Fri | Feb 21, 2020

Letter of the Day | Entropy or evolution

Published:Monday | January 27, 2020 | 12:18 AM

THE EDITOR, Madam:

Dear Mr. Espeut, in your article ‘Entropy or evolution’ that appeared in The Gleaner on January 24, 2020, the statement of the Second Law of Thermodynamics should have been “the entropy in an isolated system is increasing”. The law does not hold for the universe because of the clumping effects of gravity. However, in my view, the correct statement reinforces the gist of your article on the analogies of the Second Law of Thermodynamics with the social sciences.

My reference for these comments is the Wikipedia article on the Second Law of Thermodynamics in https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#Entropy.

A physical example is helpful in demonstrating the points. I get a plastic container and fill it part way with ice cubes and then with water, so that the ice is on the bottom and the water is on the top, though it fills the spaces between the ice cubes. Call this configuration A. I place the plastic container in an insulated box so that it is an isolated system. When I check after a while, all the ice would have melted, and there would be only water. Call this configuration B, or thermodynamic equilibrium. The Second Law of Thermodynamics tells us that

1. configuration A cannot remain indefinitely;

2. configuration A will change to configuration B; and

3. configuration B cannot change back to configuration (impossible).

But the Second Law of Thermodynamics only applies to isolated systems. Its effects can be mitigated by some appropriate interaction (such as work) with the outside. There is a loop hole in opening up the system.

So, suppose I wanted the plastic container to remain in configuration A for as long as possible. I could cool at the bottom and heat at the top. It would not work to heat at the bottom and cool at the top. I would need to do some careful investigation before settling on and fine-tuning an approach. Diligence is also required in conducting the operation.

This demonstrates an important lesson for efficient and effective management in Jamaica, that it is imperative to select a viable policy after careful study and to apply that policy effectively with discipline.

One final point. One should distinguish between what is possible from what is impossible, between what is reasonable from what is unreasonable. One should not attempt to convert configuration B back to configuration A without removing the water entirely from the plastic container and starting all over.

Clement McCalla

clemmccalla@gmail.com