The science of Raja Yoga utilizes Asana and Pranayama, but simplifies both of these down from the complexity and intensity practiced in Hatha Yoga. The goal of Raja Yoga is to gain control over the mind and what is called the “mind-stuff” (chitta) to bring it to a state of unmoving tranquil calm, such that the mind is totally detached from the physical body and the material world and is thereby able to achieve spiritual realization. Just as the practitioner of Hatha Yoga works to bring the power of immobility to the body, the practitioner of Raja Yoga wants to do the same for the Mind. The practitioner of Raja Yoga recognizes that there is a link, a continuity and a relationship between the mind and the body, and thus, utilizes Asana and Pranayama to ensure the body and nervous system are under control. Other elements of Raja Yoga are then added to focus, train and concentrate the mental power, and then exercise mastery over the nervous sheath and the physical sheath.
Historically, Western scientists have had difficulty accepting the reality of the mind or the soul. Sri Aurobindo observes: “Modern Science and psychology have … tried to establish that there is no separate entity as mind or soul and that all mental operations are in reality physical functionings.” More recently, with the rise of disciplines such as Quantum Physics, there has been a serious change in the standpoint of Western researchers, who now are not only willing to recognize a link between mind and body, but are even ready to declare that it is consciousness that is the reality that creates energy, which then creates physical being. Thus, we are beginning to see a convergence between modern day scientists in the West and the ancient seers and sages who practiced Yoga, and in particular Raja Yoga. Of course, for the vast majority of people, the dependence of the mind on the body is the “reality” and there are few who experience the separateness and dominance of the mind over the body. To the extent that people ordinarily do this, they in many cases talk about the power of suggestion, the power of prayer, the power of positive thought and emotion to make things happen both on the individual level and in the world. In the abstract there is truth in these assertions, but for most people, who have not undertaken the discipline to actually focus and concentrate the mental or spiritual power, the actual impact remains small.
The practice of Raja Yoga provides a scientific methodology to achieve this real power and exercise mastery over the body, life and mental processes, such that spiritual realisations can occur.
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 28, Rajayoga, pg. 514