What Is Randomness?

If chance is defined as an event produced by random motion without any causal nexus, I would say that there is no such thing as chance.

- Boethius, The Consolation of Philosophy

Podcast of the Day

Melvyn Bragg and his guests discuss randomness and pseudorandomness. Randomness is the mathematics of the unpredictable. Dice and roulette wheels produce random numbers: those which are unpredictable and display no pattern. But mathematicians also talk of 'pseudorandom' numbers - those which appear to be random but are not. In the last century random numbers have become enormously useful to statisticians, computer scientists and cryptographers. But true randomness is difficult to find, and mathematicians have devised many ingenious solutions to harness or simulate it. These range from the Premium Bonds computer ERNIE (whose name stands for Electronic Random Number Indicator Equipment) to new methods involving quantum physics. Digital computers are incapable of behaving in a truly random fashion - so instead mathematicians have taught them how to harness pseudorandomness. This technique is used daily by weather forecasters, statisticians, and computer chip designers - and it's thanks to pseudorandomness that secure credit card transactions are possible.

Listen to the In Our Time episode on Random and Pseudorandom

Video of the Day

Short Article of the Day

Randomness is powerful. Think about a presidential poll: A random sample of just 400 people in the United States can accurately estimate Clinton’s and Trump’s support to within 5 percent (with 95 percent certainty), despite the U.S. population exceeding 300 million. That’s just one of many uses.

Randomness is vital for computer security, making possible secure encryption that allows people to communicate secretly even if an adversary sees all coded messages. Surprisingly, it even allows security to be maintained if the adversary also knows the key used to the encode the messages... But it turns out some – even most – computer-generated “random” numbers aren’t actually random...

Continue reading Zuckerman & Chattopadhyay's article: How random is your randomness, and why does it matter?

Further Reading

Chance and randomness are closely related. So much so, in fact, that to say an event happened by chance is near enough synonymous in ordinary English with saying it happened randomly. This suggests that ordinary speakers would by and large endorse this Commonplace Thesis:

(CT) Something is random iff it happens by chance.

The Commonplace Thesis, and the close connection between randomness and chance it proposes, appears to be endorsed in the scientific literature too. So we see authors moving smoothly between calling something ‘chancy’ and calling it ‘random’...

However a number of technical and philosophical advances in our understanding of both chance and randomness open up the possibility that the easy slide between chance and randomness in ordinary and scientific usage—a slide that would be vindicated by the truth of the Commonplace Thesis—is quite misleading...

Continue reading the Stanford Encyclopedia of Philosophy article on Chance versus Randomness by Antony Eagle

Related Topics

Logic | Luck | Mathematics

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