Words by Sarah de Launey, edited by Nicola Simcock

Whether you master the riffle or, like me, drop half the cards on the floor and clumsily mix the rest on the table, you know that shuffling is the first step of every card game. This ritual adds an element of chance to the game (and thwarts any attempts of cheating and trickery!) by making sure players can’t predict the cards that are dealt. Anecdotally, we say that 7 imperfect shuffles are enough to randomize a deck, where every configuration is equally likely. Having cards in a random order means every player has an equal chance of getting the ace of clubs and so, adds the element of chance and fairness into the game.

In a randomized (really well shuffled) deck, finding 10 clubs in a row is a perfectly valid random sequence. But try dealing that in a poker game and you’re likely to be met with some serious eyeballing. A row of clubs *feels* too much like a pattern to be random. Humans are notorious for constantly searching for meaning and order in everything, often creating it where it doesn’t actually exist. This is so common it even has a name: apophenia. Think of constellations in the night sky, faces in the clouds… and of course, gambling. Hardened gamblers will swear that they will win the jackpot after a run of ‘bad luck’. This is called the Gambler’s Fallacy: ‘Gambler’ because of its roots in games of chance and ‘Fallacy’ because we know that past events do not change the probability of future events.

No matter how many clubs we’ve had in previous games, when we draw a card out of a randomized deck, there is an equal probability of drawing any of the 52 cards. A one in 52 chance of drawing the trump card adds an element of chance because it is unpredictable. At least… it is unpredictable to muggles.

A magician is able to predict that one-in-52-chance card every time.

So how do they do it? I can’t say. Partly because I’m afraid of the magician’s wrath, mostly because I don’t know. You can however get an idea of how this could be done by watching David Cushing’s SciBar talk on card tricks and the mathematical principles behind them (https://www.youtube.com/watch?v=AiCOqdd2zMI&t=2861s).

What I can tell you is that magicians know where your card is and that they use applied mathematics, as well as magic (obviously), to pick the right card. The important bit of the trick is always being in control. Magicians know how to control the initial conditions of the deck and the formulaic manipulation of cards, without you suspecting a thing! This makes the outcome predictable, but only to the mathematician… I mean… magician, who has the information.

When we play cards, play the lottery or flip a coin, the outcome is unpredictable to us. Even if we know the initial conditions, our little brain can’t compute all the external forces that cause the outcome. Let’s take the coin flip. We can see which face the coin starts on and we know there is a 50/50 chance of the coin landing on heads or tails. What we can’t evaluate is everything that happens in between: the force of the throw, the subsequent height and spin of the toss, air resistance and wind speed, the sponginess of the carpet… all these factors will affect the result. But what if we could calculate all these factors?

If we did calculate these factors, then yes, it’s likely we could predict the outcomes we usually consider random. We would be able to see into the future, meaning everything is the logical result of a series of initial conditions and external forces. Ultimately, what we perceive as choices, are just the logical result of specific circumstances.

This idea is not new – it’s called determinism: the idea that every event is the direct result of previous events and conditions. It’s the complete opposite of randomness. Determinists say that, despite how complicated we are, we are still just machines following the same pattern of cause-and-effect and so logically, we lack real free will.

But not everyone agrees. Voltaire was a vocal champion of free will, saying “Each player must accept the cards life deals him or her; but once they are in hand, he or she alone must decide how to play the cards in order to win the game.”

Even further back, in 300 BC, Epicurus stated that the smallest building blocks of the universe would tear around so fast that they would sometimes swerve from their path, creating new causal chains. This is actually not so far off how we think about the universe today.

We currently think that true randomness does in fact exist on the smallest scale we know of, the quantum scale. On this scale, just like Epicurus said, the smallest building blocks of matter behave unpredictably because their properties do not allow them to be measured. While we can describe the probability of different outcomes, we will never be able to predict them.

So back to our question: could we predict the future if we knew the initial conditions and could calculate all the external forces? In short, no. Though we could perhaps one day predict the probability of a multitude of possible futures.

So maybe life is like a game of cards. We can predict the probability of winning but never really know how the game will unfold until we play.