The nature of the earliest forms of life on our planet are unknown and may remain that way, but we keep coming closer to understanding what they may have been like. Whatever they were like, it seems clear that they arose out of a process of molecular self-assembly. This process is commonplace in our universe. If you look up into the night sky, you’ll see countless stars and galaxies which arose spontaneously by a process of self-assembly.
Out of the featureless initial state of the universe they developed into the wondrous complexity we find today. There is no “vital force,” no galaxy-power which make them what they are — why imagine that such a thing is responsible for us? In 1953, Harold Urey and Stanley Miller set up an experiment to reproduce early chemical conditions of the Earth and added “lightning” to jump-start the process of forming amino acids, the building blocks of life. They achieved some success, but there were problems. The strongest objections, perhaps, is that amino acids aren’t all that difficult to produce — so what they achieved is perhaps not so remarkable.
Creationists like to argue that life couldn't have naturally developed from non-life because of entropy. Essentially, they claim that order and complexity, the reduction of entropy, cannot occur naturally — but this argument simply doesn’t work.
First, the Second Law of Thermodynamics, which limits the ability of a natural system to have a decrease of entropy, only applies to closed systems. When a system is open and can exchange energy with the outside, then that open system can have a decrease in entropy and an increase in order. The most obvious example of this is, coincidentally, a living organism. All organisms run the risk of approaching maximum entropy, or death. But they manage to avoid this by drawing in energy from the world: eating, drinking, and assimilating.
Second, whenever a system experiences a decrease in entropy, a wider price must be paid. When a biological organism absorbs energy and grows — thus increasing in complexity — work is done. When work is done, it is not done with 100% efficiency. Some energy is always wasted and some given off as heat — this means that in the larger context, overall entropy is increased even as entropy decreases locally within an organism. Thus, the Second Law is not violated.
We can see how organization can arise out of entropy by looking at the example of gas clouds — and the key to it all is gravity. If we examine a small amount of gas in an enclosed space and at uniform temperature, we find that it does absolutely nothing. The system is at its state of maximum entropy and we’d have no reason to expect anything to happen.
But if the mass of the gas cloud is large enough, then gravity will begin to play a significant role. Over time, pockets will start to contract, exerting even higher gravitational forces on the rest of the mass. The clumping centers will contract further, beginning to heat up and give off radiation, thus allowing for temperature gradients to form and heat convection to take place.
Thus, a system which was supposed to exist in thermodynamic equilibrium and maximum entropy has moved on its own to a system with less entropy, but more organization and activity. Clearly, gravity changes the “rules” of a system in important ways, allowing for events which might seem to be excluded by thermodynamics.
The problem is that appearances can deceive, and the system described above must not have been in true thermodynamic equilibrium. Although a uniform gas cloud should stay as it is, it still seems to “go the wrong way” in terms of organization and complexity. Life works the same way, appearing to “go the wrong way” with complexity increasing and entropy decreasing. In reality, though, it’s all part of a very long and complicated process whereby entropy is eventually increased, even if it appears to decrease locally for (relatively) brief periods.
