There is practice and experience, and there is expression in words. The formulation of experience in words creates the opportunity for transmission of knowledge obtained from a specific person, and makes his experience accessible for application by other people. Knowledge of this type relates to the purely practical questions and usually amounts to advice on how and what to do, in order to obtain the necessary result. This enjoys enormous popularity in our time – books with practical advice sell well, and the Internet is full of videos with advice for all occasions in life.
There exists knowledge in which the experience of many people is combined, and certain patterns are extracted of how everything is constructed. This is already knowledge that is more general, and is not entirely practical. It helps to understand something not so much about the subject of experience, as much as how it is obtained in general and about the people who come to it. In the framework of the spiritual Way, practical knowledge, for example is the description of efforts in self-awareness by those who have applied them for a rather long time, and can speak of the obstacles and traps they encountered. This is the living experience of one person who has attained something and is sharing it with others. More general knowledge in this example would be the compilation of experience of dozens or hundreds of seekers performing the same practice, and the discovery of patterns of what happens in general in it with a person, the showing of its stages, and so forth.
Experience may be laid out with the use of various forms – either in the form of direct instructions, or in the form of discussions on a topic, or even dialogues between an author and listeners. In fact, it is this form of transmission of experience that all modern Advaitis prefer. But there is still another form of making sense of the experience of another, as a rule – the creation of various types of theories. Or, to put it more simply, the creation of a philosophy. The experience of the development of awareness can provide someone with a reason to reflect on the nature of consciousness and about its source. Here the experience becomes the point of departure for the beginning of philosophizing – that is, for the construction of a system of claims that must not be contradictory from the perspective of logic, but not only -- in theory, it should lead to discovery of new knowledge.
In the distant past, philosophy took the place of almost all forms of existing sciences, since a person was technically limited to the possibilities of studying himself and the surrounding world. The basis for his knowledge was the mind with its reasonings and logic, and out of this was born numerous systems describing the world, and not only the world. God also became a subject of research, which rarely relied on people’s own experience and often on sacred writings. In the West, under Christianity, theology was thus developed, and in the East, thus new forms of religions emerged.
Advaita-Vedanta, with which the story of modern Advaita begins, arose as a pure philosophy. Advaita means the absence of duality, the claim that the individual soul (jiva) and God (Brahman) have the same nature, or more simply put, are practically the same thing. Besides, in the original philosophy of Advaita-Vedanta, it was claimed that the world is illusory, and only God is real, and all of this was extracted from the Upanishads, which are part of the Holy Vedas. Essentially, Advaita was form as an interpretation of certain places in the Upanishads, and the interpretation was rather revolutionary. The Upanishads, in turn, is a collection of mystical texts which in all likelihood reflected the mystical experience of their creators.