1,023 research outputs found
Contextual emergence of intentionality
By means of an intriguing physical example, magnetic surface swimmers, that
can be described in terms of Dennett's intentional stance, I reconstruct a
hierarchy of necessary and sufficient conditions for the applicability of the
intentional strategy. It turns out that the different levels of the intentional
hierarchy are contextually emergent from their respective subjacent levels by
imposing stability constraints upon them. At the lowest level of the hierarchy,
phenomenal physical laws emerge for the coarse-grained description of open,
nonlinear, and dissipative nonequilibrium systems in critical states. One level
higher, dynamic patterns, such as, e.g., magnetic surface swimmers, are
contextually emergent as they are invariant under certain symmetry operations.
Again one level up, these patterns behave apparently rational by selecting
optimal pathways for the dissipation of energy that is delivered by external
gradients. This is in accordance with the restated Second Law of thermodynamics
as a stability criterion. At the highest level, true believers are intentional
systems that are stable under exchanging their observation conditions.Comment: 27 pages; 4 figures (Fig 1. Copyright by American Physical Society);
submitted to Journal of Consciousness Studie
Spurious, Emergent Laws in Number Worlds
We study some aspects of the emergence of logos from chaos on a basal model
of the universe using methods and techniques from algorithmic information and
Ramsey theories. Thereby an intrinsic and unusual mixture of meaningful and
spurious, emerging laws surfaces. The spurious, emergent laws abound, they can
be found almost everywhere. In accord with the ancient Greek theogony one could
say that logos, the Gods and the laws of the universe, originate from "the
void," or from chaos, a picture which supports the unresolvable/irreducible
lawless hypothesis. The analysis presented in this paper suggests that the
"laws" discovered in science correspond merely to syntactical correlations, are
local and not universal.Comment: 24 pages, invited contribution to "Contemporary Natural Philosophy
and Philosophies - Part 2" - Special Issue of the journal Philosophie
The low noise phase of a 2d active nematic
We consider a collection of self-driven apolar particles on a substrate that
organize into an active nematic phase at sufficiently high density or low
noise. Using the dynamical renormalization group, we systematically study the
2d fluctuating ordered phase in a coarse-grained hydrodynamic description
involving both the nematic director and the conserved density field. In the
presence of noise, we show that the system always displays only quasi-long
ranged orientational order beyond a crossover scale. A careful analysis of the
nonlinearities permitted by symmetry reveals that activity is dangerously
irrelevant over the linearized description, allowing giant number fluctuations
to persist though now with strong finite-size effects and a non-universal
scaling exponent. Nonlinear effects from the active currents lead to power law
correlations in the density field thereby preventing macroscopic phase
separation in the thermodynamic limit.Comment: 17 pages, 5 figure
Generating functional analysis of complex formation and dissociation in large protein interaction networks
We analyze large systems of interacting proteins, using techniques from the
non-equilibrium statistical mechanics of disordered many-particle systems.
Apart from protein production and removal, the most relevant microscopic
processes in the proteome are complex formation and dissociation, and the
microscopic degrees of freedom are the evolving concentrations of unbound
proteins (in multiple post-translational states) and of protein complexes. Here
we only include dimer-complexes, for mathematical simplicity, and we draw the
network that describes which proteins are reaction partners from an ensemble of
random graphs with an arbitrary degree distribution. We show how generating
functional analysis methods can be used successfully to derive closed equations
for dynamical order parameters, representing an exact macroscopic description
of the complex formation and dissociation dynamics in the infinite system
limit. We end this paper with a discussion of the possible routes towards
solving the nontrivial order parameter equations, either exactly (in specific
limits) or approximately.Comment: 14 pages, to be published in Proc of IW-SMI-2009 in Kyoto (Journal of
Phys Conference Series
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