This is not really a philosophy that I live by or use to form my conception of what my or anybody's life is. But I find the thought that everything that happened in the past is only part of reality in the form of a resedue in our memories interesting. That isn't really true. If I break a cup that I use every day, I cannot use that cup to drink tea from. And if I build a house, I can live in it in the future even though the action of building it and all the experiences I made during that time is nothing but a memories. But applied to activities that don't transform part of the physical reality in a specific and definite way, it has some truth, and realising that gives me a curious feeling.
Somebody asked me once, after I gave an introductory talk about Lucid Dreaming, if what somebody experiences during a dream is somehow more real than a dream or still just a dream. I've answered in a way that I thought as honest but was maybe not a clear answer. I said it's still a dream and what stays after the dream is nothing but the memory of it. That's not wrong. But had I taken the time to give a longer answer, I should have also explained the context in which I consider this to be the case. Regular dreams are usually incredibly volatile, especially for somebody who doesn't pay much attention to them and doesn't even try to remember them better. For most adults that's how they remember the majority of the few dreams that they remember at all. Most lucid dreams, it is often said, are a very positive experience. People who train to become lucid dreams mostly consider a lucid dream a success that comes way less often than they wish. These circumstances alone make a lucid dream easier to remember. Some see the memory of a lucid dream in a different class from non-lucid dream memories all together. But of course there can be lucid dreams that you don't remember for long, or you forget the details after a while, or you don't recall at all after waking up (How would you know?). If you don't consider a dream special, it will fade more quickly. If your head is full of other pressing thoughts, if you're depressed or are currently very worried, and if you don't write them down, the memories of a dream will fade quicker. In my experience, given enough time, the memories of lucid dreams will fade into the same jumble of vague memories from long ago, which might be correct or complete or not at all (which doesn't correlate with the sense of how correct or complete they are, btw). That isn't to say that they weren't worth the effort I've put into.
All of that is also true for waking memories, though, isn't it? Yes, we keep much more of what we experience while awake because the short term memories are functioning a lot better then. But years later, what's left is a fading memory unless it is a special memory to you in some way or you do something to keep the it alive. And the jumble those waking memories fade into is the same where all the dream memories go. So, the more small, unimportantant memories accumulate, the more likely it will become that a dream memory is confused with a waking memory. I believe that, to a certain extent, this may be normal. To an extant to which it is not concerning, I mean. Did I see a deer in the northern fields where you usually keep away from two years ago? Or did I only dream that? Deer have no relevance to my life, nor have those fields or anything that seeing a deer north from the village would imply. So I don't care. This is something else than believing that what you dreamed last night to be true minutes or hours after waking up. That could become an awkward day at work or worse. It is also something else to come to the wrong conclusion from a reality check when you're awake. What I believe to be normal to some extent is the confusion of basically irrelevant memories.
In many ways, dream memories and waking memories are more similar than I thought for a long time. They are the same in some ways. A lot of the apparent differences can be explained by the lack of short term memories while dreaming or during the process of waking up (which can be both at the same time). So, are lucid dreams just dreams of which fading memories are the only thing that remains? Yes, just like your last night out, your holiday in Japan, all the films you've watched and podcasts you've heard. And no, just like everything else you experience, a lucid dream re-shapes and re-inforces neural connections and thus influences how you think, how you experience things from now on and what you will do in the future.