aCenter for the Philosophy of Nature and Science Studies, Niels Bohr Institute, Copenhagen, Denmark
Abstract. In this note some epistemological problems in general theories about living systems are considered; in particular, the question of hidden connections between different areas of experience, such as folk biology and scientific biology, and hidden connections between central concepts of theoretical biology, such as function, semiosis, closure and life.
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Introduction
The aim of this brief note is to consider partly hidden ideas about theoretical biology and its subject matter, living beings, organisms in their ecosystems -- which means beetles, cows, worms, bacteria cells, green algae, and dinosaurs, their history and interactions, their development and evolution, their structure and function, their origin, self-organization, the extinction of individuals as well as species, and the genesis of higher modes of life. In other words, an extremely multifaceted subject. First, however, recall an observation on the fate of general systems theory, which in the 1960s and 1970s had the ambitious goal of synthesizing the general fields of cybernetics, information theory, operation analysis, and specific fields, such as evolutionary theory and thermodynamics. That goal was not achieved and various reasons may be given for the failure, but an important factor might have been a too high level of theoretical generality in accounting for the highly different types of systems included in the ambitions of systems theory [1]. With this in mind, we could ask for the possibility of facing a similar situation with respect to the current trends in systems thinking.
Experiential, experimental, and theoretical biology
We commence with the epistemology of evolutionary systems theory (complex
adaptive systems, developmental systems, self-organizing systems, etc.). This
idea may be called the hidden prototype fallacy. It focuses on the risk of
becoming seduced by our own theoretical creations, blinded by the life of
abstractions, and it asks if we all commit a fallacy of presupposing certain
characteristics of the class of systems under investigation (e.g., evolutionary
systems), even though these are not accounted for by the theoretical apparatus
of our theory. The argumentative rhetoric found in many discussions within the
field of self-organizing systems theory (and others) tends to hide basic
connections between folk biology, theoretical biology (e.g., evolutionary
systems theory), and experimental biology in one of its disciplinary
normal-science forms. We tend to neglect the deep role played by real
biology as a reservoir of experience and knowledge about living systems. I
claim that we should more explicitly cultivate such connections between
experiential, scientific and theoretical biology; but also that we should be
critical about the limits of such connections when they are hidden to explicit
discourse. To explain this idea, I have to give some definitions and
interpretations.
Folk biology: Even though one should be careful about
scientism-related[*] connotations of this term
(especially if one associates it with the term `folk psychology' within
philosophy of mind, where it is occasionally supposed that in some distant
future of neuroscience, folk psychological terms can be reductively eliminated
when neoroscientific terms take their place), folk biology as used here
is simply a name for the phenomenological fact that before anyone may learn
scientific biology, we all experience the biology of real creatures, we see
animals move by themselves, we see flowers grow and unfold, and we may even
experience stories the adults tell about very small or invisible living beings
like bacteria, amoebae and algae; creatures that some of us eventually come to
see in school, or on television. The later fact should make it clear that the
phenomenological experiential folk biology in a modern society is deeply
influenced by the products of scientific instrumentation and science-derived
notions and ideas about microbial life, cells, genes, molecules and so on. Even
though the borders between folk biology and scientific biology are vague in
this sense, we do indeed have both kinds of systems of experience, with
the important historical asymmetry that the everyday life and language is
primary (ontogenetically and historically) to scientific biology.
Prototypes: Prototypes may not be the best notion to use in a
'scientific' context, because it describes a semantic feature of everyday
language that, in some concept-fields, there is an instance (the prototype)
that is more central in (seemingly) having most of the content-aspects of that
notion than other instances. Thus, an apple is a more prototypical instance of
the general everyday concept 'fruit' than, say, the nut in the fruiting body of
the grass-like sedge plant -- even though botanically, both a equal instances,
each with its own particular properties [2]. It is a characteristic
feature of most of the notions used within one of the frames of thought or
paradigms of theoretical biology (such as evolutionary systems, developmental
systems theory, biosemiotics) that they are rather abstract and vague.
