Cost of information processing

Cost of information processing

Ideas occur at a blink of eye. People might think ideas are costless. But brain is the most expensive organ metabolically. At two percent of body weight, brain consumes twenty percent of total energy.

Similarly, information transmission may cost little in modern environment. But the building and maintenance of information and communication structures cost not thousands, not millions, not billions, but trillions of dollars. Information processing is extremely costly.

Information, from the technical point of view, is the reduction of entropy. From the entropy law, the reduction of entropy is always resource intensive.

We are going to discuss some aspects of information generation and preservation in living systems. These may highlight the universality of the cost of information processing in life, which we also belong to.

Information can be preserved by RNA. But with the exception of some viruses, genetic codes of most living systems are preserved by DNA, which is more expensive to make than RNA. Why does life choose more expensive material to preserve genetic information? This is because DNA is chemically more stable than RNA. DNA can preserve information better than RNA. RNA is costly to make. DNA is even more costly to make. Preserving information is costly. For living systems more complex than viruses, their genetic codes can only be preserved by DNA.

There are four types of RNA nucleobases, G, A, C, U. There are also four types of DNA nucleobases, G, A, C, T. Three are common for RNA and DNA. But the fourth type U, is replaced by more complex, and more costly T. Why does life take an extra trouble and cost to make another nucleobase? This is because C (Cytosine) may degenerate into U (Uracil), making errors in information transmission. Some errors are acceptable in RNA works for lower cost. But errors in DNA need to be small as DNA codes pass from generation to generation. More complex and hence more distinguishable T (Thymine) is used in DNA codes. Information transmission is always costly. For long term information transmission, more costly ways that are less prone to error are adopted.

When DNA chains are formed, each DNA molecule is attached to the chain at the sugar base from 5’ to 3’, from the fifth carbon to the third carbon direction. The required specific direction causes many complexities in DNA replication. Why life insists on this uni-directional formation? This is because the formation of DNA requires energy. TP, (TP as in ATP, the main source of energy in life), the energy source of the incoming molecule is attached to 5’ carbon in the sugar. The formation has to accommodate the location of the energy source. The actual mechanism is more complex. But the essence is the need for energy in the formation of DNA, the information carrier.

From the perspective of physics, information is the reduction of entropy. The reduction of entropy requires resource input. From the perspective of life, formation, preservation, and transmission of information all require resources. Human beings are part of the physical and biological world. Information processing in human society must be inherently costly.

In standard economic theory, information is costless. Then economists assume the market is “imperfect”. This “imperfectness” makes information costly.

Some might say. In the end, information is costly in both theories. There is no difference.

But there are many differences. In standard theory, a more “perfect” society is a better society. At the same time, patent laws are promoted. They would make information more costly and hence make the society less “perfect”. There are many such logic inconsistencies in the standard theory. Why is such a theory adopted? The ruling class adopt such a theory because it gives the flexibility to justify any policy that benefit themselves.

The information theory based on physics and biology, on the other hand, gives an accurate description of information processing and social interactions. Its mathematical structure parallels many results in the entropy theory of information and statistical mechanics. More information about the theory can be found at Chapter Five: The Entropy Theory of Mind in the book The Unity of Science and Economics, 2015.