Kylie Lang, Lucia Lopez, Michaela McGovern
Professor Rodriguez-Contreras
Science Forward
September 22, 2016
The Search for Randomness
Does randomness exist? This was the question Dr. Persi Diaconis explored at a lecture
on September 15, 2016. The City College of New York alum held the speech on the campus of
his alma mater. After attending the City College of New York, Dr. Diaconis studied math and
statistics at Stanford University. Also in his repertoire is his ten-year professional magician
career and a MacArthur Fellowship.
When we think about fair and random ways to make a choice between two things, one of
the most common methods is tossing a coin. Even the National Football League uses this
method to decide which team gets the ball first. Dr. Diaconis challenges the idea that tossing a
coin is random and instead argues that the results happen due to physics. He generalizes a
normal toss as being one foot high at a controlled speed of 5.5 mph, making 15 to 20 revolutions
before landing. However, not everyone throws coins the exact same way each time. There are a
number of factors that dictate the result of a coin toss which are often disregarded and therefore
thought to be a random occurrence.
Most people neglect air resistance as a factor that limits randomness although it can be a
critical factor depending on the location. There’s also different biases such as bouncing or
spinning on a surface. Dr. Diaconis takes into consideration that catching a coin in the air does
make it more accurate since it does not bounce or spin when it’s dropped. While we only see
tossing a coin as having two options, there’s a third possibility which is often overlooked. A
coin can land on its edge with a probability of 1 out of 6000, yet that is often regarded as an
outlier occurrence.
Dr.Diaconis goes on to name a few more examples which are misinterpreted as being
random. For example, throwing darts seems like it can be random with the thin rows of black and
white sections; however, there are factors such as the skill of the person throwing it which can
produce a less than random result. Through calculations, the needed angle of trajectory can be
found in order to hit a specific spot. This goes back to his previous statement about how nothing
is really random and can be categorized as a result based on physics.
His prior history in the magical entertainment field led him to an analogy about
randomness in shuffling playing cards. Although shuffling is believed to make a new deck with
a random order, what it really does is keeping it in an ordered disorganization. Each shuffle may
bring the deck order to a closer definition of random, but theoretically it would take an infinite
amount of shuffles for it to be considered random. Therefore, Dr. Diaconis concludes that
randomness is an unattainable concept in which he is determined to search for.