James Barham University of Notre Dame & Institute for the
Study of Nature June 18, 2009
Slide 2
Goals of This Lecture To argue that: There is a Life/Body
Problem analogous to the Mind/Body Problem Contemporary work in
nonlinear dynamics and condensed-matter physics may offer a way of
understanding the Life/Body Problem in terms of the emergence of a
living phase of matter
Slide 3
Claim: Just as there is a widely acknowledged problem relating
mind to its material substrate (the brain), so too is there a real
problem relating life to its material substrate (the membranes,
organelles, enzymes, etc. constituting the cell).
Slide 4
What the Problem Is It looks like living things possess
something like preferences (values) and goals (purposes) as an
organizing principle Neutrophil phagocytosis
http://www.youtube.com/watch?v=fpOxgAU5fFQ Modern biological
science claims to give an exhaustive account of life without
reference to value or purpose If modern biology is right, there is
no value or purpose in life as such Still leaves possibility of
emergence higher up But if the intuition that life as such involves
value and purpose is right, then our scientific account is
incomplete Natural science option? Here, I will argue that our
scientific account of life is incomplete
Slide 5
Current Account 1 There is no essence of life Just a list of
more or less general properties: Metabolism Growth Responsiveness
to stimuli Reproduction Ability to evolve Etc.
Slide 6
Current Account 2 Cells are machines Like automobiles and
computers All of the parts of the cell (phenotype) are generated
mechanically by the genotype (DNA) Central Dogma: DNA RNA Proteins
DNA carries the information for the cell The machinery of the cell
is regulated by feedback mechanisms (cybernetic control)
Slide 7
Conventional Account 3 The complex machinery of the cell was
put into place gradually by Natural Selection Random genetic
mutation New parts of the cell machinery come into being by chance
Survival of the fittest If a new part just happens to increase a
cells probability of survival and reproduction relative to
competing cells in a population, then gradually cells containing
that part will come to dominate the population
Slide 8
Challenging the Current Account I will argue that many aspects
of the Current Account are mistaken: Life does have an essential
nature I call the essential nature of life functional stability
Cells are categorially different from manmade machines Machines are
not functionally stable in the way that cells are Cell regulation
is not fully explained by cybernetic control theory Natural
selection cannot explain the deep conceptual problems with life The
Central Dogma is probably wrong (Jablonka & Raz 2009; Shapiro
forthcoming) Even if genotypic change were mostly random, phenotype
construction is clearly goal-directed ( West-Eberhard 2003; 2005),
so phenotype variation is not random
Slide 9
The Big Problem There is one big problem underlying all the
other problems with the Current Account of life Non-living things
(e.g., mountains) may endure for long periods of time But living
things manipulate matter selectively, drawing on internal energy
stores, in order to endure In short, living systems have an
intrinsic preferred state : namely, self-preservation (token or
type) Ordinary physical principles by themselves (e.g., free energy
minimization) cannot explain this fact I will argue that neither
cybernetic control theory nor selection theory helps
Slide 10
The Essence of the Big Problem There are many ways to express
the nature of the Life/Body Problem The essence of the problem
seems to me to be to give some sort of scientific account of a set
of interlocking conceptual features of life and action: Value
Purpose Instrumental Ought I call this the Normative Nexus
Slide 11
The Normative Nexus Living things seem to prefer existence over
non-existence This preference creates value distinctions Whatever
contributes to self-preservation is good; whatever hinders self-
preservation is bad Living things must act in order to maintain
themselves in existence Action occurs according to means-end logic
Action strives towards particular ends or goals (is inherently
purposive) Actions may or may not succeed (attain their purpose) To
succeed, the means chosen must be appropriate to the end Thus, life
operates under the hypothetical imperative (or instrumental ought)
If you want to achieve X, then you ought to do Y This set of
interlocking phenomena value, purpose (or teleology), and
instrumental ought (or normativity) may be called the Normative
Nexus
Slide 12
The Big Objection But there is a big objection to this view:
Sure, we all talk about life as though it operated according to the
Normative Nexus See almost any page of any textbook But most
scientists believe that is just a metaphor, a convenience, a faon
de parler After all, we already have a perfectly good theoretical
framework in place that reduces normativity Dont we?
