But once again I must stress that the Shannon-Weaver model is the mathematics of communications and does not address the value of the message at all. So under Shannon-Weaver it doesn’t matter that prions are only proteins, that mycoplasmas have no cell walls, that viroids are RNA without a protein coat. They fit within the communication model. The model addresses source, message, encoder, channel, decoder, receiver and noise. Noise can result in a miscommunication of an intended message and therefore, a malfunction (or perhaps improvement) in the molecular machine.
The bottom line to Shannon-Weaver is information, the reduction of uncertainty of the receiver in going from a before state to an after state. It is all about communications and all of these “lifeforms” are part of the communications (or miscommunications) in molecular machines.
If we were to proceed down the path of questioning whether the lowly virus, prion and viroid are “alive” – then we would be appealing to definitions of life which make “cuts” based on biochemical boundaries. Such cuts open the door for other types of arguments such as the following:
There are those who see an unbroken continuum between living and nonliving matter. If this is so, the question of life's origin becomes a moot point. Viruses, prions, mycoplasmas, rickettsiae and chlamidiae are offered as examples of organisms that bridge the chasm between living and nonliving. But the differences between living and nonliving matter are in fact so great that this chasm cannot be spanned.
Although viruses and prions are made from biopolymers, they are no more alive than the enzyme additives in some detergents. Viruses are lifeless complexes of proteins and nucleic acids. The biological activity of viruses, including their replication, is completely dependent on the metabolic activity of the infected cell. Prions are unique proteins that alter the structure of certain other proteins. The newly changed proteins in turn acquire prion-type activity, creating a domino effect of protein alteration. This property of prions renders them infectious. For reproduction, prions, like viruses, are wholly dependent on live cells.
Rickettsiae, chlamidiae and mycoplasmas, on the other hand, are among the smallest known living organisms, and are very much alive. The fact that chlamidiae and rickettsiae are obligate intracellular parasites only means that they have serious metabolic deficiencies. A clear distinction between living entities and nonliving substances is essential for a consideration of whether it is possible to go from one state to the other. For this reason we need to descend into the submicroscopic world of matter.
The elemental compositions of living and nonliving matter differ greatly.4 The actual chemical determination of living matter is done on "once-living matter". Before chemists can analyze living matter, they have to take it apart to isolate its individual components, thereby killing it. Thus the actual phenomenon of "life" is not amenable to detailed chemical scrutiny. In the very process of laying hold of isolated "purified" components of living matter, "life" slips out between the chemists' fingers, and what remains is an inert, "lifeless" substance. This is so because living cells are composed of lifeless, nonliving components. The implication is that the difference between life and death is a question of how biomatter is organized. Therefore, it should be possible to reverse the killing of cells by restoring them to their pre-disruption state. Why this has not yet been done in the laboratory will be discussed in the next chapter.
… In presenting a case for a tight logical link between analyzing the molecular aspects of life and the creationist paradigm, it is not enough to enumerate the components of living matter. Simply knowing the components of living matter is not enough to account for its biological activity.
Living matter behaves differently than its isolated components. Living cells incorporate selected substances and utilize them either for energy or as building blocks for growth. They also secrete metabolic waste. Living cells grow and divide into daughter cells. Lastly, when cells recognize unfavorable environmental conditions, they make metabolic adjustments to preserve their existence.1 Living matter gives every indication that it "wants" to stay alive. This is a property of the complex network of components in living matter. The whole seems to be more than the sum of its parts.
If we collect all of the ingredients from live cells, lace them in a membrane-enclosed vesicle, we have an inert, "lifeless" assembly of biomatter. This bag may be stored indefinitely in an environment hospitable for life, without the actual emergence of life. If we periodically analyzed the contents of this artificial "cell", we would find little change in its chemical composition. Such an arrangement of matter is called equilibrium.2
If we sampled the composition of life cells growing in a defined laboratory setting, surprisingly, the results would be similar, that is, we would find the chemical composition of live cells quite constant. But instead of the term "equilibrium", we say that matter in live cells is in a "steady state system". The significant difference between the two is the dynamic flux of matter through live cells.
A mechanical illustration of this difference is shown in Figure 3.1. Here, the contents of both vessels remain unchanged over time, but there is constant movement of liquid through vessel A. The flow of molecules through cells is an essential feature of life. (In contrast, the liquid in container B is stagnant.) The movement of water through a compartment, representing the flux of matter through the cell, is an oversimplification of what actually occurs. In reality matter changes as it travels through the cell. The incoming precursors (biomonomers) are simple substances which are gradually built up to successively more complex structures.
However, I do not believe that approach is adequate because it does indeed toss prions, viroids and viruses into the non-living bucket whereas they are the channel (or noise) for mutation (or miscommunications) in living systems.
IOW, excluding them from the model for "what is life v non-life/death" also puts the mechanism for evolution off the table – which evidently is the intent of the above article.
Shannon-Weaver, OTOH, does not disturb even the classic model of evolution which I personally find out-of-date, nor does it disturb any of the newer von Neumann based models, nor does it speak yeah or nay to abiogenesis, nor does it preclude either Intelligent Design or Young Earth Creationist. It is ideologically and theologically neutral on top of being elegant.
However, if the consensus here is to go with a biochemical definition - then I'm "game" for trying to nail the characteristics.
If some version of a quantum computer comes into existence and is in essence, pure mind, will it be a living organism? And is that what some humans already are? There is a great gap in human intelligences, yet we consider all biological humans as "living", though in reality some live short brutish lives, and others, such as Hawking, rise above biological constraints and live in a world of thought that perhaps most humans, let alone beasts, could never contemplate even if educated. Would a thinking quantum computer be superior to mankind? If a qc is conceivable, then why is the concept of God, as pure mind, inconceivable?