Some Random Thoughts
“Two men send their servants to bring water at the same time and cause them to meet. Unaware of the plan, the servants view the meeting as random.” With this story dating to 400 B.C., Democritus explained his vision of a deterministic world. In his telling, randomness could not exist and was simply a lack of knowledge rather than an actual phenomenon. If one had a “vast intelligence” like the one of Laplace’s demon, a thought experiment published in 1814, one could determine every action taken or to be taken.
The idea of a fully deterministic world held sway in the West until very recently. While tools to describe the unknown were developed in the 16th century when Italian mathematicians began to formalize the odds associated with various games of chance, it was not until the early part of the 20th century that the formal analysis of randomness and the mathematical foundations for probability were introduced, leading to their axiomatization in 1933. This work combined with the development of quantum mechanics in the mid-1920’s finally put to bed the fully deterministic worldview. Reality at its most basic layer turns out to be entirely probabilistic in nature.
Combining the understanding that reality is probabilistic at the sub-atomic scale with the Newtonian mechanics we experience at the macro-scale remains a challenging area of thought. Two interesting examples of areas where ideas about randomness are being applied together are in biology and computer science:
1. A recent discovery, published in Nature, showed that mutations, a key element in the evolution of species and the development of diseases, previously thought to occur randomly as DNA replicates, may not happen so haphazardly after all. By looking to see whether mutations happened evenly between gene and non-gene regions of a genome, scientists discovered that Arabidopsis thaliana, a common roadside weed and major model organism of plant biology, can shield the most “essential” genes in its DNA from changes while leaving other sections of its genome to accumulate mutations. This unexpected finding thus described both random and non-random events influencing the development of the genome, and open a new way to think about mechanisms of tumorigenesis as well as ways to engineer improved processes for directed evolution.
2. Randomness is vital for computer security. The ability to generate random strings of numbers and letters makes possible secure encryption that allows people to store data or communicate secretly even if an adversary sees all coded messages. In these instances, the more random the string, the more secure the data. However, short of having the encryption key hidden in your subconscious, creating truly random numbers is surprisingly hard. Especially if all you have available to do it is digital hardware and deterministic software. Both are designed to behave predictably. Therefore, hardware and software designers, trying to find unpredictability, have to look outside of their normal operating environment to find it. Software typically seeks to use external events (user’s mouse clicks, Ethernet packet arrival intervals, or atmospheric noise) to create randomness. There are challenges in finding enough of these seemingly random events, however, to satisfy what is needed for all encrypted operations. Various groups are working at creating high-quality randomness from low-quality (but abundant) sources. And quantum computing looms as a potential solution, though when it will be ready for broad-based commercial use remains very unclear.
It is hard to think or write about anything else this week other than the terrible ongoing events in Ukraine. Russia’s unprovoked attack is a stark reminder that seemingly stable liberal democracies are not impervious to the frightening descent into war and all its attendant randomness. We stand with the people of Ukraine and hope that the world will act together to reject Putin’s deterministic attempt to violently and illegally impose on their sovereignty and freedom.