Buddhism speaks of six, seven, or eight aspects of consciousness. It speaks first of the ground or basic consciousness, which has a global, general knowledge that the world is there and that I exist. Then there are five aspects related to the five sensory experiences: seeing, hearing, smelling, tasting, and touching. The seventh aspect is mental consciousness, which associates abstract concepts to the first six aspects. Sometimes there is considered to be an eighth aspect of conscious-ness that is related to afflictive mental states that distort reality (hatred, craving, etc.). But even more fundamental than all these states and aspects is primary consciousness, what is called the continuum of the luminous fundamental consciousness.
In Buddhism, the matter/consciousness duality, the so-called mind-body problem, is a false problem given that neither of them has an intrinsic, independent existence. According to some Buddhist teachings that analyze phenomena at a more contemplative level, the primordial nature of phenomena transcends notions of subject and object or time and space. But when the world of phenomena emerges from primordial nature, we lose sight of this unity and make a false distinction between consciousness and the world. This separation between the self and the non-self then becomes fixed, and the world of ignorance, samsara, is born. The birth of samsara did not happen at a particular moment in time. It simply reflects at each instant, and for each of our thoughts, how ignorance reifies the world.
Buddhism’s conception is thus radically different from Cartesian dualism, which postulates on one side a truly existing solid material reality and, on the other side, a completely immaterial consciousness, which cannot have any real connection with matter. The Buddhist analysis of phenomena recognizes the lack of intrinsic reality of all phenomena. Whether animate or inanimate, they are equally devoid of autonomous, ultimate existence. Thus, a merely conventional difference exists between matter and consciousness.
Because Buddhism refutes the ultimate reality of phenomena, it also refutes the idea that consciousness is independent and exists inherently, just as much as it refutes that matter is independent and exists inherently. This fundamental level of consciousness and the world of apparent phenomena are linked by interdependence, and together they form our world of thought and the exterior physical reality is a mere illusion. There’s only one reality or, rather, only one lack of intrinsic reality! Buddhism does not adopt a purely idealist point of view or argue that the outer world is a fabrication of consciousness. It just points to the fact that without consciousness, one cannot claim that the world exists because that statement already implies the presence of a consciousness.
This might sound puzzling, but it resembles the answer given by some cosmologists when asked what was there before the Big Bang. They say that this question does not make sense because time and space began with the Big Bang. Likewise, anything we can ever say about the world, the brain, and even consciousness begins with consciousness. Even the question, “But couldn’t a world totally deprived of life and sentience exist on its own?” as well as any answer that you might like to give to this question—all of this presupposes consciousness. Of course, it would be foolish to deny the existence of lifeless worlds because most planets are indeed lifeless, but without consciousness, in a way, there is no question, no answer, no concepts, no “world” as an object of experience.
Read more, including Wolf Singer’s (the neuroscientist) reply in:
Beyond the Self: Conversations between Buddhism and Neuroscience - MIT Press 2017