Thursday, January 26, 2017

Put it to rest once and for all: Thermodynamics versus Evolution

One of the common apologetic arguments against the theory of evolution is the one where theists would claim that the "Laws of Thermodynamics" prove that the theory of evolution is impossible (their favorite is "The 2nd Law of Thermodynamics").

The short and dirty answer is:
If one makes that argument, that means that either they don't understand Thermodynamics, or don't understand Evolution, or don't understand both.

(and yes, dear theist, that includes the charismatic pastors and preachers - from whom you've probably heard that argument in the first place - who put on a facade of looking like someone who knows what they're talking about)

But such a short answer doesn't really serve much to move the discussion forward.
After all, we're here to cure ignorance, not laugh at it, right?

As part of my degree in Machine Engineering, I completed a course in Thermodynamics on July 2016.
So now I can finally prepare an article explaining what is Thermodynamics anyway, and why it doesn't contradict the theory of evolution (and actually knowing what I'm talking about).

(Disclaimer: Please note that for the sake of this explanation I will be mentioning the existence of mathematical equations, but I will not be providing them, since I think it would only add to confusion, and is not really necessary for the purpose of this discussion)

What is Thermodynamics

Thermodynamics is essentially a scientific field that provides mathematical equations for calculating the... wait for it... dynamics of heat (i.e. "Thermo").
In other words: How heat moves from one object to another, how it physically affects it, and how the whole process affects energy.
The main equations of Thermodynamics involve the following parameters:
Temperature, Pressure, and Volume.
When any of these parameters is changed, it directly affects the other parameters, based on the structure of the object in question.

For example: Let's say that we have a cylindrical piston as our object of choice.
This piston is inside a hollow cylinder, and it can move up or down.
Inside the hollow cylinder we have some sort of gas (let's say it's regular air).
Different types of gas have different properties which change the way it's affected by the thermodynamic equations (mostly having to do with the rate of change).
Let's also say that this air inside the cylinder has a certain temperature, we'll call it "T".
This air also has a certain pressure, we'll call that "P".
And obviously, the cylinder has a certain volume, which we'll call "V".

Next, we see what happens when we change either of the 3 parameters and how it affects the other parameters:
  • Heating or cooling the air inside the cylinder will change the temperature (T).
  • Moving the piston up or down will change the volume of the air inside the cylinder (V).
  • Injecting or extracting additional air into/from inside the cylinder will change the pressure (P).
If we heat the air inside the cylinder, based on the equations of Thermodynamics, this will cause an increase in pressure and volume. But if the piston is stationary (i.e. the volume is constant), then the increase in pressure will be more pronounced.
Similarly, moving the piston to decrease the volume of the air will increase the temperature and pressure. And injecting additional air into the cylinder will increase temperature and volume (thus moving the piston).

Also, each such a change in the 3 parameters will elicit a change in the energy of the system. Specifically, it will cause the conversion of one type of energy into another type of energy (for example, the thermal energy used for heating the system will be converted into kinetic energy which will move the piston when the air volume increases). There are, of course, mathematical equations that describe these changes in energy, based on those parameters.

The above are basically the essentials of Thermodynamics.
Example for an "Isobaric Process" where the Pressure (P) of the system is "locked"
but as the Temperature (T) is increased, so is the Volume (V).

But how do the Laws of Thermodynamics fit into this scenario?

1. First Law of Thermodynamics: "Energy cannot be created or destroyed. It can only be converted from one form to another."

What this means is that the energy required to cause a change in the system cannot come from nowhere, and it can't disappear into nothingness. It has to be introduced either from an external source outside the system (i.e. a flame to heat the air, or an engine physically moving the piston), or it must be converted from one form to another inside the system (i.e. the kinetic energy which moves the piston is converted into thermal energy when the air is compressed and heated).
In other words: The total sum of energy in the system must remain constant.
Energy can come in many forms:
Thermal (heat), Kinetic (movement), Elastic (stored inside a deformed spring), Chemical (fuel of some kind), Electrical (electric charge), and so on.

2. Second Law of Thermodynamics: "The total Entropy of an isolated system always increases over time."

"Entropy" is a very confusing concept to understand. It's most commonly described as "the degree of disorder within a system". But that is a very confusing description which doesn't accurately describe what it really is.

A better description of Entropy, would be this:
"The total number of statistical possibilities for energy to be distributed within a system."
So, to tie that in with the 2nd law of Thermodynamics:
If a system is isolated from outside influence, as time goes by, the energy within the system will be more and more spread out, and it will be harder and harder to statistically predict where different forms of energy will be "clumped" together (i.e. the number of statistical possibilities of energy distribution will increase).

For example:
If you take a bowl of room-temperature water and let it sit for a while motionless on a table, you will be able to statistically predict with high confidence that every section within the bowl will have the same temperature. At this point in time, the bowl's Entropy is 0 (zero).
But if you take a few drops of hot water, and you spill it in the middle of the bowl, you will be able to statistically predict with high confidence that the specific section where the hot water was poured, will be with a higher temperature than the rest of the bowl. In other words: The hot water is relatively "clumped" in the middle of the bowl. However, as time goes by, the hot water will spread out more and more, and you will be less able to statistically predict which sections of the bowl will have low or high temperatures. At this point in time, the bowl's Entropy is >0 (higher than zero).
Eventually, the bowl will have a uniform temperature again which was slightly higher than it was in the beginning (due to the hot water). At this point in time, the bowl's Entropy will be 0 again (zero).
The 2nd Law in action: Note how the heat is "spread out" with time.

