Argument from the second law of thermodynamics
Creationists often claim that the Second Law of Thermodynamics (sometimes abbreviated 2LoT) precludes evolution (and/or the Big Bang). Often this is explained by saying that the second law says that everything tends toward disorder; since living beings (or the universe) is highly ordered, they could not have formed spontaneously. Along with this idea, they may argue that it seems if organisms were to form by chance within the universe, the ever increasing entropy would wipe out these organisms before they ever had a chance to become as intricate and detailed as they are today.
From Thermodynamics vs. Evolutionism at trueorigin.org:
- "The second law presents an insurmountable problem to the concept of a natural, mechanistic process: (1) by which the physical universe could have formed spontaneously from nothing, and (2) by which biological life could have arisen and diversified (also spontaneously) from a non-living, inanimate world. (Both postulates form essential planks in the platform of evolutionary theory in general.)"
A.C. McIntosh, Information And Entropy – Top-down Or Bottom-up Development In Living Systems?, International Journal of Design & Nature and Ecodynamics, Vol. 4, Issue 4:
- "Consequently, the fundamental laws of thermodynamics show that entropy reduction which can occur naturally in non-isolated systems is not a sufficient argument to explain the origin of either biological machinery or genetic information that is inextricably intertwined with it."
Entropy is not the same as disorder
The most common definition of the second law is: "The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium." The second law of thermodynamics uses the word entropy, which is what causes the confusion (Or allows the lies, depending on how you look at it.) The meaning of the word entropy that is used in the second law is: "For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work." Using that correct definition the second law of thermodynamics obviously has nothing whatsoever to do with evolution. It never did, it's just about thermal energy. (As should be evident by its very name.) But the definition that the apologists use is: "A measure of the disorder or randomness in a closed system." And using that definition, the second law of thermodynamics would mean: The random disorderliness of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium. However, this is not only an incorrect use of the second law. It is also untrue, some closed systems will tend to fall into disorder, while some will become more orderly. Examples: Disorderly dust clouds in space eventualy gravitate towards a central/denser point, forming a star. If we presume that humanity is orderly, and that the apologists definition of entropy is valid, we should observe the continuous destruction of humanity - human populations should dwindle, human technology should decline. That this is not occurring is not evidence that the definition is incorrect - it would mean that the Earth is not a closed system. Evolution is compatible even with the apologists definition - the earth itself is not a closed system. In a universe consisting solely of the earth and the sun, biological evolution is still possible - the total "randomness" will increase consistently as the sun releases energy, but on earth, that energy is temporarily ordered.
The Big Bang theory does not claim anything about prior events
That is, Big Bang theory does not currently tell us what happened before the Big Bang, or whether there even was a "before the Big Bang", in the sense of a point in space-time which unambiguously predates the Big Bang itself. Without knowing how much entropy, if any, was present in the pre-Bang universe, you cannot claim that the Big Bang contradicts the second law.
The Earth is not a closed system
The second law of thermodynamics describes what happens to closed systems, that is, systems in which mass and energy are confined to the system and cannot enter or leave. However, the Earth is not a closed system, since it receives radiation from the Sun and also radiates heat and light into space. The Earth's crust is an even more open system, because heat and material is often ejected from the Earth's interior (through volcanoes and other methods). This provides a wealth of energy that drives "machines" such as climate patterns and the flourishing of life. If the Earth was a closed system, these processes might have "run down" and ended, but as long as the Sun continues to heat the planet they are in no danger of stopping.
The argument would apply equally well to known, normal reproduction within a species
If the earth could only become more disordered or more "worn down", it would not be possible for populations of life forms to grow and flourish. In fact, every time a cell copies or repairs its own DNA, it creates more information, at least in the obvious sense of producing a longer string of nucleotides. The second law of thermodynamics must allow the creation of ordered systems, or else it would not be possible for new, young, healthy organisms to be descended from older organisms.
In order to argue that the second law prevents evolution, one must demonstrate that even though known harmful and harmless mutations and normal reproduction occur, beneficial mutations could never occur. This seems to be a hopeless task, because there is no fundamental difference, either in physics or in the theory of evolution, between "harmful" and "beneficial" mutations, and because beneficial mutations have indeed been observed to occur.
Raised free energies can be the result of natural processes
The McIntosh quote above relates more to abiogenesis than to evolution (since evolution requires no processes that are physically different from normal reproduction plus mutation). McIntosh claims that the formation of the complex machinery necessary for life requires a positive free energy, and thus cannot happen spontaneously. This has been empirically disproven many times over, as many organic molecules have been produced through lifeless processes, and in fact are found in some comets and meteorites. McIntosh also makes claims about the unique nature of genetic information, claiming that it transcends the physical/chemical medium that it inhabits. However, he gives no clear way of deriving any of this from the second law itself, instead simply proposing it as something that would support his statements.
- Response to this argument at talkorigins.org
- Argument From the 2nd Law of Thermodynamics at strongatheism.net.