Ceci n'est pas un chat

I found this exhibit on my way through Chemistry this afternoon; this was the accompanying explanation:

In 1943 Erwin Schrödinger, whose "wave mechanics" laid the first foundations of what we now know as quantum mechanics, gave a series of public lectures at Trinity College, Dublin.  These were published a year later in a remarkable little book called "What is Life?  The Physical aspects of the Living Cell".  In it, Schrödinger perceptively argues, on the basis of physical laws and statistical mechanics, and long before the discovery of the structure and DNA by Crick and Watson, that the genetic code must be written in the isomeric structure of a large molecule of what he called "a periodic solid" by which he meant essentially a long chain polymer, i.e. DNA!  It's a tour de force of the power of logic and physics.


Towards the end of the book Schrödinger begins to ponder about what the venerable subject of thermodynamics can tell us about living systems.  In a chapter entitled "Order, Disorder and Entropy" he points out that all living things seem to confound the natural tendency of things to go over into disorder.  In other words that living matter evades the decay to equilibrium.  However, just because a system can maintain itself far from equilibrium for a very long time does not mean that it is necessarily "alive".  Schrödinger gives the following example:


"...If a glass filed with pure water and a second one filled with sugared water are placed together in a hermetically closed case at constant temperature, it appears at first that nothing happens, and the impression of complete equilibrium is created.  But after a day or two it is noticed that the pure water, owing to its higher vapour pressure, slowly evaporates and condenses on the solution.  The latter overflows.  Only after the pure water has totally evaporated has the sugar reached its aim of being equally distributed among all the liquid water available.  These ultimate slow approaches to equilibrium could never be mistaken for life..."


In "cei n'est pas un chat" Indian ink replaces sugar.

I will find a reson to walk this way over the next week or so and see what the levels of water are doing.

My language skills are abysmal and unlike the majority of people in the UK I did not study french at school, but I can scrape together enough to understand the title.  I had a conference-enabled holiday in Belgium once and we visited the home of Magritte; the most excellent guide happily switched languages to keep all visitors informed, a skill which always has my admiration.