Abstract in the sense that they denote very general properties of life,
and that they can be conceived of at some high or medium level of abstraction
from concrete instances; and vague because it is seldom that the
definitions of the notions in question entail clear-cut demarcation criteria to
decide whether specific instances belong to the system type (or posit the
property) in question. Here are some relevant examples of abstract and vague
notions (some of which are closely related, almost by family-resemblance, and
thus grouped together):
(a) self-organization (or emergence, autopoiesis, autocatalysis)
(b) evolution (or development)
(c) communication (or semiosis, information processing)
(d) living (or feeling, acting, learning)
To the extant that we, within a given paradigmatic frame, can use these terms
in a coherent way, we are also able to decide (within the limits of some
ambiguities) if a concrete specimen of life, or a physical concrete dynamic
system, instantiates one or more of these concepts. E.g., from my understanding
of the original theory of autopoiesis [3], I happen to be able to
decide that a single E. coli cell is an autopoietic system, whereas my
bicycle, a piece of cake, or my home city are not. I even know that a
multicellular organism may be more a problematic case, it may be a higher order
autopoietic system, but there is the possibility that "the observer is
mistaken" [Ref. 3, p. 108]. From reading selected thoughts about
self-organizing systems (from e.g., Simon, Prigogine, Jantsch, Salthe,
Kauffman, and Gell-Mann), I really know that a tornado, a bamboo plant, and a
city are examples of such systems whereas a watch, a dish, a rock, or a carbon
atom are not; and furthermore, that there seem to be borderline cases such as
the Earth, the solar system, a three-dimensional globulin macromolecule, and a
piece of crystal, all of which may be or may not be (considered as)
self-organizing, depending on the specific conditions. The reason for calling
attention to prototypes (which are normally considered as pertaining to pre- or
non-scientific contexts) is the suspicion that in some of the abstract
theorizing, the base exemplars are not described much better than by everyday
prototypes, and the pool of paradigmatic exemplars [4] indeed has a
prototypical character.
Experiential biology: Now, what do I know more about the bamboo
plant (as a concrete plant so to speak) when I can claim it to be a
self-organizing system? Only in the technical sense of conceptual
property-inheritance (known within programming and Artificial Intelligence)
will this add to by knowledge of bamboo biology. However, one could also say
that it is not really knowledge about the bamboo but about the abstract
property of self-organizing systems, a property that all plants, including the
bamboo, happen to share. The point is that in arguing about the theoretical
details about evolutionary systems (living self-organizing evolving
communicating systems) -- and about how to frame a general theory of such
systems -- we take for granted the findings of experimental biology and a lot
of (almost) tacit knowledge about what I would like to call experiential
biology. This includes the domain mentioned above as folk biology (common,
conventional, public, everyday notions of plants and animals) plus the
subjective field of our own experiences of what it means to be a growing,
feeding organism, a moving feeling animal, a sensitive human being. Thus in my
use of the word, experiential biology includes folk biology (which again
includes some, more or less non-darwinian, but very popular ideological notions
of 'higher' and 'lower' forms of life, and so forth) but first and foremost,
experiential biology includes a kind of subjective and qualitative knowledge of
the feeling of life, of sentience, of the moods of passive laziness or active
engagement, and so on. It is that part of a human umwelt that hardly can
be realized by a robot [5]. A passage that illustrates this qualitative
aspect of knowledge of complex living systems very well -- especially because
of its sympathetic sensuality and the concreteness in its description of
self-organization -- is a beautiful quotation from Denis Diderot's Le
Rêve de d'Alambert (1769), here quoted from Man's New Dialogue
with Nature by Prigogine & Stengers [Ref. 6, p. 81], the
passage where Diderot, in an imaginary conversation with d'Alambert, tries to
demonstrate the failure of a mechanist explanation:
"What is in this egg? An insensitive mass before the germ is put into it ... How does this mass evolve into a new organization, into sensitivity, into life? Through heat. What will generate heat in it? Motion. What will the successive effects of motion be? Instead of answering me, sit down and let us follow out these effects with our eyes from one moment to the next. First there is a speck which moves about, a thread moving and taking colour, flesh being formed, a beak, wing-tips, eyes, feet coming into view, a yellowish substance unwinds and turns into intestines--and you have a living creature.... Now the wall is breached and the bird emerges, walks, flies, feels pain, runs away, comes back again, complains, suffers, loves, desires, enjoys, it experiences all your affections and does all the things that you do. And you will maintain, with Descartes, that it is an imitating machine pure an simple? Why, even little children will laugh at you, and philosophers will answer that if it is a machine you are one too!"Diderot's appeal to the experiential biology of a chicken in formation is of double interest here: It illustrates the point, that in the discursive context of very theoretical arguments about system types and how to explain them, we make use of more intuitive kinds of knowledge when we examine the merits or the failure of such theories (whether they are mechanist as in Diderot's case or not). The sentient living thing, like the chicken, or like you and me, becomes a prototype of a complex system that has not yet been explained by mechanistic principles. The fact, that even children can tell the difference between a watch or other artificial devices and living beings, is a fact of folk biology; and the capacity to make that distinction, to recognize a system as alive, is constitutive for the very concept of an organism. Furthermore, in other passages in Prigogine and Stengers' book, we can observe the tendency to blur that distinction, to hide the pheno-ontological difference between the prototypes of eddies, plants, and animals, by emphasizing that they all are 'dissipative structures'. This hints at a general point:
Is our concept of an organism a closed one?
