Ian G. Barbour in Religion in an Age of Science explains that one of the key distinctions between classical physics and quantum theory has to do with epistemological separation between the observer and the observed: “In short, we do have to abandon the sharp separation of the observer and the observed that was assumed in classical physics. In quantum theory, the observer is always a participant” (Barbour, 100). According to quantum theory, the act of observation somehow affects the thing observed, such that it is no longer appropriate to think of the object of observation in terms of an independent physical reality. It is now a fact of modern scientific investigation that observer and observed are involved in some form of cause and effect relationship: “Length, mass, velocity, and time, once thought to be objective, primary properties of objects in themselves, are now known to be relative to the observer” (Barbour, 111). If an animal senses that it is being aimed at by a hunter’s rifle, the animal will move. The hunter’s position in relation to the animal affects the behavior of the animal in the same way as the scientist’s observation affects the nature of the observed phenomenon. The scientist, like the hunter, is dealing with a moving target rather than a static entity. Furthermore, the fact that the observer and the observed in science are somehow interconnected suggests that they are both constitutive parts of the same system: “Quantum physics points to the unity and interconnectedness of all events. Particles are local disturbances in interpenetrating fields. In relativity, space and time form a unified whole, and matter-energy is identified with the curvature of space” (Barbour, 118).
The scientific finding of an interconnected whole is congenial to the non-dual metaphysics of Advaita Vedanta. In Knowledge and Liberation in Classical Indian Thought, Chakravarthi Ram-Prasad describes a “primal misunderstanding” whereby the individuated consciousness misunderstands the relationship between itself and the objects of experience: “Consciousness commits the primal misunderstanding of taking itself to be a distinct ego individuated by the body and the internal and external apparatus (mind and senses), which things it superimposes on its own nature” (Ram-Prasad, 185). Following the logic of this primal misunderstanding, the mind and body are appropriated by the self in what amounts to an objectification of the pure essence of consciousness: “It is the condition of unliberated life that the self is superimposed on body/mind (through identity) and objects (through relationships)” (Ram-Prasad, 182). According to Advaita Vendanta, ultimate reality is consciousness as such, or “pure consciousness,” which must be distinguished from the subjectivity associated with individual identity. According to Ram-Prasad, pure consciousness is “the unconditioned reflexivity that remains at the end of all stripping away of contingent individuation” (Ram-Prasad, 168). The Advaitic concept of pure consciousness, or the “self,” is pre-reflexive, so by the time consciousness assumes the shape of a specific thought, that is to say, as soon as it acquires an object of knowledge, it is already individuated, and can therefore no longer be understood as “pure.” The nature of the Advaitic concept of the self is therefore reflexivity as such, understood as the general process whereby consciousness individuates itself, not as the specific instances of that reflexive process when actual objects of knowledge come to be: “Consciousness occurs as a locus of reflexive awareness, individuated by parameters that seem to come into existence prior to the occurrence of reflexivity. So, looked at in terms of what consciousness is, it is not the specificity of each locus which is striking but the generality of its (consciousness’s) nature as reflexive (to be sure, in individuated loci)” (Ram-Prasad, 165).
The findings of modern physics seem to suggest that scientific observation merely reveals possibilities, not conclusive certainties, and in Advaita Vedanta the superimposition of the self onto the mind, body and objects in the world means that bodies, minds and objects are merely possible instances of the underlying general reflexivity common to all forms of consciousness. As Barbour explains, the wave-particle paradox, whereby the usually wave-like behavior of an electron inexplicably becomes particle-like when placed under direct observation, indicates that nature has an indeterminate character, such that through scientific observation we only capture one of several possible outcomes: “Observing consists in extracting from the existing probability distribution one of the many possibilities it contains. The influence of the observer, in this view, does not consist in disturbing a previously precise though unknown value, but in forcing one of the many existing potentialities to be actualized” (Barbour, 103). Therefore, we might say there is some “hidden variable” at work which favors the actualization of one specific potentiality over another, and as Barbour explains, for some authors such as William Pollard, this hidden variable is God: “God, [Pollard says], determines which actual value is realized within the range of a probability distribution. The scientist can find no natural cause for the selection among quantum alternatives; chance, after all, is not a cause” (Barbour, 117). While the idea of God acting in the world in this way remains strictly hypothetical, and decidedly monotheistic, the mystery surrounding the hidden variable does incite religious speculation. Setting God aside, the notion of self in Advaita Vedanta provides another possible explanation for the hidden variable phenomenon. The self, as we have seen, is the general reflexivity that superimposes itself onto the mind, the body and objects in the process of identity formation. The self, we might say, determines which among a range of possible identities to actualize in the form of an individuated consciousness. It could therefore be argued that it is the Advaitic self that determines which actual value is realized with respect to the position of the electron in the scientific experiment. Viewed in this way, it is consciousness that “decides” the particle-like behavior of the electron through the process of observation, even though the electron is known to otherwise behave like a wave.
All of this is quite difficult to fathom, and Barbour rightfully points out that, even in the face of a paradox, it is important to remain coherent: “Coherence remains an important ideal in all reflective inquiry, even if it is qualified by acknowledgment of the limitations of human language” (Barbour, 101). While the monotheistic God or the Advaitic self might constitute interesting hypothetical explanations for what is otherwise outside the reach of our comprehension, what can be affirmed with a greater degree of certainty is that the existing models and categories of human thought have proven to be inadequate. As Barbour recalls, “In the eighteenth century, Kant and his successors held that the structures of time, space, and causality are categories of human thought, which we impose on nature; we can never know things as they are in themselves” (Barbour, 114). As human beings inhabiting this earth, we are perhaps too intimately involved with nature to be able to describe it objectively as it really is.
 Barbour, Ian G. (1990). Religion in an Age of Science: The Gifford Lectures 1989-1991 (Vol. 1). New York: Harper Collins Publishers.
 Chakravarthi, Ram-Prasad (2001). Knowledge and Liberation in Classical Indian Thought. Hampshire: Palgrave.