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Randy Isaac
 on October 14, 2010

What is Information?

The word “information” is used in many different ways, often leading to confusion. It may be helpful to consider three of the categories in which the term is often used.


This post is adapted from Randy Issac’s scholarly article that examines the possibility of detecting God’s existence through science.

The word “information” is used in many different ways, often leading to confusion. It may be helpful to consider three of the categories in which the term is often used.

  1. Complexity. Information theorists quantify information as the logarithm of the number of possible states of a system. Four coins, for example, can have 16 different possible combinations of heads and tails. The amount of information is the log of 16, or 4 bits. This category includes so-called Shannon information, named after Claude Shannon who in 1948 published a seminal analysis of the amount of information that can be transmitted in a noisy communication channel. This type of information is related to entropy, which also depends on the number of possible physical states.Changing some heads to tails can generate an informational pattern without changing the amount of information. Just as there is no conservation principle that limits changes in entropy there is no conservation principle that limits changes in information. In closed systems as well as in open systems with energy flow, information can increase. Rolf Landauer has shown that while energy is not necessarily dissipated in the change or in the increase in information, it is necessarily dissipated in the destruction of information. In other words, there is no fundamental constraint on increases or changes in complex information.
  2. Compressibility. Another use of the term information refers to the minimum amount of information required to describe a particular state of the system. It is easier to describe the state of all coins being heads than it is to describe coins in a random sequence. Both states have the same amount of information in terms of complexity, but regarding compressibility, the repetitive sequence has less information. This category includes Kolmogorov information and information that can be expressed in simpler algorithms. It is extremely useful in the telecommunication industry in transmitting audio and video data.This type of information can change significantly without any change in complexity whenever the state of the system changes. For example, if some coins are heads instead of tails, the compressibility of the information changes while the total complexity remains the same. Any discussion of the “generation” or “creation” of information is ambiguous without further clarification since it can refer either to increasing the amount of information or to changing the state of the system.
  3. Significance. The popular use of the term information most often refers to the significance attributed to a particular physical state of a system. This significance can either be a physical characteristic or, more commonly, an abstract or symbolic relationship. The physical shape of the letter “A” conveys significance in the English language that is not mandated by the physical characteristics of that letter. It could have had a different meaning. Intelligence is sometimes defined as the ability to carry out symbolic reasoning. Therefore, meaningful information in this category requires intelligence to generate the abstract significance.Note that physical complexity must exist in order for meaning to be attributed to it. Paul Revere’s famous phrase “…one if by land and two if by sea…” is an example of far-reaching information being conveyed by two bits of information. If the lanterns did not exist, the information would not be conveyed. If an intelligent agent had not assigned that meaning, the lanterns by themselves could not transmit the desired effect. DNA and computer code information: same or different?

Stephen Meyer’s use of the term “specificity” puts it in this third category of information. Meyer adds a second type of specificity, namely functionality. Usually functionality refers to the characteristics or action of a design compared with the design specification set by the designer. If that functionality involves symbolic meaning at any level, then an intelligent agent does need to be involved in some direct or indirect way. What Meyer overlooked, however, is that if no symbolic meaning is involved, then physical processes might be adequate to determine functionality. For instance, computers are constructed from a set of binary systems in which one state in each binary is assigned the symbolic meaning of “0” or “1”. No attribute of the binary system determines which meaning must be assigned to which state. An intelligent agent capable of symbolic reasoning must be involved. However, in living systems the ability to reproduce is a type of complex functionality that has a physical, but not a symbolic, function. If a living cell reproduces, it functions—otherwise it dies. There is no necessity for an intelligent agent to be involved at any level. Significance of information cannot be quantified and is not conserved in any quantitative way.

The information argument sounds appealing at the surface. Most of our daily use of information involves computers, language, and numbers, which are all laden with symbolic value. It makes sense to us that information requires intelligence. The remarkable similarity between DNA code and binary information code makes it tempting to attribute the same requirement of intelligence to the generation of DNA information. Closer analysis, however, shows that every biomolecule in a living cell can be assessed by its value to survival as opposed to any symbolic relationship set by an intelligent designer. DNA information is complexity with significance endowed by the physical and chemical functions that enable its host organism to sustain existence. This means that natural selection is a viable process for determining DNA information. An intelligent agent is not necessarily required.

The case for an intelligent designer as laid out by the ID community is not compelling for the scientific community. Science has not answered the question of God even in the less stringent form of an indeterminate intelligent agent.

Note: The opinions expressed in this article are those of the author and not of the American Scientific Affiliation.

About the author


Randy Isaac

Randy Isaac is a solid-state physics research scientist and executive director of the American Scientific Affiliation (ASA), where he has been a member since 1976 and a fellow since 1996. Isaac received his bachelor’s degree from Wheaton College in Illinois and his doctorate in physics from the University of Illinois at Urbana-Champaign. He joined IBM to work at the Thomas J. Watson Research Center in 1977 and most recently served as the vice-president of systems technology and science for the company.