Having considered a peculiar epistemological aspect of the abstract nature of
the new complex-systems theories and their relation to concrete instances of
known species of life, the focus can now be directed at a related though more
intrinsic-theoretical question about the attempts to characterise complex
evolutionary systems.
Theoretical biology since Kant has invented several seemingly different
but very general ideas about what constitute a living system, for example,
metabolism, self-reproduction, evolution, hereditary information, code-duality,
autopoietic semantic and autocatalytic closure, emergence, and functionality of
parts in relation to a whole. I will now propose the apparently odd thought (1)
that these notions refer to the very same feature (or property cluster), and
furthermore, (2) that these general ideas are crucially dependent on the
triumphant development of experimental molecular biology in the twentieth
century.
As a caveat, it must be noted, that although a common idea or an everyday
concept may easily be expressed in various natural languages such as Danish or
English, it is not so evident that the same theoretical idea can be
expressed in distinct theoretical settings. Several arguments exist against
such a claim, for instance the notion of incommensurability between paradigms
that allows only partial translation of concepts from one paradigm to a
succeeding one, so the theoretical meaning of a term is not well preserved in
the process of translation. Nevertheless, it is still possible to imagine, in a
vague sense of sameness, that some fundamental characteristics of complex
living systems, characterized by distinct conceptual tools, somehow refer to
the same idea of what constitutes the most distinctive feature of a living
system.
Another way to state this idea is to say that distinct theoretical
perspectives abstract certain more or less crucial special features of 'real
living systems', or (to state the same proposition in a less naive-realist
mode) of some prototypical idea of living systems. We may posit a common
deep structure of these prototypes (corresponding to a common unitary whole of
characteristic processual properties of living systems) that we cannot see at
the surface level of everyday concepts, but which nevertheless is constitutive
of life as a generic phenomenon. Each specific theoretical paradigm then
abstracts certain aspects out of this deep level cluster of characteristics,
e.g., 'metabolism', 'the possession of a genetic code', 'autonomy',
'interaction with environment', 'interplay of self-organization and natural
selection', or whatever. Furthermore, this abstraction process takes place in
part by the hidden reference to certain system prototypes as explained above,
e.g., the BZ-reaction (or Turing patterns) as a prototype for emergence or
developmental order in embryogenesis, or the metabolism of a bacterial cell as
a prototype for the autonomy (or autopoiesis) of life as such.
In this note I will only consider a sub-set of about four general notions
related to the study of living systems:
1 Function as an explanatory tool of experimental biology and a philosophical argument for the autonomy of biology (or an embarrassment for some philosophers of science);
2 Emergence as an ontological notion covering all levels of organization from the physical to the mental, and considered to be an especially important aspect of understanding the origin of life because this process created special, new, unpredictable properties such as self-reproduction and evolution by natural selection;
3 Semantic closure and the concept of dual modes of complex systems in the theory of H. H. Pattee;
4 Biosemiosis as the defining feature of life, where biosemiosis means a sign interpretation process in living organisms [7].
To jump to the conclusion of this comparative analysis: It is conjectured that
biosemiosis presupposes functionality, that functionality is only possible
under a closure of operations, and that this closure is an emergent phenomenon
of a semiotic character. (If this is so, a synthesis is needed, and also an
epistemological clarification).
