According to the Quantum Theory, at the fundamental level, the concept of a particle becomes blurred with the concept of a wave, or rather a probability wave. Ervin Schrödinger, the creator of the mathematics of Quantum Mechanics, calls the Vedantic identity of Brahman and Atman “the quintessence of deepest insight into the happenings of the world”. His famous thought experiment of the “Schrödinger’s Cat” illustrates the basic probabilistic nature at the quantum level. A cat is sealed in a closed box/chamber with a flask of poison, a Geiger counter and a radioactive source. In an hour, there is a 50% chance that the source will emit radiation. If it does, the Geiger counter will detect it and cause the flask to break, releasing the poison and killing the cat. If not, the cat will still be alive. At this point, since the box is sealed, we don’t really know the state of the cat – the probability of the cat being alive or dead of 50%. It only becomes 100% alive or dead when the conscious entity, i.e. an observer, interferes with the experiment by opening the chamber for examination. Please note: It is not that the cat died or lived when the observer observed or that the observer observed the dead or alive cat, but rather the state of the cat got defined as “the cat died when the radiation was emitted releasing the poison” or “the cat lived as the radiation was not emitted” when the observer observed. The whole basis of the Quantum Theory is this unpredictability or a quasi-state of existence (or non-existence) at the basic fundamental level and the effect of ‘observation’ defining the ‘observed’. These have been discussed mathematically and in physics starting with the scientists like Schrödinger and Heisenberg (the latter in his uncertainty theorem). At that fundamental level, the boundary between pure science and philosophy starts to blur.
The philosophy behind this observer or ‘seer’ defining the observed or the ‘seen’ has been explained in the Drishti-Srishti Vada as well as the commentaries by Sri Gaudapada (Sri Shankaracharya’s guru) on the Mandukya Upanishad known today as the Gaudapada Karika. Our dream state is one of the finest example of the possibility of the proposition of Drishti-Srishti Vada. While dreaming, the world within the dream seems real and separate from you the dreamer. But when you wake up from the dream you realize that the world in the dream was just a projection of your mind and it existed because of you the dreamer or the ‘seer’ or the observer existed. ‘Waking up’ from the waking state to state beyond will let you realize that the world in your waking state also existed because your awareness existed; and you perceived it through your individual you, your attributes present over the pure consciousness or the absolute awareness.