Sleep vs Slumber
Sleep and Slumber are the two states of rest the mind and the body of a human being enjoy. Both these states are said to be different from each other in character and nature. Sleep is the primary state of rest whereas slumber is said to be the supreme state of rest.
One of the main difference between sleep and slumber is that sleep is normally accompanied by dream where as slumber is the state of the mind that is not accompanied by dream. In short it can be said that sleep is qualified by dream whereas slumber is not qualified by dream.
In sleep you would have the sub-conscious mind inactive whereas in slumber the sub-conscious mind remains active. It is believed that the sub-conscious mind becomes one with the Supreme Bliss in slumber. This is the reason why slumber is often called as ‘sleep’.
Philosophers have classified the states of the mind into four, namely awakening, sleep, slumber and the Supreme. In the awakening state of mind the person is conscious of what he does. During sleep he witnesses dream. In the slumber state of the mind his sub-conscious mind remains active and becomes one with the total consciousness. In the Supreme state of the mind, he attains the highest vision.
Hence it is believed that sages often attain the Supreme state of the mind. The state of slumber is often recognized as the state that is very close to the Supreme state of mind in the sense that it experiences the state of Supreme Bliss bereft of dreams.
The person who is in slumber often says that he slept so well that he knew and dreamt nothing during his sleep.