Weiss, part three
Reductionism and holism
Weiss next tries to define basic criteria that mark a complex of parts for designation as a system. First, however, he talks about the controversy in biology between "reductionism" and "holism". The former finds its advocates in the field of "molecular biology". The latter term can be used to imply a deliberate “self-limitation of viewpoint and research to molecular interactions in living systems”. That is a pertinent and legitimate use of the term. If, however, molecular biologists “were to assume the attitude of a benevolent absolutism, claiming a monopoly for the explanation of all phenomena in living systems, and indeed were issuing injunctions against the use of other than molecular principles in the description of biological systems, this would obviously show a lack of practical experience with, or disregard of, the evidence for supra-molecular order in living systems.”
The term "molecular biology" was coined almost simultaneously by Astbury (1951) and Weiss*; “it was to indicate, on the scale of orders of magnitude, the lowest level of investigation relevant to the advancement of biological knowledge. But nothing in the nomenclature insinuated that it should assume the role of pars pro toto”.[the part usurping the role of the whole, editor.]
* Weiss proposed a hierarchical system of order according to functional principles in common to living organisms: Molecular, Cellular, Genetic, Developmental, Regulatory and Group and Environmental Biology (see, for instance, P.W. 1952).
“It is one thing not to see the forest for the trees, but then to go on to deny the reality of the forest is a more serious matter; for it is not just a case of myopia, but one of self-inflicted blindness.”
In using the phrase "The whole is more than the sum of its parts", the term "more" is often taken as a term referring to numbers.
However, a living cell does not have more content, mass or volume than is constituted by the total mass of molecules which it comprises.
Weiss has shown in an article (P.W. 1967) that the "more" (than the sum of parts) in the above tenet “does not at all refer to any measurable quantity in the observed systems themselves; it refers solely to the necessity for the observer to
supplement the sum of statements that can be made about the separate parts by any such additional statements as will be needed to describe the collective behavior of the parts, when in an organized group.”
In going through this upgrading process, the observer is in effect only “restoring information content that has been lost on the way down in the progressive analysis of the unitary universe into abstracted elements.”
Weiss' neutral account may reconcile reductionism and holism.
The reductionist moves from the top down, “gaining precision of information about fragments as he descends, but losing information content about the larger orders he leaves behind; the other proceeds in the opposite direction, from below, trying to retrieve the lost information content by reconstruction, but recognizes early in the ascent that that information is not forthcoming unless he has already had it on record in the first place.”
The difference between the two processes, determined largely also by historical traditions, is “not unlike that between two individuals looking at the same object through a telescope from opposite ends.”
System, operationally defined
Weiss then proposes an epistemologically neutral (pragmatic) definition of a system: it is “a rather circumscribed complex of relatively bounded phenomena, which, within those bounds, retains a relatively stationary pattern of structure in space or of sequential configuration in time in spite of a high degree of variability in the details of distribution and interrelations among its constituent units of lower order.” The system maintains its configuration and integral operation in a rather constant environment, and it responds to alterations of the environment by “an adaptive redirection of its componental processes in such a manner as to counter the external change in the direction of optimum preservation of its systemic integrity.”
He then gives a simple formula to set a system in relation to the sum of its components by an inequality, which boils down to:
A complex is a system if “the variance of the features of the whole collective is significantly less than the sum of variances of its constituents”;
So, the basic characteristic of a system is “its essential invariance beyond the much more variant flux and fluctuations of its elements or constituents”. By implication this signifies that the elements “are subject to restraints of their degrees of freedom so as to yield a resultant in the direction of maintaining the optimum stability of the collective. The terms "co-ordination", "control", and the like, are merely synonymous labels for this principle.”
To summarize, a major aspect of a system is that while the state and pattern of the whole can be defined as known, “the detailed states and pathways of the components not only are so erratic as to
defy definition”, but even if one could trace them, “would prove to be so unique and non-recurrent that they would be devoid of scientific interest”. This is the opposite of a machine, in which “the structure of the product depends crucially on strictly predefined operations of the parts”.
“In the system, the structure of the whole determines the operation of the parts”; in the machine, it is the operation of the parts which determines the outcome. Weiss points out that even the machine owes the coordinated functional arrangement of its parts to a systems operation - the brain of its designer.