The title may seem incongruous to a lot of us, it is a common fact that Hitler lost the Second World War and India did not manage to get independence until 90 more years in 1947. But to a physicist, not only does the title make sense, it is something that has been known since quite some time. The concept of the multiverse or “many worlds” was first suggested in the 1960s. The theory of the infinitesimally small, quantum mechanics, was developed by the most brilliant intellects in the 1920s. Greats like Albert Einstein, Niels Bohr, Erwin Schrödinger and Paul Dirac had racked their brains for years before coming up with a weird theory that sounded crazy at first. In fact, the quantum world is so wacky and strange that it is hard to believe that it actually works. For example, if our world existed at the quantum scale, it would be possible for a person to walk straight through a wall, have a coin that is both tails and heads at the same time and someone could even exist at more than one place simultaneously!
However, no matter how queer quantum mechanics sounds, it has been a very successful theory and in fact, all our modern day electronics, for example, flash memory and computers, would not have been developed if it were not for quantum effects. The theory has passed almost all tests that it has been challenged with. At the time when it was developed, people rejected it as being complete nonsense. Even though Einstein’s work on the photoelectric effect (the emission of electrons from a metal when light is shined onto it) helped build the foundation of the theory, he was sceptical and is believed to have famously remarked “God does not play dice with the universe” (an allusion to the fact that quantum mechanics allows one only to calculate the probability of the outcome of an event and cannot predict anything deterministically).
If one were to understand quantum mechanics, one needs to abandon all common sense and intuition. However, the most remarkable part about quantum mechanics is not the theory of itself but an interpretation of its results that leads to the conclusion that there are parallel universes that exist along with ours, thus explaining the title. This is quite mind-boggling because it means that in reality anything that can happen does happen in some universe or the other. For example, if I spin a coin and let’s say it lands as a tails then there is another universe parallel to the “tails” universe in which the coin landed as a heads. So in theory, the many-worlds interpretation of quantum mechanics suggests that there is a parallel universe with Hitler being victorious and India becoming independent in 1857. Perhaps, even one where Napoleon won the Battle of Waterloo, Columbus landed at India and maybe the Soviet Union defeated the US in a Third World War in another one of them.
Not only quantum mechanics but even the best suited contender for the theory of everything, the string theory, says that there are parallel universes. This multiverse has profound implications for philosophy, religion and of course, science. If the Bible says that God created the Universe then which one and who created the other universes? What exactly is man’s position in this multiverse? Are there even universes in which there is no life on Earth but on some other planet with different creatures ruling them? Just to think of these questions can give a headache to even the most astute and brilliant. Although, this cannot be proven with concrete experimental evidence but all mathematics and science principles do point at it. If it exists, the multiverse will revolutionise humanity and existence as we know them today. Imagine if you do not like the results of a particular event, if possible, you could just travel to (or find a way to exist in) another universe where the desired outcome occurred. The possibilities are limitless. In fact, the many-worlds interpretation also predicts that each decision that we make affects which universe we exist in. Let’s say that you are deciding whether or not to wake up one fine morning. Then, as soon as you make a decision (waking up or continuing to snooze), you actually branch out into a different universe. So, if the theory is right, which it should be if we are to believe physics, think carefully before you decide because every decision branches into a different universe and completely alters your future.