The Schrodinger’s cat paradox is as follows: a cat is placed in a sealed box. Inside a gun is pointed at the cat (and the trigger is then connected to a Geiger counter next to a piece of uranium). Normally, when the uranium atom decays it sets off the Geiger counter and then the gun and the cat is killed. The uranium atom can either decay or not.

So we have to add the two possibilities, adding the wave function of the decayed atom with the wave function of the intact atom. But this means that, in order to describe the cat, we have to add the two states of the cat. So the cat is neither dead nor alive. It is represented as the sum of a dead cat and a live cat!

Einstein believed in “objective reality”. And yet this bizarre interpretation lies at the heart of modern civilization. Without it modern electronic (and the very atoms of our body) would cease to exist. In or ordinary world, we sometimes joke that it’s impossible to be “a little bit pregnant”. But in the quantum world, it’s even worse. We exist simultaneously as the sum of all body states: unpregnant, pregnant, a child, an elderly woman, a teenager, a career woman, etc.

The founders of the quantum theory believed in the Copenhagen School, which said that once you open the box, you make a measurement and determine if the cat is dead or alive. The wave function has “collapsed” into a single state and common sense takes over. The waves have disappeared, leaving only particles. This means that the cat now enters a definite state (either dead or alive) and is no longer described by a wave function.

When guests would come to Einstein’s house, he would point to the moon and ask, “Does the moon exist because a mouse looks at it?” In some sense, the answer of the Copenhagen School might be yes.

One minority point of view is that there must be “cosmic consciousness” pervading the universe. Objects spring into being, when  measurements are made, and measurements are made by conscious beings.

Some like Nobel laureate Eugene Wigner have argued that this proves the existence of God or some cosmic consciousness. He wrote, “It was not possible to formulate the laws [of the quantum theory] in a fully consistent way without reference to consciousness.” In fact, he even expressed an interest in Vedanta philosophy of Hinduism, in which the universe is pervaded by an all-embracing consciousness.

Another viewpoint is the “many worlds” idea, which states that the universe simply splits into half, with a live cat in one half and a dead cat in the other. This means that there is a vast proliferation or branching of parallel universes each time a quantum event occurs. Any universe that can exist, does. This means that there is a parallel world in which the Nazis won World War II, or a world where the Spanish Armada was never defeated and everyone is speaking in Spanish.

Nobel laureate Frank Wilczek says, “We are haunted by the awareness that infinitely many slightly variant copies of ourselves are living out their parallel lives and that every moment more duplicates spring into existence and take up many alternate futures”.    ~ PHYSICS OF THE IMPOSSIBLE by MICHIO KAKU (Pg 243, 244)