Slide 13
Reducing Normativity The Current View claims to reduce
normativity in two basic ways Cybernetic control theory explains
how it is possible for organisms to behave in an apparently
goal-directed way The theory of natural selection explains how
cybernetic control systems come to exist naturally
Slide 14
Cybernetic Control Begs the Question The purpose of a
thermostat-furnace system is to maintain ones house at a certain
temperature This purpose is attained thanks to a particular
organization Call this particular organization good-repair
Good-repair is imposed on the system by us We determine which
organization counts as good-repair There is no principle internal
to the system that causes either the thermostat or the furnace to
preserve itself in good-repair Good-repair maintained via rigidity
of parts Thermostats and furnaces do not prefer the state of
good-repair Conclusion: The concept of cybernetic control begs the
question of normativity Ditto for the concept of information in
biology
Slide 15
Selection Theory Also Begs the Question Before new organic form
can be selected, first it must exist Natural selection creates
nothing; it amplifies what already exists Functional organization
of organism is always already assumed to exist by the logic of
selection theory Furthermore, even if the Central Dogma is true,
any random change at the level of genotype must still be
constructed into a phenotype This construction means functionally
integrating the new part into the existing organization of the cell
Conclusion: The principle of natural selection begs the question of
normativity
Slide 16
Positive Evidence Needed Even if it is true that cybernetic
control and selection theories do not fully reduce normativity
Still, it would be nice if there were some positive evidence in
favor of my claim that the Normative Nexus is something objectively
real There is
Slide 17
Metastability of Life Consider the following facts: Living
things are capable of recovering their dynamical equilibrium
following perturbation to some extent (robustness) Developmental
trajectories Wound repair Living things are capable of finding
entirely new dynamical equilibria following perturbation
(plasticity) Slijpers goat and friends Let us call robustness and
plasticity together by the name bio- metastability
Bio-metastability is a normative concept Presupposes a preferred
state of the organism However, we still need proof that natural
selection cannot explain all the specific forms of
bio-metastability
Slide 18
Slijpers Goat and Friends West-Eberhard (2003, 2005) describes
the case of Slijpers goat Here is a very similar case we can see
with our own eyes: Faith the Dog:
http://www.youtube.com/watch?v=aZsV4R3XJKk
http://www.youtube.com/watch?v=aZsV4R3XJKk Other examples: Martin
Heisenbergs flies (Heisenberg & Wolf 1984; 194204) Mriganka
Surs ferrets (Sharma et al. 2000) Note that: All these examples
exemplify the Normative Nexus Natural Selection cannot possibly
explain them
Slide 19
The Point of the Examples Conclusions: Most living behavior is
dynamically constructed by the organism interacting with the
environment (Jirsa & Kelso 2004; Juarrero 1999; Warren 2006)
Behavioral plasticity implies anatomical/physiological plasticity
Plasticity is an intrinsic property of living systems as such
Plasticity (or, more generally, Bio-Metastability) exemplifies the
Normative Nexus The Normative Nexus is an aspect of Lifes essential
nature
Slide 20
Need for a Unifying Physical Principle All of this leads to a
further conclusion: There must be a unifying physical principle
underlying the functional activity of living systems Here is a
brief argument leading to the same conclusion: All enduring natural
physical systems are governed by an underlying stability principle
(together with constraints) Cells are enduring natural physical
systems Therefore, cells are governed by an underlying stability
principle
Slide 21
Functional Stability Principle What can we say about this
principle? The most important thing to recognize is that it is
distinct from ordinary physical principles operating at the
macroscopic level, which at bottom boil down to free energy
minimization The stability principle underlying life is different
Living stability is achieved by means of the coordination of
functional actions Let us call this principle functional
stability
Slide 22
What Ive Tried to Show So Far The chief properties of life that
distinguish cells and other organisms from inanimate matter are:
Normative Nexus Bio-Metastability These properties are objectively
real, and require scientific explanation They cannot be explained
by either cybernetic control or selection theory (because both
theories presuppose preferred states) To explain them, we need to
posit the existence of an underlying principle of functional
stability The principle of functional stability provides us with an
essence of life and a solution to the Life/Body problem But what is
the principle of functional stability, from a physical point of
view?
Slide 23
Claim: Life may be a manifestation of a particular kind of
condensed matter (the living phase of matter), and, if so, then it
may be explainable via a particular conception of emergence.
Slide 24
The Problem with Microphysical Reduction Scientists often show
why a thing, N, has the properties or causal powers that it does by
showing how Ns parts, M 1, M 2, M j, work together to produce N
Call this microphysical reduction Microphysical reduction seems to
show that the apparent causal powers of N have been shown actually
to reside in its parts Baseball example Causal power has drained
away from level N to level M But it is plausible to think that what
is real has causal powers Alexanders dictum So, if level N has no
causal powers of its own, it seems justified to deny that is real
So, N can be eliminated from our scientific world picture But the
same procedure can be repeated for level M, as well; etc. So,
nothing is real except the fundamental level (quarks, or
whatever)
Slide 25
Eliminativism vs. Emergence Someone who cheerfully accepts this
argument is called an Eliminativist To most folks, though, the
conclusion that nothing is real but quarks seems absurd The
question is: How should we understand the relationship between a
thing and the parts that comprise it? The Emergentist replies: Some
kinds of wholes are just the sum of their parts Other kinds of
wholes have causal powers that are not merely the sum of the
contributions of their parts
Slide 26
Definition of Emergence So, the doctrine of emergence is
basically just the denial of eliminativism It says: For some kinds
of wholes, the whole (level N) has causal powers above and beyond
what is contributed by all of the individual parts (level M) But
this idea has conceptual problems of its own
Slide 27
The Problem with Emergence Traditionally, there have two been
kinds of objections to emergence: N-level causal powers seem
inexplicable Brute fact, magic, pixie dust, etc. N-level causal
powers imply downward causation, which many find incoherent
Downward causation means: N-level causally affects M-level But how
can N-level causally affect M-level when M-level is required to
produce N-level in the first place? Margaret Morrisons (2006)
theoretical principles view of emergence provides answers to both
objections
Slide 28
Answering the Brute Fact Objection Morrrison (2006) points to
what she calls theoretical principles that are used to explain how
stable states of matter can exist and yet be insensitive to the
details of the lower-level dynamics Spontaneous symmetry breaking
Renormalization Group Critical phenomena (phase transitions, etc.)
