Björn Brembs

On our final day ([day
1](https://bjoern.brembs.net/2015/11/chance-in-animate-nature-day-1/),
[day
2](https://bjoern.brembs.net/2015/11/chance-in-animate-nature-day-2/)),
I was only able to hear [Boris
Kotchoubey](https://www.zpid.de/psychauthors/index.php?wahl=forschung&uwahl=psychauthors&uuwahl=p00799BK)'s
(author of "[why are you
free?](https://www.amazon.com/Why-Are-You-Free-Neurobiology/dp/1619425343/ref=sr_1_1?s=books&ie=UTF8&qid=1447318435&sr=1-1)")
talk, as I had to leave early to catch my flight. He made a great effort
to slowly introduce us to nonlinear dynamics and the consequences it has
for the predictive power of science in general.

Applied to human movement in particular, he showed that nervous systems
take advantage of the biophysics of bodily motion to only add the
component to movement, that biophysics (think your leg swinging while
you walk) doesn't already take care of. This is an important and all too
often forgotten insight that I recognize from the work of the laboratory
of [Hillel Chiel](https://biology.case.edu/faculty/hillel-chiel/) in
*Aplysia* biting behavior. He explained work studying hammer blows,
where the trajectory of all arm joints did not seem to follow any common
rules -- the only commonality that could be found between individual
hammer blows was the trajectory of the hammer's head. This is
reminiscent of the distinction between world- and self-learning in
flies, where the animals can use any behavior very flexibly to
accomplish an external goal, until they have performed the behavior
often enough to become habitual, at which time this flexibility is
(partially?) lost.

Halfway through the talk, he arrived at the [uncontrolled manifold
hypothesis](https://en.wikipedia.org/wiki/Motor_coordination#Uncontrolled_manifold_hypothesis),
where the nervous system isn't trying to eliminate noise, but to use it
to its advantage for movement control. Not entirely unexpectedly, he
went from this to
[chemotaxis](https://chemotaxis.biology.utah.edu/Parkinson_Lab/projects/ecolichemotaxis/ecolichemotaxis.html)
in *Escherichia coli* as an example of a process which also takes
advantage of chance.

He differentiates between two different kinds of unpredictable systems:
a) highly complex and incomputable systems b) unique unrepeatable
systems. The differences between these two systems breakdown as soon as
the uncertainly principle is an actual property of the universe that
poses absolute, non-circumventable limits on the potential knowledge
anyone can have about these systems.


On our final day (day 1, day 2), I was only able to hear Boris Kotchoubey‘s (author of “why are you free?“) talk, as I had to leave early to catch my flight. He made a great effort to slowly introduce us to nonlinear dynamics and the consequences it has for the predictive power of science in general.

Chance in animate nature, day 3

While the first day (day 2, day 3) was dominated by philosophy, mathematics and other abstract discussions of chance, this day of our symposium started with a distinct biological focus.
<strong>
 Martin Heisenberg, Chance in brain and behavior
</strong>
First speaker for this second day on the symposium on the role of chance in the living world was my thesis supervisor and mentor, Martin Heisenberg.

Chance in animate nature, day 2

[Ulrich
Herkenrath](https://www.uni-due.de/zim/services/suchdienste/mitarbeiter.php?id=1170),
a mathematician working on stochasticity, convened a tiny
[symposium](https://www.uni-due.de/de/presse/meldung.php?id=9145) of
only about a dozen participants discussing the role of chance in living
beings. Participants included mathematicians, philosophers and
neurobiologists.

**Herkenrath: "Man as a source of randomness"**

Herkenrath kicked off the symposium with his own presentation on "Man as
a source of randomness". He explained some principal insights on
stochasticity and determinism as well as some boundary conditions for
empirical studies on stochastic events, emphasizing that deterministic
chaos and stochasticity can be extremely difficult to empirically
distinguish.

In a short excursion, he referred to [Nikolaus
Cusanus](https://en.wikipedia.org/wiki/Nicholas_of_Cusa), who found that
no two subsequent situations can ever be exactly identical, our
knowledge being thus essentially conjecture. Apparently, Cusanus was
already proposing to falsify hypotheses as a means to approaching
'truth'. Not surprisingly, he immediately referred
to [Popper](https://en.wikipedia.org/wiki/Karl_Popper#Falsifiability.2Fproblem_of_demarcation)
with regards to the modern scientific method. Equally expectedly, when
he started talking about kinds and sources of chance, he talked about
quantum mechanics.

Moving from inanimate to living nature, he proposed amplifications of
quantum chance to the macroscopic level as sources of objective
randomness in the mesocosm, always emphasizing the difficulties in
distinguishing between such events and events that only seem random due
to our limited knowledge.  Contrasting two hypotheses of a deterministic
world and one where objective randomness exists, he mentions the
illusory nature of our subjective impression of freedom of choice. He
never got into the problem that quantum randomness, if only amplified,
leaves much to be desired in terms of decision-making. Essentially, he
seemed to be arguing that a deterministic world would be a sad place in
which he doesn't want to live, so he rejects a deterministic world. I've
never found this all too common argument very convincing.

