Mirrors present an interesting puzzle in lucid dreams because their main property in real life - reflection - is driven by the laws of physics. Yet these laws are entirely moot in dreams.
In fact, the only reason things do follow the laws of cause and effect in any dream is because we expect them to.
Physical law drives our entire conscious experience and we carry it with us - both consciously and unconsciously - into the dream world.
Every "normal" construct in the dream world (cars, houses, human beings, bicycles, swimming pools, trees, dogs, clothing) has been drawn from your waking experience. If you were blue and lived on Titan, you would no doubt dream of blue aliens and green skies every night - and that would be your normality.
So your dreams are heavily based on your memories and expectations, and this creates an interesting conundrum which we can explore with dream mirrors.
Let's combine the ability of an dream object to function independently with your unconscious expectations about what you look like in a dream.
This experiment enables you to literally look your unconscious in the face.
The mirror experiment is simple enough. The next time you become lucid, increase your level of awareness as much as you can then seek out a mirror and look into it.
What do you see? Do you relate to the person in the mirror? Do they move the same time that you move? Do you notice anything unusual about them?
The results, you'll find, can sometimes be scary and alarming. It's a total trip. Here's a lucid dream excerpt from the very first time I tried this experiment some years ago:
Another time, I was having a normal dream and I had something in my eye, so I went to the mirror to check it out. I was prompted to become lucid while looking in the mirror:
Perhaps not surprisingly, people have reported similar effects when taking psychedelics. Looking in a mirror (in real life) while hallucinating can reveal strange facial distortions.
I have also had positive experiences with dream mirrors... But for some reason it's the really messed up ones that stick with me to this day :)
Your conscious expectations usually have very little impact on what you'll actually see in the mirror. This is definitely an unconscious experiment in which you can examine your self-image. It can also reveal personal insecurities and self-doubts, as well as positive hopes and beliefs, projected onto the mirror image version of you.
What if you see some really messed up imagery in your lucid dream mirror?
It's intriguing to interpret the symbolism of your dream. This experiment isn't simply to freak yourself out... although I admit that's part of the fun ;)
I believe learning more about yourself can be productive, too.
For example, what if your teeth fall out when you look in the dream mirror?
One theory is that your teeth reflect anxieties about your appearance and how others perceive you. In particular, they may reflect your sense of sexual attractiveness, femininity (among women) and the consequences of getting old. Dream research found that women in menopause frequently report dreams about teeth falling out.
However, no dream analysis is ever definitive. Teeth dreams are also found to commonly symbolize power, self-confidence, diet, faith, lies and money.
Different cultures find different dream meanings, and of course there is room for variation between individuals. So while you can use a dream dictionary as a starting point, you should fill in the context of your dream, your current mind set, and also note recurring dream themes and symbols.
When you've finished examining your appearance in the dream mirror, you can try one more experiment: use the mirror as a portal to another dimension.
Sometimes, as in the dream I had below, the mirror leads exactly where you expect it - to the wall behind!
If you believe the mirror to be a gateway to another location - and truly expect that to happen, visualizing events on the other side - it can be a very fun way to teleport your awareness.
Here's another example from my dream journal:
Next time you're lucid dreaming, try the mirror experiment.
(And if you like the sound of controlling your dreams, you can learn how for free here)
Check out your reflection and consciously remember as much detail as you can for dream analysis when you wake up.
And remember that mirrors, doors, wardrobes and windows can all make useful portals to your next dream location...