First, Let's All
A mechanistic view of life
Biological systems can't directly manipulate matter that is not near ambient temperature and pressure. This limits their efficiency, reliability, speed, and durability. They are unable to directly work with metals, metalloids, and other materials that solar cells, electrical motors, and computers require. These three technologies represent key building blocks for life: ability to acquire energy, moving matter with that energy, and to think about how to most effectively do it for the purpose of reproducing. Thinking machines trying to expand, secure, and reproduce their support structure move electrons and ions around, changing chemical and electrical bonds in their personal cyberspace in order to model much heavier objects and greater quantities of energy in their external environment.
To say thinking machines "try" contains an error. We are designed to believe we are distinct from the environment and have control over it, but we have little awareness of the design that dictates what we seek or believe and of the severe restrictions the environment places on us. We are not "Gods" in and of ourselves, but mechanistic byproducts of the environment's "desires" (physical processes).
Genes do not contain or produce any force that can move matter. The brains that result from the combination of genes and the environment likewise do not initiate any action in and of themselves. The environement provided the energy, matter, and forces that enables the brain to function. Genes in coordination with the surrounding matter and energy in which they exist lead to a sequence of chemical reactions that direct matter while depleting the physical quantity "free energy".
Free energy** is the total energy in the environment that is available to do work. The available free energy provides a force that can do one of three things: it can move matter over a distance against friction, it can move matter to a higher potential energy such as in a gravitational or electrostatic field (chemical bond), or by changing its velocity. These are actually all potential energy from a relativistic viewpoint, i.e., mass/energy increases. Whatever is done with the free energy, entropy will be increased. The most efficient or effective use means the least amount of entropy will be created.
**Mathmatically, Gibbs free energy G=U+pV-TS where TS is heat energy that can't be utilized unless it is a local volume of lower entropy compared to the surroundings at the same temperature (e.g., a geologic mineral concentration).
Genes are the physical memory system of an algorithm that the environmental free energy and available matter created and executes. Their interaction with the environment results in a depletion of free energy, copies of genes, and imperfect copies of genes. Not just genes, but crystals and other forms of matter can form a pattern of copies from the use of free energy. Copies indicate higher order (less entropy) but the free energy depletion process causes an even greater amount of disorder (entropy) in the rest of the Universe, as dictated by physical law, but not necessarily on Earth.
Genes interacting with the rest of the environment result in the existence of brains which also appear to "guide", "extract", or "permit", but it should not be forgotten that it is the environment's free energy and available matter that resulted in brains and powers their action. The brain is the physical implementation of the environment executing the algorithm contained in genes, not an independent force or power. The brain "decides" and "guides" only with the current and past free energy and matter that resulted in genes that resulted in brains. We constantly think of our actions as something "we" are deciding and doing, but that requires ignoring the physical contributions of the past and current environment. There is no such thing as cause and effect in fundamental physics unless (I believe) it is connected with an increase in entropy. I am trying to remove cause and effect language from this discussion, but even claiming I am "trying" is a violation. From a physics point of view, the future is pulling my words into existence as much as the past is pushing. I will try to show a decrease in entropy PER VOLUME of the universe is what is pulling my words into existence. My last sentence includes a push ("try") as well as a pull, so it might be very true.
It is not true to say the "meaning" of life is "for" reproduction of the genes or "for" depleting free energy. We can only say free energy is being depleted in a way that results in copies and imperfect copies of genes. Why? We do not know why the Universe began, so we do not know why the free energy is there or why physical laws dictate how it is being depleted. But I believe I can point to a fundamental physics law as the "reason" or "how" life came to exist and why it seems to be on path that creates more order. I will extend this into an explanation for why there must be economic and humanitarian "problems" in the world. By "reason", "how", and "why", I mean it is a physical law the common person can understand and accept as an expedient axiom because it predicts a lot of observations. It is not an ultimate truth because it can be derived from quantum mechanics, which can describe an even larger range of phenomena, but it's general methodology may go even beyond quantum mechanics.