Thus, the null hypothesis to test, so to speak, alternative to the
conclusion just mentioned, is that these four notions of life are either
irreducibly incompatible or express four independent characteristics of life.
We go step by step:
(i) Biosemiosis presupposes functionality. The first step is to
assume that we have defined life in a semiotic way in some sense [7,
14].
To explain how, let me combine Peirce's notion of a sign with Bateson's
notion of information [cf., Ref. 15 and 25] to emphasize the relational
character of a biosemiotic process: Life entails semiosis as the action of
signs, where a sign is a first, i.e., a representamen that stands (by a code or
a habit) in such a relation to a second, its object, so as to determine a
third, its interpretant, to take the same relation to that object (that the
representamen takes) and thereby effecting that interpretant so that this
effect is significant (potentially or actual) to that interpretant's
interpreter organism, in the sense that it is a difference that makes a
difference to the interpreter. The interpreter must be an organism, a part of
an organism, or an organism-like entity, and the effects on that organism's
parts, to be significant (i.e., `to make a difference'), cannot be merely
physical, because by definition, the difference, if any, they make, is of
potential or actual purport or relevance to the organism in question, which
means that they concern the organism's chances of finding food or other sources
of energy, or that they ultimately concern its chances of surviving and
reproducing.
Admittedly, this is a more restricted sense of sign action that connects
the semiotic interpretant more closely to a material interpreter-organism (than
Peirce's sense of sign action; or than that found in Ref. 16; cf. Ref. 17).
Nevertheless, it shows the relation between, the parts of the semiotic process,
and the functionality of the organism as a whole in relation to that organism's
biophysical parts: Were there no organisms -- or no functional parts of the
organism that contributes to maintain the organism as a whole (where each part,
as it were [and as it evolutionary is], exists for the purpose of the whole, as
Kant pointed out) -- there would be no action of signs. In this sense, sign
function and biofunctionality of organisms are intrinsically related. (Of
course, on higher levels of organization, anthroposemiotic processes may
display a semiotic functionality that only indirectly presupposes
biofunctionality; for example, the Internet as a growing semiotic web functions
to connect many computers in a huge virtual library, that may be described
linguistically or sociologically, and only ontologically presupposes the
biofunctionality of the brains of their human designers and users). The hidden
prototype of a basic biosemiotic system is the simple prokaryotic cell.
(ii) Functionality is only possible under a closure of operations.
In this note I cannot comment upon the body of philosophical research done on
the notion of function in biology (but see Ref. 18), and I shall simply assert
that basically, the notion of function in biology is the teleological (and
mereological) notion of "a part existing for the good of the whole", or "having
the purpose of" doing something in relation to the whole. This is the case
disregarding whether the whole is intentional or not, and disregarding whether
or not the notions of purpose, and `the good of' (and the related complex of
function-ideas) in principle, theoretically, may be reduced to mechanistic
causal explanations in a historical setting, e.g., in a neo-Darwinian setting.
There are serious reasons for assuming such a reduction as impossible, even in
principle, but I do not go into that here.
Instead, I will claim that the reason why functionality is only possible
under a closure of operations is astonishing simple (if I have fooled myself
here, I hope to learn how). Only when the causal chain from one part to the
next closes or feeds back in a closed loop -- at once a feed-back on the level
of parts and an emergent function defined (as mentioned) as a part-whole
relation -- can we talk about a genuine function. In other words: It is because
function is the function of a part that works effectively to produce (part-part
efficient causation) influences on other parts within the same whole (the same
form, the organism's) -- where each part is constrained by the same whole
(formal causation) -- the total of parts interacting under these constraints in
a coherent emergent pattern is the whole organism, whose maintenance
(final causation) as form is the goal of each part. Here, final causation --
i.e., the dual process of downward constraints (formal cause) on the
behaviour of the parts and the emergent pattern of the parts forming a
functioning organism (final causation), which is made of parts (material
causation) -- is the causation of a physical part within a biological whole
being committed to a specific role in the internal organization of that whole,
thus the internal ascription (de re) of a role to the part is the
emergence of that part's function. Consider a newly transcribed polypeptide
chain in a cell before it folds (by self-assembly or with the help of protein
chaperones) into an enzyme: This physical thing has not yet an actual function,
only a potential one as a finished part, that is, an enzyme. As a physical
thing, the enzyme is just a complex molecule; as a biochemical thing, the
enzyme is a functional part of the cell's metabolism which, in addition to the
membrane and the DNA code, makes up the very cell! Function can only be
cell-organized, so to speak, not simply 'physically self-organized'. (Again we
can observe: The hidden prototype is [in the twentieth century] the cell, or
[in the twentieth and nineteenth century] the organism).
