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 »

The greatest artist

by Ashutosh Jogalekar

A dinosaur fossil found in China with a clearly visible feathered exterior (Cosmos Magazine)

Neil Shubin’s “Some Assembly Required” is a delightful book whose thesis can be summarized in one word – “repurposing”. As Steve Jobs once put it, “Good artists create. Great artists steal”. By that reckoning Nature is undoubtedly the most magnificent thief and the greatest artist of all time. Repurposing in the history of life will undoubtedly become one of the great paradigms of science, and its discovery has not only provided immense insights into evolutionary biology but also promises to make key contributions to our understanding and treatment of human disease.

Among many other achievements of Darwin’s great theory was the explanation and prediction that similar parts of organisms had similar functions even if they might have looked different. One of the truly remarkable features of “On the Origin of Species” is how Darwin gets almost everything right, how even throwaway lines attest to a level of understanding of life that was solidified only decades after this death. The idea of repurposing came about in the “Origin” partly as a reply to objections raised by  a man named St. George Jackson Mivart. Mivart was in the curious position of being a man of the cloth who had first wholeheartedly embraced Darwin’s theory and studied with Thomas Henry Huxley, Darwin’s most ardent champion, before then rejecting it and mounting an attack on it, timidly at first and then vociferously. Mivart’s own tract on the subject, “On the Genesis of Species” made his not-so-subtle dig at Darwin’s book clear.

Darwin’s response to Mivart’s objections in the “Origin of Species” (from the author’s collection; 1882 edition)

Mivart’s basic objection was similar to that raised then and later by creationists. Darwin’s theory crucially relied on transitional forms that enabled major leaps in life’s history; from fish to amphibian for instance or from arboreal life to terrestrial life. But in Mivart’s view, any such major transition would involve not just a sudden change in one crucial body part, say from gills to lungs, but a change in multiple body parts. Clearly the transition from water to land for instance involved hundreds if not thousands of changes in organs and structures for locomotion, feeding and breathing. But how could all these changes arise out of thin air? How could gills for instance suddenly turn into lungs in the first lucky fish that crawled out of water and learnt how to survive on land? This problem according to Mivart was insurmountable and a fatal flaw in Darwin’s theory. Darwin took Mivart’s objections seriously enough to include a substantial section addressing them in the sixth and definitive edition of his book, first published in 1872. In it he acknowledged Mivart’s problems with his theory, and then did away with them succinctly: There is no problem imagining organs being used in different species, Darwin said, as long as they are “accompanied by a change in function.” In writing this Darwin was even further ahead of his time than he imagined. Read more »