Effective field theories She writes (ibid.; 882) : The relation to
higher level theoretical principles like symmetry breaking and
localization shows that certain kinds of stable behavior, though
not derivable from fundamental theory, can nevertheless be
explained in a systematic way, one that doesnt rely on the
contingencies of particular situations. On this account, emergent
properties not just a brute fact
Slide 29
Answering the Downward Causation Objection Morrison (ibid.;
883) also mentions the way in which phonons are produced as a
collective feature of a large number of atoms condensed into a
crystal The N-level (crystal) has properties (phonons) that the
M-level (atoms) lack She does not put it like this, but it is clear
from the example that causation is the wrong way to think about the
relation between M-level and N-level It is not that the atoms make
individual contributions to the causal powers of the crystal
Rather, the atoms collectively constitute a different kind of
entity with new causal powers On this view, constitution, not
causation, is the correct relation between M-level and N-level In
that case, downward causation of N-level onto M-level is logically
consistent
Slide 30
Emergence and Life One last question remains: How can we apply
the theoretical principles view of emergence to the living phase of
matter? Is such an idea even remotely plausible, from an empirical
point of view?
Slide 31
Aspects of the Living Phase of Matter Cytoplasm has the
following characteristics: Extreme crowding (Luby-Phelps 2000;
Wheatley 2003) Gel-like properties (Pollack 2001)
Liquid-crystal-like properties (Ho et al. 1996) Phase transitions
important to macromolecular function (Pollack 2001; Pollack &
Chin 2008) In addition, proteins are: Dynamically active
(frustrated) systems (Frauenfelder et al. 1999) Functionally
coupled to the cytoplasm (Frauenfelder et al. 2009) These facts
support the idea that Morrisons theoretical- principles-based
emergence may be involved in the living phase of matter
Slide 32
Conclusion This statement by the Japanese systems biologist,
Hiroaki Kitano (2007; 3), nicely summarizes what is needed: The key
issue is whether it is possible to find a formalism in which
robustness and its trade-offs could be defined so that robustness
is a conserved quantity If such a formalism could be found, then a
rigorous theory of functional stability might be possible The best
hope for this would seem to lie in extending the theoretical
principles of condensed-matter physics to encompass the living
phase of matter In that case, a solution to the Life/Body Problem
on the basis of emergence would be within reach
Slide 33
Frauenfelder, Hans, Peter G. Wolynes, and Robert H. Austin
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Paul W. Fenimore, Helen Jansson, Benjamin H. McMahon, Izabela R.
Stroe, Jan Swenson, and Robert D. Young (2009) A Unified Model of
Protein Dynamics, Proceedings of the National Academy of Sciences,
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Gal Raz (2009) Transgenerational Epigenetic Inheritance:
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Slide 34
References (cont.) Jirsa, V.K. and J.A.S. Kelso, eds. (2004)
Coordination Dynamics: Issues and Trends. Berlin: Springer.
Juarrero, Alicia (1999) Dynamics in Action: Intentional Behavior as
a Complex System. Cambridge, MA: Bradford Books/MIT Press. Kitano,
Hiroaki (2007) Towards a Theory of Biological Robustness, Molecular
Systems Biology 3: article number 137. Luby-Phelps, K. (2000)
Cytoarchitecture and Physical Properties of Cytoplasm: Volume,
Viscosity, Diffusion, Intracellular Surface Area, in H. Walter,
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Margaret (2006) Emergence, Reduction, and Theoretical Principles:
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Pollack, Gerald H. (2001) Cells, Gels, and the Engines of Life.
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Shapiro, James A. (forthcoming) Revisiting the Central Dogma in the
21 st Century. (available online)
Slide 35
References (cont.) Sharma, J., A. Angelucci, and M. Sur (2000)
Induction of Visual Orientation Modules in Auditory Cortex, Nature
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