(iii) Closure is an emergent phenomenon. This is in part implied in
the previous development: Only by analysing a system in terms of minimally a
higher and a lower level (a whole with some parts) can one identify
functionality as based on the causal closure of operations; this functional
causality being emergent (as defined in Ref. 19) upon the local
part-to-part interactions of the individual parts (efficient causality) within
that whole. A further comment: Closure has been used as a predicate in quite
different circumstances (see other contributions to this volume), and denote
quite different concepts. Here it is used and defined in the biological realm,
and is not merely informational, or organizational, but also material and
energetic, and thus biologic closure is never perfect (compare Ref. 20).
(iv) Closure in biosystems is of a semiotic character. As an
imperfect emergent phenomenon, the closure of operations between parts in
organisms is producer of differences that makes differences to the parts as
well as to the whole organism. Thus, endosemiotic sign links can be analysed as
causal links between functioning parts that regulate the entire organic
machinery of the body. But, one could object, by what necessity should an
organic complex device with the property of emergent functionality be of a
semiotic character? This is the deepest and most difficult question and I shall
only sketch two possible answers, one of metaphysical necessity, the other of a
fact-like or law-like necessity: (1) the Peircean (metaphysical) answer:
Wherever Nature takes on so complex habits that allow for the existence of
living feeling, the intensity of mind has grown high enough to generate the
action of thirdness characteristic of genuine triadic sign action [16,
21]. (As few scientists are familiar with Peirce's philosophy, few will
accept this answer I'm afraid). (2) the von Neumann-Schrödinger answer
(termed so to emphasize that it is a reconstruction of their original arguments
combined with contemporary molecular biology): The minimal complexity of a
system which does not spontaneously degenerate but complexifies further by
open-ended evolution [Ref. 22, p. 80] is exactly the first self-organizing
system (`feeding on negative entropy') with an internal semiotic structure, an
internal 'code-script' [23]. The endosemiotic nature of the code is the
fact that it (biochemically) embodies an internally defined mapping from a
nucleotide sequence space to a protein sequence space within the system. Were
there no code (and memory) of this kind, there would be not enough biochemical
specificity ('information') in the closed structure of reactions, and the
system would fall below the threshold and degenerate. This may be related to
unknown 'laws of complexity'. Due to lack of present knowledge about primitive
kinds of metabolisms (covering the continuum "no life--primordial life--life"),
this answer may be read as a not yet proven hypothesis open to scientific
investigation.
To sum up: biosemiosis presupposes functionality, and functionality is
only possible under a closure of operations. The prototype organism at this
level of research is a single cell, its parts forms the endosemiotic network,
and the membrane parts make that organism receptive also to changes in the
ambient reservoir of significant influences. This closure is an emergent
phenomenon of a semiotic character, and as a closure, it is only
partial, imperfect, relatively open. Therefore we can conclude (a) Synthesis is needed. (b) Further epistemological clarification of
these concepts is needed too. (c) A null hypothesis -- that the four notions of
life, they are, biosemiosis, functionality, emergence, and closure, express
four independent characteristics of life -- has been refuted.
Acknowledgements
I'll express my thanks for inspiration to contributors of the evolutionary systems volume [24] as well as the participants in the closure workshop in Ghent in May 1999. I claim no special novelty of the ideas expressed in this note and take the sole responsibility for its opaqueness and incompleteness.
[*] [note added in proof]: I mean scientism in the usual sense of "these doctrines, outlooks and associated forms of social practice extending to science an authority beyond its legitimate scope" (from the entry on scientism in: W.F. Bynum, E.J. Browne & Roy Porter, eds. (1981): Dictionary of the History of Science. Macmillan Press, London.)
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