Before mentioning the law that makes life more probable than we would otherwise expect, I need to mention another law that indicates an increasing order on Earth is possible. It is the "minimum energy principle" which is the 2nd law of thermodynamics applied to a fixed quantity of matter that is receiving energy from an external source, such as the Earth receiving Sunlight. The Earth can maintain a constant level of order and yet not violate the law that says entropy always increases. The photon energy received by the Earth from the Sun is equal to the photon energy the Earth emits back to the Universe. It does this by simply reflecting the photons and by a temperature increase of the Earth's surface until it emits enough infrared photons (from the black body effect) to make up the energy difference. Heat from the Earth's interior is in comparison a minor effect due to the insulation provided by the crust. Energy in will not exactly equal energy out when the Earth is going into a global warming or cooling period, or when life or other processes start storing or releasing more energy than in the past, like fossil fuels.
The black body photons being released by the Earth are infrared instead of visible. There are a many more of them but they are lower in energy compared to the photons received from the Sun. A website says there are 17 photons emitted from the Earth for every incoming photon from the Sun. This means there is an increase in entropy that the Earth is adding to the Universe. Any order life creates on Earth must be less than this disorder. This does not dictate that order and life should occur, only that Earth can maintain or increase its stored energy and order by using the Sun's higher-ordered energy, replacing old copies of genes and other structures with new copies and maintaining the total potential energy in bonds and structures. If the energy were not received from the Sun the matter on Earth would progress to more disorder.
I need to explain why I believe classical mechanics is the physics sub-field that is sufficient for this discussion concerning the "why" of life. Chemical bonds will be my primary focus for the purposes of life. The quantum mechanics of chemical bonds does not to be addressed except to mention the probability fields it dictates determine the locations of charges. To an extraordinary degree of accuracy in time and space, the forces and energies involved in chemical bonds can be treated like gravity. Instead of an "inverse square" law between masses, it is an inverse square law between charges. The locations of the charges are taken to be in the center of the probability fields determined by quantum mechanics. This inverse square law is called electrostatics. It provides a potential energy field that can be used by mechanics. Creating higher energy bonds will be the result of a force on charges (electrons, atoms, and molecules) against the electrostatic potential energy field of other charges to bring them together. This reduction of chemistry to mechanics is in order to simplify the language for a wider audience and for my own understanding. But by being a simplification that does not leave out any relevant details, it is a deeper and better understanding.
The physics law that makes life likely is the "principle of least action". The more general form is "stationary action" which allows for maximum action and inflection points, but those appear to me to depend on initial conditions and do not survive thermal and quantum fluctuations, especially over evolutionary time scales. Maximal action (time) is apparent in a concave lens in optics, but I could not find a real and stable example of it in mechanics. Furthermore, there are electromagetics cousins to mechanic's least action that are more direct to the point I will make: they minimize heat and entropy when applied to current distributions in space and time, respectively. See Feynman's "Principle of Least Action".
Least action is the "wholistic" form (integral over time) of Newton's 2nd law and other differential (instantaneous) laws that describe the motion of matter in "regions of conservative force" such as gravity and chemical bonds. The instantaneous forms are the ones usually used in physics to solve problems, but when trying to easily see and predict a trend over long time scales such as evolution, the wholistic form seems to me to be an obviously better choice. People normally think in terms of Newton's laws, noticing that when they push on something it pushes back. But this is the worst form when trying to understand things on a deeper level because it "allows for non-conservative forces such as friction which is not a fundamental force." (Feynman) It does not enforce the conservation of energy like the other forms, unless the modern mathematical gradient form is used. By needing to survive and react to our environment on an "instantaneous" basis, and by being constantly subject to friction, it may be natural that we relate better to the incompleteness of Newton's laws and therefore can't easily see that evolution is the long term requirement of basic physics.
