a distant object. Once the person is close to that object, another object is selected to fall towards. This creates a zig-zagging flight pattern, somewhat similar to how "Spider man" uses webs to move between skyscrapers.

The existence of this technique, and the fact that multiple people have independently discovered it makes me think that the brain is capable of imagining gravity in a dream.