In terms of determining what world one is within is their conscious sensory perception.
If your senses don't consciously perceive the waking world then you are perceiving another world.
This definition of world is whatever one's senses are actively consciously perceiving.
While you may still have memories of the waking world you have no conscious sensory perception of it what so ever when within the other world.
"Lucid dreamers are conscious of the absence of sensory input from the external world; therefore, on empirical grounds, they conclude that they are asleep. "
"Upon awakening, they report having been totally in the dream world and not in sensory contact with the external world. "
What Does it Mean to Not Perceive a World?[]
If you don't consciously perceive it then it is as if it does not actively exist.
While you are aware of the existence of the other world of which you are in as long as you are unable to consciously perceive the world you are essentially not there.
How do you Enter the Dream World?[]
The obvious answer is of course to enter a lucid dream state but to go into further detail on how to fully enter the world of dreams one must be completely cut off from perceiving the waking world.
This means that while consciously aware of the dream world you are completely unable to perceive the waking world that you know you are physically in with any of your senses.
Keeping a dream journal to record dreams and purposefully waking up in the middle of sleep and then going back to sleep are simple ways of entering a lucid dreaming state.
What is the Purpose of this Page?[]
"To the functional systems of neuronal activity that construct our experiential world (model), dreaming of perceiving or doing something is equivalent to actually perceiving or doing it. ".
"The evidence is clear: lucid dreaming is an experiential and physiological reality"
Our neuronal activity does not differentiate depending on whether or not someone is in the dream world or the waking world.
While we perceive the two worlds separately, one as the true reality and one as our imaginings, our neuronal activity treats both equally as real.
On the physiological level the world of dreams is very real, and this is what makes the dream world so fascinating.