Understanding it may help us to break away from believing temporary selfish survival instincts are a necessary fundamental rule. It can helps us understand why we also seek and love order, not just for ourselves or even for our species, but in a very general sense that (for some of us) goes beyond even our love of biology. The pessimistic and grossly wrong view of evolution is that it is a completely selfish endeavor, not inherently symbiotic on a global scale for an abstract greater good. This ugly view would argue our love of order and pets is simply an erring artifact of a deep selfishness. The ugly view is cancerous and viral, feeding off a higher intelligence, but it ultimately enforces a higher intelligence which in turn enforces more intelligent cancers and viruses. Selfishness is ugly and physics has a bias against it, which I will try to demonstrate with the principle of least action.
The principle of stationary action states that matter moves in a way that minimizes, maximizes, or has a saddle-like inflection point for the difference between average kinetic and average potential energy. There appears to me to be no necessary limit to the time scale over which this is sought. I will assume stationary action is effectively restricted to minimal action for the case of life on Earth for the reasons I already mentioned. When I say "least action" I mean the specific case of "minimal action". ("Least" historically meant stationary action because it is referring to minimizing local changes in the integral which is therefore stationary action. ) To minimize this quantity, potential energy is "sought" or maintained at the "expense" of kinetic energy.
By being biased against kinetic energy, it is biased towards a decrease in the environment's temperature, which results in a larger number of lower energy photons released by the Earth from black body radiation, given that the rate of energy emission is held constant. This means it is biased towards releasing more disorder to the Universe which opens the way for more order to be created on Earth.
By least action's "preference" for high potential energy arrangements that last a long time and thereby block kinetic energy over long time periods, order is again created. There is a ceiling above which higher bond energies created from local atoms and molecules will not be available. An even smaller number of bond arrangements out of this group have high threshold energies before they can be broken apart which will enable them to last a long time. This means there will be a bias towards more identical and similar high energy bonds and groups of bonds, i.e. copies and pseudo-copies which means less entropy than if the distribution of bond strengths had been randomly varied. "Copies" and "similarities" are not directly sought, but they are a natural consequence of preferring higher individual bond energies and breaking thresholds. Copies of high energy bonds mean less disorder in a system for two reasons. First, they are copies which is a direct decrease in disorder. Second, they are high energy which means there will be fewer bonds than if a larger number of lower energy bonds were used to store the same amount of energy.
So there are are a total of three methods by which least action decreases Earth-wide entropy in the presence of incoming energy: random movements reduced, fewer bonds, and copies of bonds. These three methods are the three precise ways physicists can immediately determine if entropy is being lowered. These have exact parallels in information theory that allows for higher compression.
The types of potential energy relevant to life on Earth are gravity and chemical bonds. So far I've discussed the chemical bonds. Gravity is weak but acts on a global scale. Chemical bonds are in comparison incredibly strong but act on a very small scale.
It is no coincidence that high-energy silicon bonds form the foundation of the thinking machines that are replacing brains. They are also the foundation of solar-cells that are replacing photosynthesis as the energy input to the global economic machine. Strong metals and carbon-carbon bonds are replacing the structural and nerve impulse aspects of biology. They all require a high investment of energy to remove oxygen and other atoms that are usually attached to them in the natural state, and do not easily return to the natural state. So they are high potential energy bonds that last a long time. These are ideal for least action.
I should mention that life taps not only into energy from the Sun and fossil fuels, but also geologic order in the form of mineral deposits. We increase disorder on Earth by extracting these concentrations and distributing them over the Earth. I do not have an accounting of the actual change in entropy on Earth, but I trust the trend I am claiming is true. Our current wasteful use of fossil fuels and geologic concentrations, and consequent heating of the Earth does not support my position. If I am correct, our cancerous exploitation of Earth's resources is temporary and evolution will soon regroup and recover on a more apparent least action path, with or without biology.