In this scenario, based on the 2nd Law of Thermodynamics:
A certain section of the bowl will NOT spontaneously start heating up or cooling down relative to the rest of the bowl...
UNLESS there is some sort of outside influence (for example, another drop of hot water, or maybe a cold body touching the bowl) - in which case it would mean that THE SYSTEM IS OPEN AND NOT CLOSED.

Here is an interesting video that I found to be very useful in explaining entropy and the 2nd law:


Why do we even need the 2nd Law of Thermodynamics?

I know what you're probably thinking: "Well, duh, Eitan! Everyone knows those things instinctively! OBVIOUSLY the 2nd Law is true! But then why do we need this law anyway?? Isn't it rather useless?"

Well, no. It's not a useless law at all.
In fact, it's one of the most important laws invented in the field of engineering.
The reason we need this law is that it is what helps engineers design better and more efficient machinery, and more importantly: It helps engineers design machines that actually work.
Without this law, what we have is a set of mathematical equations (involving Temperature, Pressure and Volume, remember?) which engineers use to calculate the way their machines would work, including how energy is utilized and produced by them.
HOWEVER, engineers MAKE MISTAKES! And sometimes, an engineer would design a machine which should work superbly on paper, but when they build it in practice all of a sudden something goes wrong and the machine doesn't function the way it should.
The reason could be that the design of the machine BROKE THE 2ND LAW OF THERMODYNAMICS due to some error that the engineer made somewhere. In other words: The engineer designed an IMPOSSIBLE MACHINE, and that's why it didn't work.

This is why we need the Laws of Thermodynamics: They're used as a verification mechanism for engineers to prevent them from making mistakes when designing machines.
It's a MATHEMATICAL law. A CONSTRAINT used for the prevention of errors.

But what about the "closed system" part? Based on what you said, isn't everything an open system??

That's a good question.
And once again this terminology can be rather confusing, especially for people who have no experience in machine engineering.

A "closed system" is not necessarily a physically "isolated" system.
What it is, is a system which is not thermodynamically influenced by outside sources.

For example, an engineer could design a machine that really is "closed" because it's encased within some sort of an insulator that prevents it from being heated up or cooled down from outside. This method of designing "closed systems" is something that's extremely common in machine engineering. There are tons of different parts of machinery that for various reasons need to be insulated from the rest of the machinery: Car parts, complex computer electronics, space-grade machinery, avionics and more. Even your refrigerator at home has sections within its machinery that have to be insulated in order for it to work properly.

Also, sometimes engineers would design a machine which is not "truly" a closed system. But it's open to some degree to outside influence such as heat and radiation, and yet during design they would consider their systems to be thermodynamically isolated. Often times the engineers consider these machines to be "good enough" for their intended purpose, before they break down and you need to buy a new one.

So what does it have to do with Evolution?

That's an even better question!
And the answer is:

Abso-fucking-lutely NOTHING.
The 2nd law of Thermodynamics has absolutely NOTHING to do with Evolution.
Nothing. Nada. Zero. Ziltch.

Why? Because, as everyone keeps telling them theists: The Earth as a whole is NOT a "closed system"! The Earth receives almost endless amounts of energy from the sun:

It receives heat which provides thermal energy to wherever is currently daylight, which prevents from the Earth as a whole to reach higher entropy (remember what entropy means? the "spreading out" of energy. In this case, I'm talking about the sun's heat dissipating and the Earth cooling down until everyone and everything is frozen to death).

The Earth also receives light (solar) energy which is absorbed by photosynthesizing plants, which in turn convert CO2 into Oxygen, and provide food for all the herbivores on Earth. And then those herbivores, in turn, provide food for the predators on Earth... And the circle of life goes round and round, ever propelling evolution forward.
If it wasn't for the sun's light, almost all living beings on Earth would die out.
Except maybe those that managed to evolve into utilizing the Earth's thermal or chemical energy instead (underwater volcanic vents, for example).

"Thermo-Dynamics" = Dynamics of Heat
Gee, I wonder what is a big source of heat that's affecting earth...
How about that big ass ball of fire in the sky?

Conclusion

I hope that you managed to keep your attention span for as long as needed to understand what I explained.
I hope that you now realize just how dumb theist apologists sound when they use the "2nd law of Thermodynamics" argument to try and argue against evolution.

If there's anything that you feel needs clarification, then feel free to ask in the comments below.

Stay curious.

Addendum

After learning the above, some theists would feel inclined to mention the Big Bang theory and the "creation" of the universe as something that supposedly breaks the laws of Thermodynamics (i.e. it appears to break both the 1st and 2nd laws in how energy seems to have been "created out of nothing", and entropy seems to have been "reversed" almost infinitely).
I can assure you that the Big Bang theory does NOT, in fact, break the laws of Thermodynamics either. But that's a matter for a whole topic of its own, which inadvertently has to touch on "harder sciences" such as Cosmology and Quantum Mechanics.
I'll let astrophysicist Sean Carroll answer this question: