Howard Pattee is retired Professor Emeritus at SUNY, Binghamton, in the Department of Systems Science and Industrial Engineering Pattee was cited at the 1967 International Union of Biological Sciences Symposia on Theoretical Biology as offering one of two pre-life systems with potential for variability and heredity (for Pattee, tactic copolymers). The other was A. G. Cairns-Smith's replication, with variations, of macromolecules on clays. See C. H. Waddington's report in Nature. Pattee criticized the symposium attendees for claiming that biology was simply "physics and chemistry" without citing a single law of physics.Normal | Teacher | Scholar
Although the chemical bond was first recognized and discussed at great length in classical terms, most physicists regarded the nature of the chemical bond as a profound mystery until Heitler and London qualitatively derived the exchange interaction and showed that this quantum mechanical behavior accounted for the observed properties of valency and stability. On the other hand, it is not uncommon to find molecular biologists using a classical description of DNA replication and coding to justify the statement that living cells obey the laws of physics without ever once putting down a law of physics or showing quantitatively how these laws are obeyed by these processes.When someone pointed out the necessity of segregating the prograrnme and the rnachinery of the computer, which corresponds in biological terms to the separation of genome and phenotype, the conference organizer, C. H, Waddington, reported that Pattee said,
the logic of this necessity has been discussed by von Neumann in Theory of Self Reproducing Automata (University of Illinois Press, 1966). Pattee put the same point in another way when he emphasized that an effective hereditary system requires both a memory store, which must be constructed of rather inactive materials if it is to be stable enough and a mechanism not only for being replicated but also for affecting its surroundings. Whether it is theoretically possible to conceive of a substance which is sufficiently unreactive to be an efficient store and also sufficiently reactive to affect the environment is perhaps debatable. In practice, however, it is clear that living things on this Earth have not discovered such a material. They have in general settled on the rather unreactive DNA as the memory store and on RNA and proteins to decode this into enzymes which participate both in the replication of the store and in interactions with the environment. Following this line of thought, Pattee raised a question from the point of view of quantum mechanics, which seemed perhaps rather recondite to many of the biologists present. The stability of the algorithms stored in DNA is ensured by quantum mechanical processes which define the configuration of single DNA molecules. Their replication and decoding depend on the actions of enzymes, such as the polymerases, which ensure that the bases in a single strand of DNA are paired up correctly with the complementary bases to form the second strand or the corresponding RNA. The existence of such enzymes cannot, he claims, be deduced from the fundamental laws of physics. They are acting as "non-holonomic" constraints to limit the degrees of freedom of the whole system. Their origin at some very early stage of evolution is one of the major problems. Moreover, the stability of the algorithms stored in DNA is ensured by quantum mechanical processes, but the polymerases decode this into quantities of proteins and other cell constituents sufficiently large to operate according to the laws of classical physics. We are confronted therefore With an example of a "quantum measurement", a matter which seems to cause theoretical physicists many headaches.In later years, Pattee rarely cited the importance of quantum physics, which is the critical element for the creation of new information. In 1969, Pattee asked the basic question about the connection between matter and symbols that he was to pursue the rest of his life:
How do we tell when there is communication in living systems? Most workers in the field probably do not worry too much about defining the idea of communication since so many concrete, experimental questions about developmental control do not depend on what communication means. But I am interested in the origin of life, and I am convinced that the problem of the origin of life cannot even be formulated without a better understanding of how molecules can function symbolically, that is, as records, codes, and signals. Or as I imply in my title, to understand origins, we need to know how a molecule becomes a message. More specifically, as a physicist, I want to know how to distinguish communication between molecules from the normal physical interactions or forces between molecules which we believe account for all their motions. Furthermore, I need to make this distinction at the simplest possible level, since it does not answer the origin question to look at highly evolved organisms in which communication processes are reasonably clear and distinct. Therefore I need to know how messages originated.During symposia on theoretical biology in the late 1960's, Pattee used John von Neumann's theory of self-reproducing automata to argue for the causal power of symbols over the biological world. Von Neumann had distinguished the abstract "description" (the coded symbols carrying the structural information of the self-replicating machine) from the actual material "construction" of the automaton. Pattee identified von Neumann's "description" with the linear sequence of genetic code in the genotype. He identified von Neumann's "construction" with the building of the three-dimensional phenotype. There are two different things going on in biology, the abstract information coded in the "software" and the concrete material information structure or "hardware." Pattee saw the symbolic description as in charge of the physical instantiation and said that "life is matter controlled by symbols," making the connection to a biosemiotic description of life.
