Throughout history, people have doubted about many aspects of reality and some have even questioned reality itself. One of the best examples, though not the earliest is illustrated by René Descartes in his Evil Demon concept. Descartes hypothesized the existence of a powerful and deceitful entity whose sole purpose is misleading him in every aspect. Therefore, the ‘demon’ presented Descartes with a complete illusion of the external world, including other people and their minds. The entire sensory input would then be a continuously fed deception yet felt as reality.
This experiment, however interesting, was regarded simply as an odd quirk of the imagination. Until the concept of quantum realism came along. Despite the name, this idea centers around the same principle, only it ascribes the role of the illusion generator to something much more mysterious than an utterly malevolent demon –quantum mechanics.
Our everyday world is governed by physical realism. Picture an apple.
We feel it. It has weight and is subject to gravity, thus it falls down from the tree. It inevitably obeys the laws of mechanics which we all subjectively know through observation. Only when we leave the realm of the easily observable and start viewing things on the subatomic scale, the weirdness begins. Welcome to the quantum world. Things work differently here. Particles pop in and out of existence and they can exist in multiple places at the same time. You’ve surely heard of Schrödinger’s Paradox, although explaining the baffling principles of quantum mechanics with cats might seem an odd choice.
To those of us used with physical realism, the quantum world seems like a mystical wonderland. Quantum physics can neither be explained nor predicted through conventional, Newtonian physics. It seems very odd that our visible world is capable of generating such a quirky one if we look really, really close. Modern physics has been struggling with these inconsistencies for the past century and these struggles have given rise to the concept of quantum realism (QR). Here it goes: