In a previous post we looked at Christoph Adami’s book The Evolution of Biological Information, and in particular its problematic definition of information. Today we will move beyond the definition to his first argument intended to motivate the claim that evolution increases biological information. For this, he draws an analogy between natural selection and Maxwell’s demon.
Maxwell’s demon is a hypothetical entity that can increase the energy in a compartment by choosing to admit or exclude incoming particles based on their speed. By excluding slow particles and admitting fast ones, the demon can increase the compartment’s energy. Natural selection, according to Adami, works in a similar way, accepting mutations that increase information while excluding those that decrease it.
The “Increase of Information Law”
While Adami admits that there are exceptions in which evolution allows the loss of information, he says that this analogy “strongly suggests” that evolution will lead to an increase of information over time. It leads, he suggests, to an “increase of information law.”
Evolution, however, does not operate like Maxwell’s demon. That is for three reasons. First, natural selection is not perfectly effective. Rather, natural selection only means that fitter organisms are more likely to survive. In many cases, the effect of mutation will be so small that the difference will be inconsequential. Further work, such as that by William F. Basener in “The fundamental theorem of natural selection with mutations,” shows that under plausible assumptions the evolutionary process will be unable to maintain information in the genome against the tendency of incoming mutations.
Loss and Damage
Second, evolution frequently proceeds by loss and damage. This is elucidated in Behe’s book Darwin Devolves. In many cases, natural selection favors something that degrades or disables functionality thus decreasing rather than increasing information. In my own work, I saw this happening in a computer model of evolution, described in “Tierra: The Character of Adaptation.” When evolution proceeds by loss, the information in the genome is actively jettisoned by natural selection.
Thirdly, in many cases information is not identifiable by itself. This is the fundamental problem highlighted by irreducible complexity and the waiting-times problem. It is a highly contrived and implausible scenario in which every mutation can be tested by itself. Rather, multiple mutations would have to be tested in combination. Even that would be insufficient as complex molecular structures that work with other structures cannot be tested independently. Natural selection will be simply unable to identify whether a structure is information bearing or not.
As such, evolution does not work as an analogy to Maxwell’s demon. First, natural selection is not perfectly effective. Second, natural selection often favors changes that actively destroy information. Thirdly, information is rarely evaluable as independent mutations. For all of these reasons, evolution fails to be an analogy to Maxwell’s demon. The analogy does not support Adami’s claim that evolution will increase information, nor does it underwrite a law of increasing information.