I've had some success of my own with lucid dreaming. Relatively speaking.
The problem I have is that I dream so rarely that it is almost impossible to develop habits. I still manage to go lucid about half the time I do dream, and manage to go lucid without inadvertently waking myself up about half again of those times.
I don't know if lucid dreaming has improved my rationality, but I do think that my rationality helps with the "oh, this is silly and must be a dream" reflex. There is correlation, but it is not obvious in which direction there is causation, if there is at all.
The hardest part in my experience is actually staying asleep once I go lucid. I have to very deliberately pay attention to the physicality of myself and my immediate surroundings in the dream, while ignoring any signals from my real body, or the dream will evaporate in seconds.
For me, the key to manipulating a dream was figuring out that dreams, even lucid dreams, don't seem to run on willpower. I can will something to happen with all my might, and nothing will happen. Rather than wielding willpower, I have to wield expectation. If I expect to see something, I will. There is an exception to this that I don't have an explanation for, though: I'm telekinetic in my dreams. All my dreams, no matter what they're about, whether they're lucid or not. You'd think this would make it easy to check if I'm dreaming, but I'm just so used to it that half the time it doesn't register as strange.
Does anyone know possible causes for rarely-dreaming-at-all?
Does anyone know possible causes for rarely-dreaming-at-all?
I very rarely remember my dreams.
In order for me to remember a dream I have to be unexpectedly woken up (at the right point in my sleep, obviously) and then I have to fix that dream -- by writing or talking or just repeating the key points in my conscious mind -- or it will fade away in a matter of seconds.
For all practical purposes I don't dream.
On the other hand I can do lucid dreaming, but the conditions have to be there: a morning when I can doze and no one will interrupt me. Happens rarely :-(
Note: this post is no longer endorsed by the author, for reasons partially described here.
In the spirit of radioing back to describe a path:
The truly absurd thing about dreams lies not with their content, but with the fact that we believe them. Perfectly outrageous and impossible things can occur in dreams without the slightest hesitance to accept them on the part of the dreamer. I have often dreamed myself into bizarre situations that come complete with constructed memories explaining how they secretly make sense!
However, sometimes we break free from these illusions and become aware of the fact that we are dreaming. This is known as lucid dreaming and can be an extremely pleasant experience. Unfortunately, relatively few people experience lucid dreams "naturally;" fortunately, lucid dreaming is also a skill, and like any other skill it can be trained.
While this is all very interesting, you may be wondering what it has to do with rationality. Simply put, I have found lucid dreaming perhaps the best training currently available when it comes to increasing general rationality skills. It is one thing to notice when you are confused by ordinary misunderstandings or tricks; it is another to notice while your own brain is actively constructing memories and environments to fool you!
I've been involved in lucid dreaming for about eight years now and teaching lucid dreaming for two, so I'm pretty familiar with it on a non-surface level. I've also been explicitly looking into the prospect of using lucid dreaming for rationality training purposes since 2010, and I'm fairly confident that it will prove useful for at least some people here.
If you can get yourself to the point where you can consistently induce lucid dreaming by noticing the inconsistencies and absurdities of your dream state,[1] I predict that you will become a much stronger rationalist in the process. If my prediction is correct, lucid dreaming allows you to hone rationality skills while also having fun, and best of all permits you to do this in your sleep!
If this sounds appealing to you, perhaps the most concise and efficient resource for learning lucid dreaming is the book Lucid Dreaming, by Dr. Stephen LaBerge. However, this is a book and costs money. If you're not into that, a somewhat less efficient but much more comprehensive view of lucid dreaming can be found on the website dreamviews.com. I further recommend that anyone interested in this check out the Facebook group Rational Dreamers. Recently founded by LW user BrienneStrohl, this group provides an opportunity to discuss lucid dreaming and related matters in an environment free from some of the mysticism and confusion that otherwise surrounds this issue.
All in all, it seems that lucid dreaming may offer a method of training your rationality in a way that is fun,[2] interesting, and takes essentially none of your waking hours. Thus, if you are interested in increasing your general rationality, I strongly recommend investigating lucid dreaming. To be frank, my main concern about lucid dreaming as a rationality practice is simply that it seems too good to be true.
[1] Note that this is only one of many ways of inducing lucid dreaming. However, most other techniques that I have tried are not necessarily useful forms of rationality practice, effective as they might be.
[2] And, to be honest, "fun" is an understatement.