ConstraintsAs a physicist, Pattee assumes that deterministic physical laws govern all dynamics, which can in principle be computed given the initial conditions and the boundary conditions. Pattee, and many of today's biosemioticians, e.g., Terrence Deacon, prefer to call the initial and boundary conditions "constraints." Pattee says that his concept of constraint is not easily understood. This has led to considerable confusion when applied to biosemiotics, whose practitioners know little about dynamics and their readers even less. Pattee describes the upper level in a hierarchical system as producing constraints on the dynamical motions of the lower levels. Thus, Roger Sperry's "downward causation " of the molecules in a rolling wheel constrains their motions to those of the wheel's motion. Pattee is aware that some physical situations cannot be described dynamically, particularly those involving a large number of particles, but must be described statistically. He thinks that the microscopic collisions of material particles are time-reversible and describable dynamically. He defines his important term "constraint" and explains the need for two different "descriptions" in hierarchical systems,
The common language concept of a constraint is a forcible limitation of freedom. This general idea often applies also in mechanics, but as we emphasized in the beginning, control constraints must also create freedom in some sense...fundamental forces do indeed "limit the freedom" of the particles ... the fact is that they leave the particles no freedom at all. The physicist's idea of constraint is not a microscopic concept. The forces of constraint to a physicist are unavoidably associated with a new hierarchical level of description...forces of constraint are not the detailed forces of individual particles, but forces from collections of particles or in some cases from single units averaged over time. In any case, some form of statistical averaging process has replaced the microscopic details. In physics, then, in order to describe a constraint, one must relinquish dynamical description of detail. A constraint requires an alternative description. Now I do not mean to sound as if this is all clearly understood.
Origin of Life and the Problem of Measurement in Quantum MechanicsFor a 1969 colloquium of scientists hoping to get "beyond" the problems in quantum theory, Pattee wrote the very provocative article, "Can Life Explain Quantum Mechanics." In it, he argued that,
The physical meaning of a recording process in single molecules cannot be analysed without encountering the measurement problem in quantum mechanics, nor can the symbolic aspects of the genetic description be understood without an interpretation of the matter-symbol relation at an elementary physical level. Living matter behaves differently from non-living matter.In 1996, Pattee wrote about the difference between dynamical controls, thought to follow deterministic, time-reversible physical laws, and his symbolic or semiotic controls, which emerge in a higher level of a hierarchical system:
measurement problem. The problem is how to decide when a measurement is completed, that is, how to determine when and how the dynamics of physical laws is mapped into the semiotic record of a measurement There has always been an apparent paradox between the concept of universal physical laws and semiotic controls. Physical laws describe the dynamics of inexorable events, or as Wigner expresses it, physical explanations give us the impression that events ". . . could not be otherwise." By contrast, the concepts of information and control give us the impression that events could be otherwise, and the well-known Shannon measure of information is just the logarithm of the number of other ways... The modern attempts in physics to live with this paradox require introducing statistical concepts that allow alternatives into the framework of physical laws by reinterpreting the essential distinction between the laws themselves that describe all possible alternatives and the initial conditions that determine one particular case. Statistical physics accepts the inexorability of the laws, but assumes that virtual alternatives can exist in the microscopic initial conditions. One measure of the alternatives is the entropy. Thus, we create imaginary statistical ensembles of systems which all follow the same dynamical laws, but that have different sets of initial conditions. These virtual microscopic states are restricted only by statistical postulates and their consistency with macroscopic state variables. A modification of this classical view by Born, points out that initial conditions of even one particle can never be measured with formal precision, and therefore even the classical laws of motion can predict only probability distributions for trajectories. Only when a new measurement is made can this distribution be altered. The fact remains, however, that all our formal semiotic descriptions and computations, whether we interpret them as probabilistic, statistical, or fuzzy, are in practice assumed to be manipulated by crisp, strictly deterministic rules, even though physical laws require the execution of semiotic rules to be stochastic events. This issue of where dynamical description should be replaced by symbolic description is not simply an empirical problem but a problem of definition and of epistemology. To objectify the question as far as possible, we must ask not what we mean by information but what the information itself means in the physical world. In physics, where there is not yet any consensus on how to properly describe the measurement process, it is at least generally agreed that a measurement must have been completed when there exists a semiotic record of the result, even though exactly what constitutes a semiotic record is not clear. The point is that the function of measurement cannot be achieved by a fundamental dynamical description of the measuring device, even though such a law-based description may be completely detailed and entirely correct. In other words, we can say correctly that a measuring device exists as nothing but a physical system, but to function as a measuring device it requires an observer's simplified description that is not derivable from the physical description. The