Much work has been done, particularly in Western psychology, to develop a coherent capability of interpreting dreams. This work focuses entirely on the ordinary dream-state experienced by human beings while they are sleeping. During the period of REM sleep, the mind is basically disconnected from conscious participation in the outer world, but is active with what we call dreams. Making sense out of these dreams is difficult due to the confused and disorganized way most of them are presented to the mind’s eye. It is important to recognize, that despite the coincidence in the terminology, this ordinary dream-state is not comparable to the “dream-state” that can take place through the process of the Yogic trance.
Sri Aurobindo compares the Yogic trance with the ordinary dream experience: “The latter belongs to the physical mind; in the former the mind proper and subtle is at work liberated from the immixture of the physical mentality. The dreams of the physical mind are an incoherent jumble made up partly of responses to vague touches from the physical world round which the lower mind-faculties disconnected from the will and reason, the buddhi, weave a web of wandering phantasy, partly of disordered associations from the brain-memory, partly of reflections from the soul travelling on the mental plane, reflections which are, ordinarily, received without intelligence or coordination, wildly distorted in the reception and mixed up confusedly with the other dream elements, with brain-memories and fantastic responses to any sensory touch from the physical world. In the Yogic dream-state, on the other hand, the mind is in clear possession of itself, though not of the physical world, works coherently and is able to use either its ordinary will and intelligence with a concentrated power or else the higher will and intelligence of the more exalted planes of mind. It withdraws from experience of the outer world, it puts its seals upon the physical senses and their doors of communication with material things; but everything that is proper to itself, thought, reasoning, reflection, vision, it can continue to execute with an increased purity and power of sovereign concentration free from the distractions and unsteadiness of the waking mind. It can use too its will and produce upon itself or upon its environment mental, moral and even physical effects which may continue and have their after-consequences on the waking state subsequent to the cessation of the trance.”
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 26, Samadhi, pp. 500-501