Notably, Herkenrath mentioned that organisms are more than matter. Not
sure what to make of this. He defined autonomy as the ability to make
decisions that are not determined by the environment. Herkenrath went on
to describe classes of decisions, such as subconscious and conscious
decisions. How brains make these different forms of decisions will be
featured in different talks at the symposium. Herkenrath defined a third
class of decisions those that have come about by explicit (subconscious
or conscious) randomization. A fourth class is proposed, where a uniform
distribution is consciously generated, e.g. a human using a lottery.

**Falkenburg: "Causality, Chance and Life"**

The second speaker of the first day was
[Brigitte](https://de.wikipedia.org/wiki/Brigitte_Falkenburg)
[Falkenburg](https://ifpp.fk14.tu-dortmund.de/cms/ifpp/de/personen/professoren/falkenburg.html),
author of "[Mythos](https://www.springer.com/de/book/9783642250972)
[Determinismus](https://www.amazon.de/Mythos-Determinismus-Wieviel-erkl%C3%A4rt-Hirnforschung/dp/3642250971)"
([book
critique](https://www.spektrum.de/rezension/mythos-determinismus/1167888)).
She started out wondering how neural determinists understand evolution.

In Falkenburg's tour de force through the idea history of chance and
necessity, we first learned that the concept of chance itself can be
traced back to
[Leibniz](https://en.wikipedia.org/wiki/Gottfried_Wilhelm_Leibniz), who
described events that may have happened otherwise. Leibniz claimed in
his metaphysics that objective chance does not exist, as the whole world
is rational and determined. According to Leibniz, everything has a
[sufficient
reason](https://en.wikipedia.org/wiki/Principle_of_sufficient_reason).
In a very scholarly segue mentioning the dispute between Leibniz and
[Newton](https://en.wikipedia.org/wiki/Isaac_Newton) about who invented
calculus, she moved to the relationship between the laws of nature and
chance. [Kant](https://en.wikipedia.org/wiki/Immanuel_Kant) extended
Newtons mechanistic laws from the solar system to the entire universe
([Kant-Laplace
hypothesis](https://en.wikipedia.org/wiki/Nebular_hypothesis)). In his
"critique of pure reason" Kant later concluded that Leibniz's
'sufficient reasons' are better described as 'causes' and formulated the
principle of causality as an 'a priori' of human thinking. This was the
start of the demand for causal explanations in the empirical sciences:
science never stops asking for causes. However, Kant's critique did not
fully pervade the subsequent thinking, leading instead to
[Laplace](https://en.wikipedia.org/wiki/Pierre-Simon_Laplace)'s
determinism. Laplace was convinced that our insufficient knowledge is
the only reason for apparent (subjective) randomness, and a more
knowledgeable intelligence would be able to tell the future (cf.
[Laplace's demon](https://en.wikipedia.org/wiki/Laplace's_demon)).

With this backdrop of the idea history of causality, Falkenburg went on
to discuss modern concepts of causality away from equating it with
determinism. Both [Hume](https://en.wikipedia.org/wiki/David_Hume) and
Kant defined causality as a mode of thinking, i.e., psychologically,
rather than as a property of the universe. According to them, a causal
relationship between events is subjective rather than objective.
[Mill](https://en.wikipedia.org/wiki/John_Stuart_Mill)'s and
[Russell](https://en.wikipedia.org/wiki/Bertrand_Russell)'s positivism
later did away with causality as "a relic of a bygone era" (Russell).
One argument is that a cause can be seen as just a natural law and the
initial state of a system. Deterministic laws are invariant to a
reversal of time -- as such,causes can also lie in the future.

Today's philosophical variants of causality concepts reflect this
comparatively weak view of causality, which are very different from the
way we scientists would intuitively understand it. In a short discussion
of the concept of causality in physics, she quickly went through
classical mechanics, thermodynamics and quantum mechanics and special
relativity, emphasizing that we still do not have a theory unifying
these different approaches (she called it 'patchwork physics').

Towards the end, Falkenburg discussed the connection between causality
and time, emphasizing that the arrow of time cannot have a deterministic
basis and all deterministic laws are time reversible. As such, extreme
determinism comes with a high metaphysical price: time becomes an
illusion. According to Falkenburg, causality is hence not the same as
determinism: a causal process is not necessarily deterministic, it can
be composed of determinate and indeterminate components. Thus, if you do
not think time is an illusion and all possible outcomes coexist,
causality does not imply determinism and chance can be a cause as in,
e.g. evolution.

At the very end she mentioned
[Greenfield](https://en.wikipedia.org/wiki/Susan_Greenfield,_Baroness_Greenfield)
and the limits of the natural sciences in reducing consciousness to
materialism. I'm starting to get the impression that rejecting
determinism all too often goes hand in hand with woo peddling. Why is
that?


Ulrich Herkenrath, a mathematician working on stochasticity, convened a tiny symposium of only about a dozen participants discussing the role of chance in living beings. Participants included mathematicians, philosophers and neurobiologists.

Rogue Scholar Beiträge

Chance in animate nature, day 3

Chance in animate nature, day 2

Chance in animate nature, day 1