observer must in effect choose what aspects of the physical system to ignore and invent those aspects that must be heeded. This selection process is a decision of the observer or organism and cannot be derived from the laws. Just as the observer's cognitive selection process is necessary for a measurement, so natural selection is necessary to generate function or meaning in the genetic DNA. The concept of selection, natural, cognitive, or any other form, implies a choice of alternatives. The alternatives may be considered real, virtual, or states of a memory, but in any case, as with measurement, the language of fundamental physical laws is at a loss to predict what alternative is selected or even describe the process of selection which, by definition, must occur outside the system being described. The brain is full of knowledge that may appear unrelated to any immediate useful action, construction, or control. Nevertheless, this high level of information is what forms our models, our value systems, our aesthetics, and our world view from which we ultimately derive our goals, decisions, and actions. It is certainly not meaningless. This problem of delayed meaning arises because of the apparent total lack of intrinsic connection between the time and place where we acquire new information and the time and place where it is selected or when we decide to use it in our actions and efforts to control. In physical jargon this arbitrariness in time scale or lack of any definable temporal relation between events is called incoherence. In linguistics jargon it is called displacement. It is this temporal arbitrariness that is one reason semiotic control is difficult to incorporate into physical models or any dynamic formalism where time or sequence defines the next-state transition.In 2000, Pattee emphasized the time reversible nature of all dynamical processes the theory of semiotic controls and how they are related to natural dynamical laws is a foundational issue and the cause of apparently undecidable controversies. In physics a fundamental theoretical issue is called the
Causation is gratuitous in modern physicsThe Newtonian paradigm of state-determined rate laws derived from a scalar time variable and explicit forces only strengthens the naive concept of one-dimensional, focal causation. Reductionists take the microscopic physical laws as the ultimate source of order... The fundamental problem is that the microscopic equations of physics are time symmetric and therefore conceptually reversible. Consequently the irreversible concept of causation is not formally supportable by microphysical laws, and if it is used at all it is a purely subjective linguistic interpretation of the laws. Hertz (1894) argued that even the concept of force was unnecessary. This does not mean that the concepts of cause and force should be eliminated, because we cannot escape the use of natural language even in our use of formal models. We still interpret some variables in the rate-of-change laws as forces, but formally these dynamical equations define only an invertible mapping on a state space. Because of this time symmetry, systems described by such reversible dynamics cannot formally (syntactically) generate intrinsically irreversible properties such as measurement, records, memories, controls, or causes. Furthermore, as Bridgman (1964) pointed out, "The mathematical concept of time appears to be particularly remote from the time of experience." Consequently, no concept of causation, especially downward causation, can have much fundamental explanatory value at the level of microscopic physical laws.At a 2015 workshop at UC Berkeley, From Information to Semiosis, Pattee described his idea of "symbol-based self-replication," based on John von Neumann's logic,which requires a clear distinction between descriptions and constructions, where descriptions are time-independent and construction vary in time. He describes a "cut" that is a distinction between the self and the non-self.
A description requires a symbol system or a language. Functionally, description and construction correspond to the biologists’ distinction between the genotype and phenotype. My biosemiotic view is that self-replication is also the origin of semiosis. I have made the case over many years (e.g., Pattee, 1969,1982, 2001, 2015) that self-replication provides the threshold level of complication where the clear existence of a self or a subject gives functional concepts such as symbol, interpreter, autonomous agent, memory, control, teleology, and intentionality empirically decidable meanings. The conceptual problem for physics is that none of these concepts enter into physical theories of inanimate nature Self-replication requires an epistemic cut between self and non-self, and between subject and object. Self-replication requires a distinction between the self that is replicated and the non-self that is not replicated. The self is an individual subject that lives in an environment that is often called objective, but which is more accurately viewed biosemiotically as the subject’s Umwelt or world image. This epistemic cut is also required by the semiotic distinction between the interpreter and what is interpreted, like a sign or a symbol. In physics this is the distinction between the result of a measurement – a symbol – and what is being measured – a material object. I call this the symbol-matter problem, but this is just a narrower case of the classic 2500-year-old epistemic problem of what our world image actually tells us about what we call the real world.Pattee connects his "epistemic cut" with the Heisenberg - von Neumann "Schnitt" somewhere between the measurement apparatus and the observer's mind. This led to the faulty idea that wave functions would not collapse without conscious observers. John Bell asked whether the observer needs a Ph.D. and where this "shifty split"is located. Bell made a drawing of the "shifty split," which we annotate with the moment that a measurement becomes possible, the moment when irreversible information is created. As Pattee noted years ago, this is the moment when a semiotic record is created.
ReferencesHow does a molecule become a message? Can life explain quantum mechanics? Physical Problems of Decision-Making Constraints/a> Pattee's Papers on Academia.edu