Prof. James Griesemer will be giving a talk on “Life cycle models and origins-of-life scenarios: A reproducer perspective”.

Date and Venue: 20th October 2011, at 11:00, Seminar room – Dept of Logic and Philosophy of Science.

Abstract: A key feature of cellular living systems is organization of life trajectories into cycles. A now common view of the minimal organization of living systems — “chemoton” organization (Gánti 1971, 2003) — characterizes living systems in terms of three autocatalytic subsystems: a metabolic subsystem, a template hereditary subsystem, and a membrane boundary subsystem. Szathmáry and colleagues (e.g. Fernando et al. 2005, Fernando and Szathmáry 2009) investigate a variety of “infra-biological” systems that have some but not all components of chemoton organization. One or more of these may have emerged in possible chemical evolutionary routes to a biological protocell (Griesemer and Szathmáry 2010). In this talk, I consider the aim of such work to characterize the space of possible living systems in terms of the reproducer perspective on units of heredity, development and evolution (e.g. Griesemer 2000). I argue that it is important to recognize the role of theoretical perspectives in guiding the ways scientists track phenomena of interest. Different tracking perspectives lead to different evaluations of models and evidence. In origins of life research, replicator-, metabolism-, and boundary-first perspectives involve commitments about what sorts of chemical and molecular variation are worth tracking through life cycles to discover potential units of evolution. These commitments in turn govern choices of resolution in models of life cycles that guide and constrain judgments about important properties of proto-biological systems, such as whether they involve limited vs unlimited heredity or holistic vs modular replication. I offer some reflections on a recent argument by Vasas, Szathmáry and Santos (2010) that certain kinds of systems with “compositional” rather than “alphabetic” hereditary subsystems (e.g. GARD, Lancet and colleagues) cannot sustain fitter types by selection to illustrate the value of the reproducer perspective. 

Friday 3 December, 2010, 11:30

The Location of Subjective Information

Dr Michael Beaton, University of Sussex

Using Tononi’s Information Integration Theory of consciousness as a
jumping off point, I will critically examine the claim that internal neural
states carry information for the subject. I will review Edwin Jaynes’
presentation of Cox’s Theorem, which demonstrates that the laws of
probability are the only consistent way to mathematically capture reasoning
in the face of uncertainty. Also following Jaynes, I will argue that
Shannon information is intimately bound up with probability, and that
information for a subject exists whenever subjective probabilities exist.
Therefore, I will suggest, information for a subject inheres in the
structure of a subject’s rational behaviour. I will argue that internal
information in neural states is always derivative (information for a
theorist) – even though dynamic neural complexity can be a crucial part of
the explanation of richly structured rational behaviour. Some important
clarifications will be noted. Firstly, the rationality in question here is
practical rationality (coherent, meaningful behaviour in the world) and not
abstract theoretical rationality. Secondly, whilst probability theory
provides rules which a rational subject should not breach, it does not
provide a full set of rules for ‘how to be rational’. Indeed, it remains
possible that rationality as such can never be fully captured in rules.
Finally, even though rationality inheres in a subject’s pattern of
behaviour, there are good reasons to think that the structures of the world
responsible for a subject’s rational behaviour extend beyond the subject’s
body; we should not expect to find rules of rationality encoded anywhere
inside a rational subject.