Implications for cognitive science?

So bit by bit I've improved my psychonautics, as it were, culminating in a recent lucid dream so vivid that I almost wasn't sure it was possible at the time. I had had lucid experiences before where I would be walking in some sort of field with grass beneath my feet, and remember touching the ground and feeling all the moisture of the plants and the dirt just as real as anything, but my recent lucid was more vivid in all respects. My vision was clear, my sense of touch, and most notably my hearing...I listened to my dad talk to me at length, the topic of which I can't remember but the feeling was unmistakable. Everything about him was spot on...or was it?

Currently I'm studying linguistics in college, and as part of my degree program we have the opportunity to learn about the field of cognitive science as a whole, given that language comprises just one small sector of the human cognitive faculties. I took the introductory cogsci course last semester. It was all very fascinating, and in my various other readings about the topic of cognition I've started to get the same impression from the science that most would-be lucid dreamers must naturally accept if they are to have any hope of achieving lucidity--that is, what we think we know about the world very much comprises mere suggestions from the brain about how reality could be.

A good example I've heard pointed out is in painting. Imagine a canvas painted with the image of a bridge, and standing relatively far away observing this photo you might notice some people making their way across--little heads and arms waving as they walk. Get a closer look, however, and you might find that these "people" are nothing more than cleverly placed blobs of paint--they don't have arms or eyes or mouths or noses or really much of anything at all. Yet from afar the brain gives the distinct suggestion that there are people walking on the bridge.

An example from my most recent dream also gives the same impression. Amazed by how utterly real my dream environment was, seemingly down to the last detail (I had a false awakening in my room then after performing a reality check walked out into the hallway--all familiar locations to me), I saw my computer open on my desk and saw a huge block of text on the screen. Surely there must have been something written there. Well, lo and behold, once I got up closer, there were certainly lines of words written, but they made little if any sense--even if the individual words were intelligible, most of the strings weren't even syntactically felicitous, and in some cases the letters became jumbled around before my very eyes.

Consider now a real-life example where total jibberish sentences, nonetheless written in the Latin script, are in a block of text and presented to viewers from a bit of a distance. Compared to a coherent block of text from the same distance, viewers will not be able to discriminate the jibberish from the non-gibberish, but the brain generates the same suggestion: Words. Text. The reason for why you can't read them even from up close in a dream then should be obvious: In reality your brain gives the best estimation it can and in continuing to observe things you're only providing it with more information to guess on, and in reality these things are concrete and unchanging, separate from the brain that's interpreting them. On the other hand, in a dream, everything is generated from within, so the brain must do the reverse: Rather than guessing at what's on the outside, it has to make shit up about what's on the inside, so to speak. When the suggestion need only be vague, like text from afar, this is easily done. However, when forced to come up with specifics, the mechanism is surprisingly easy to break. Other examples of this you've probably already used are things like the clock face changing unpredictably, distorted reflections, etc.

Anyway, I guess to an extent I feel as though I'm telling a lot of you things you already know, but in a way this is all getting at what may or may not be a rhetorical question (you decide :P). What does it mean to be "vivid"? Is it really the case that our dreams are as vivid as they seem, or are lucid dreams just a more extraordinary way of fooling ourselves with respect to reality? It's probably already clear to many of you just how imprecise human perceptual systems are, but I think lucid dreaming gives us a sense of just how creative the brain can be in making our delusions seem as obvious and real as night and day.

Don't know if this is useful to any of you but at the very least that last lucid dream I had has really encouraged me to continue trying even harder. It was amazing the kind of environment my brain could construct and equally amazing to me where it fell short, even as I was observing it in the dream. I had a clarity of thought I don't think I've ever had in a dream...I'm just rambling by now, but I hope it all makes sense.

In a way the reason for this should be obvious.