A Thermodynamic attempt at exploring the meaning of life -Hanoon Razak

Second law of thermodynamics states that the entropy of an isolated system (such as the universe) only increases. Entropy is the degree of randomness or disorder in a system. This essentially means that the disorder in the universe is always going to increase.?

To understand the maximisation of entropy intuitively, let's take an example. Imagine some hot tea in a thermo-flask (isolated system) at 90 degree centigrade. Even though the tea in its entirety exists at 90 degrees, its molecules may comprise of higher and lower temperatures which when added up averages to a 90 degree in total. The molecules which are in constant motion also transfer energy with each other through collisions. All of these adds up to the total energy of the tea and its corresponding temperature.?

There are astronomical number of configurations in which the energy can be distributed among the molecules such that the average property of the tea (90 degrees) remains the same. Each of these possible configurations are called microstates. The property of the entire system (the tea at 90 degrees) is called the macro-state of the tea. Hence the macro-state 'tea at 90 degrees' could have an innumerable number of possible microstates.?

Given this case, it shouldn't be entirely impossible for the tea to exist in a configuration such that the bottom half of the tea exists in colder state and the top half at a warmer state while maintaining the tea in its entirety at 90 degree centigrade. Yet this does not happen.?

Although, the tea to exist at 90 degrees could have astronomical numbers of possible configurations (microstates) of energy distributions among molecules, by imagining a scenario where the molecules are divided into an ordered hot and cold region, we are restricting the number of microstates it can possibly exist in.?

A class of 40 students (20 boys and 20 girls) can have seating arrangements in 40! (3.04 x 10??) different Ways. But if we were to separate the boys from girls on each side they could only arrange themselves in 20! ×20!×2= 1.18 ×103? ways , effectively reducing the total number of arrangements the class of 40 students can arrange themselves in.

A system will always exist or tend to exist in such a way that the number of microstates (configurations or arrangements) it can possibly exist in (without changing the macro-state) is maximised.?

Hence entropy is simply the measure or number of microstates a macro system can possibly exist in. And the system in its equilibrium always exists in a state where its entropy is maximised.?

Now let's pour the tea into a cup and leave it on the table. The energy is concentrated inside the walls of the cup and is hence highly ordered and less spread. Since it is out of the thermo-flask, it is no longer an isolated system. The energy in the tea slowly spreads to the surroundings (thereby increasing the entropy of the entire system that includes the cup of tea and the surrounding atmosphere) until the temperature in the tea and the atmosphere is similar. The energy is now least concentrated, most spread/ disordered and hence has the most entropy.?

Even though there exists enough energy in the atmosphere to raise the temperature of the tea back to 90 degree centigrade, this doesn't happen due to the sole reason that entropy never decreases. For any work to be done, we require an energy gradient. There needs to be a region of higher energy and a region of lower energy. This means that even immense amount of energy that is fully spread out in the universe cannot do any useful work. In our case, the heat is only useful to us when it is in the cup of tea and not spread into the atmosphere.?

The quality of energy in terms of the work it can do reduces with increase in entropy/randomness/spread. Analogously, any useful work we do is simply contributing towards increasing the entropy of the universe.?

We have established two things here, one that the universe is diligently and incessantly working against any sort of order or complexity until it turns itself into a boring uniform noise of nothingness. Secondly, doing any work using an energy gradient is only going to decrease the gradient and increase the randomness/entropy. Which non-coincidentally is just what the universe wants.?

Naturally a question arises. If entropy never decreases and if universe is against order and complexity, how did earth evolve highly structured, highly complex and ordered self-replicating cells and eventually organisms of increasing sophistication and complexity capable enough to question the very nature of existence??

For life on earth, shouldn’t the path towards maximum disorder, randomness or entropy be breaking down of systems and organisms to elemental particles and dissolving into soil ?

Before we explore the answer to the question, we will need to understand how the universe achieves its disorder. For illustrative purposes, lets imagine a freshly burnt matchstick. One can observe the gradual change of the steady stream of ordered laminar flow of smoke arising from the matchstick into a disordered and turbulent mess. Yet by zooming into this turbulent mess of a flow, one can observe that the turbulence is achieved through thin multiple streams of ordered laminar flow going in random directions.?

Therefore, it is evident that the universe achieves its entropy maximization through localized ordered systems of low entropy.?

The earth, unlike the tea in the thermo-flask is not an isolated system. It is being constantly bombarded with immense amount of energy primarily from the sun. This energy is being sequestered by plants thus marking the beginning of the food chain.?

For an organism, life can simply be defined as a struggle against entropy. A struggle to keep the life wielding organism away from disorder. The work done by the organism and its supporting life systems to keep itself alive in turn reduces the energy gradient and increases the overall entropy of the universe.

Hence on a larger scale, life is simply the localised system of low entropy that the universe employs in order to achieve its ultimate goal of maximum disorder.?

And the point of life is to create enough order and complexity to serve the larger disorder.