The quantum theory states that very tiny particles exist in many *states* at once until an observer measures them to determine their position. In other words, no one knows that you exist yet unless you’re perceived (seen, touched, or any sort of empirical encounter). However, there’s another controversial interpretation of quantum physics that states that *nothing* actually exists in many states at once — the observer just isn’t sure which state it is in. In this case, you will only exist only if you’re perceived by another, or else, you *don’t*. This controversial observer-centric of quantum physics is called *Quantum Bayesianism*, also known as *QBism*.

**Related media: The Quantum Experiment That Broke Reality**

**A Quantum Deck Of Cards**

This tantalizing yet controversial interpretation of the quantum theory was conceived by quantum theorist Christopher Fuchs.

Here’s a hypothetical analogy to explain this quantum phenomenon:

Think of the quantum world as a deck of cards, (yes, we’re playing quantum poker). The traditional *Copenhagen* interpretation goes like this: Let’s say the dealer puts forth a card face down, *probably* speaking, that particular card could simultaneously be any of all the 52 cards at once. From the traditional interpretation of quantum mechanics, that’s a *superposition*; and the mathematical formula that describes all of those states is called a *wave function*. Only when you take a look at that card will you know for sure what that card is — technically called *collapsing the wave function*.

What if all the cards were picked leaving you with only the ace of spades and the queen of diamonds; you then choose the ace of spades, this changes the state of the remaining card so it becomes the queen of diamonds. This relationship, where the state of one card changing the state of the other is a concept technically known as *entanglement*.

**The Quantum Explanation**

Here’s how QBism explains our quantum poker:

If the dealer puts forth a card face down, you know that that card has a 1 in 52 chance of being any one of the cards in the deck; a 1 in 4 chance of being any one of the *suits*; and a 1 in 2 chance of being either *black* or *white*.

According to QBism, that’s all a wave function: the quantum varying range of probabilities. When the dealer turns the card, let’s say it’s an ace of spades, you now get to know what that card is, that it’s a 100 percent chance of being an ace of spades. The wave function is now *updated*, not collapsed. In a similar way, if two face-down cards remain on board, each one has a 1 in 2 chance of being either card — having a relationship of probability, this is no *spooky* quantum phenomenon. In other words, QBism implies that quantum mechanics is just a probability of reality, and not reality itself.

That’s just how cards work, if you’re really into poker. This hypothetical version of quantum mechanics sounds pretty arbitrary. But QBism holds the unique view of varying probabilities in the quantum world. The chance of one thing being accurate doesn’t matter as much as the observer’s uncertainty. This raises the argument that QBism is all about subjective personal experience; in other words, it seems like reality only exist in the mind of the observer, and thus two different people can perceive two different realities. Critics say science is objective, reality is reality, whether you’re present or not.

**Can You Spell Reality Without An ‘R’?**

This phenomenon was explained better by N. David Mermin in an article he published in *Nature*:

“Although I cannot enter your mind to experience your own private perceptions, you can affect my perceptions through language. When I converse with you or read your books and articles in Nature, I plausibly conclude that you are a perceiving being rather like myself, and infer features of your experience. This is how we can arrive at a common understanding of our external worlds, in spite of the privacy of our individual experiences.”

By now, we’ve confused you enough with QBism: that’s what it does, raising a lot more question than it answers. If quantum mechanics doesn’t describe an external reality, what does? Fuchs himself says that might be the wrong question.

“Usually we think of the universe as this rigid thing that can’t be changed,”he told Quanta Magazine. “Instead, methodologically we should assume just the opposite: that the universe is before us so that we can shape it, that it can be changed, and that it will push back on us. We’ll understand our limits by noticing how much it pushes back on us.”

Dear friends, that’s how bizarre the quantum world is. We’re sorry if you thought we think you don’t exist. After all, how could we know?

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*Written by:* *Nana Kwadwo**,** Sun, May 05, 2019.*

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