Brains, computation and thermodynamics: A view from the future?

by Ashutosh Jogalekar

Rolf Landauer who discovered a fundamental limit to the efficiency of computation. What can it tell us about human brains?

Progress in science often happens when two or more fields productively meet. Astrophysics got a huge boost when the tools of radio and radar met the age-old science of astronomy. From this fruitful marriage came things like the discovery of the radiation from the big bang. Another example was the union of biology with chemistry and quantum mechanics that gave rise to molecular biology. There is little doubt that some of the most important future discoveries in science in the future will similarly arise from the accidental fusion of multiple disciplines.

One such fusion sits on the horizon, largely underappreciated and unseen by the public. It is the fusion between physics, computer science and biology. More specifically, this fusion will likely see its greatest manifestation in the interplay between information theory, thermodynamics and neuroscience. My prediction is that this fusion will be every bit as important as any potential fusion of general relativity with quantum theory, and at least as important as the development of molecular biology in the mid 20th century. I also believe that this development will likely happen during my own lifetime.

The roots of this predicted marriage go back to 1867. In that year the great Scottish physicist James Clerk Maxwell proposed a thought experiment that was later called ‘Maxwell’s Demon’. Maxwell’s Demon was purportedly a way to defy the second law of thermodynamics that had been proposed a few years earlier. The second law of thermodynamics is one of the fundamental laws governing everything in the universe, from the birth of stars to the birth of babies. It basically states that left to itself, an isolated system will tend to go from a state of order to one of disorder. A good example is how a bottle of perfume wafts throughout a room with time. This order and disorder was quantified by a quantity called entropy. Read more »