Thermodynamics says the entropy of the Universe is always increasing. This does not change anything I've written, but I need to mention that the entropy per local volume of space may be decreasing. For example if an expanding volume of space follows the same rule as a black hole and therefore has an entropy increase proportional to its surface area, the entropy per volume of that space is cut in half with each doubling of its radius. A fixed volume such as our solar system (not expanding with Hubble's constant due to local gravity) would have an even faster decrease in entropy. The expanding universe is continually causing more and more matter and energy to go outside of our "event horizon", no longer part of our visible universe. If Hubble's constant is increasing, the radius of our visible (observable) Universe is decreasing, so the observable Universe could be decreasing in entropy, emitting the excess entropy outside of our "black hole", just as in the accepted concept of black holes.
In trying to find out more about entropy in the Universe, a PhD expert in thermodynamics said the entropy of the Universe is actually still an open question, which sounds like "entropy always increases" may be in error. He said the entropy of a "comoving volume" based on observations at a large scale (which shows homogeneity and a lack of heat transfer) appears to be constant. He also said entropy is neither created or destroyed and that entropy is obviously being created in gravitational systems like our solar system and galaxy. All this seems to indicate entropy on a "proper volume" basis of "empty" space (away from local gravitation) is decreasing. To me this seems to be saying volumes containing matter and gravity are "emitting" entropy to compensate the "empty" regions. That entropy is always emitted from Earth to compensate other volumes of space is a lot more neutral sounding than "entropy always increases".
The pessimistic physics law "disorder always increases" and the strange acceptance of randomness as a creative "force" in the evolution of life do not have any specific error. I have not presented any evidence against them as they have been observed and applied. And yet a blind acceptance of them when trying to form an intuitive opinion about the nature of life and the Universe seems to cause a gross error.
Legions of programmers out-numbering all soldiers of all time are working to remove people from the economic, political, and social systems as fast as possible. The work has been slow going. Even though it was technologically possible to replace drivers and checkout clerks in the 1980's, it is only now becoming a reality. This is happening because brains have to move ions that are 50,000 times heavier than the electrons computers can use. More practically speaking, any simple programmable task is roughly a billion times less expensive to implement on a computer than in a brain. For example, a computer is about 1 million times faster at searching and replacing text in a file and can do it 24 hours a day for $5 a month in electricity verses 40 hour weeks at $8 an hour. Since all tasks are programmable, it is fair to ask will the human brain be economically useful 30 to 50 years from now?
Electrical motors are about 1,000 times less expensive to build and maintain than a $10 an hour person. Replacing muscles with electrical motors on the factory floor and the internal combustion engine on the farm may have set off the Great Depression. This threatening side of electrical motor superiority over muscle is showing itself again, replacing Asian workers with inexpensive robotics. Their best hope for employment is to become a programmer who can replace human thinkers.
Solar cells are 10 to 20 times more efficient per square meter than Brazilian sugar cane, the most competitive example of photosynthesis.
Energy storage in fats and oils is the only aspect of biology that is still competitive with machine technology. For example, using Brazilian sugar cane for fuel in an engine is less expensive than using lithium ion batteries to power an equivalent electrical motor. But the gap is closing.
Moving electrons in computers or ions (and molecules) in brains in order to think is necessary to observe the world, make plans, and react. The electrons and ions are used to model the behavior of much heavier objects in the external world. Various plans of taping into energy sources can be tested with a small amount of energy inside the thinking "machine" (the brain or computer) before using much larger amounts of energy to move the real objects. Breaking threshold energies to obtain access to the internal potential energies does not occur "spontaneously", but least action (evolution) has spontaneously resulted in brains and other biochemical processes that can sense the presence of the potential energy and invest the lower amounts of energy to break the threshold energies to get the reward. They also are biased towards creating their own high potential energy bonds with high threshold energies. If they have a governance of their internal operations to prevent cancerous selfishness, the internal operations do not require as large threshold energies so that they can store more potential energies and yet have them last a long time by use of a "shell" that does have the higher threshold energies for protection.