International Society for History, Philosophy, and Social Studies of Biology

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THURSDAY, JULY 9  /  15:30 - 17:00  /  DS-M280
Individual papers
Models, Theories and Computation

The strategies for morphology formation model building of ammonites

Ryota Morimoto (Health Sciences University of Hokkaido, Japan)

When some different models in the same phenomena exist, how should we evaluate them? If there is only one type of criterion, e.g. describing reality, we wouldn't be bothered by choosing the best model. However, building models includes some other goals, such as explanations, predictions, and goodness-of-fit. The aim of this paper is to examine morphology formation models of ammonites as examples. David Raup builds, for instance, a well-known model which explains shell forms of ammonites. However, his model can't reveal morphology formations of heteromorphs ammonites, e.g. Nipponites and Polyptychoceras. In contrast, Takashi Okamoto provides less famous but more general model that can explain formation patterns for every ammonite including heteromorphs, which the Raup’s model fails to. Furthermore, Okamoto’s model is more refined, and his model reveals the morphology formation process of ammonites. Thus, based on the comparison between Raup's and Okamoto's models, I provide my analysis of the criteria for good models and the philosophies behind the model building strategies.

The limits of equilibrium concepts in evolutionary game theory

Aydin Mohseni (Carnegie Mellon University, United States)

Within the modeling framework of evolutionary game theory, equilibrium concepts adapted from rational choice game theory are employed to identify the probable outcomes of evolutionary processes. Over the last several decades, results have emerged in the literature demonstrating limitations of each of the proposed equilibrium concepts. We present a comprehensive story circumscribing the shortcomings of the primary candidate equilibrium concepts. We argue that these results rely on an implicit notion of evolutionary significance, and propose a novel account of evolutionary significance. We show how this formulation brings clarity to assessments of the success and failure of equilibrium concepts and demonstrate that, even under quite favorable assumptions, each equilibrium concept is simultaneously too weak and too strong.

Reconsidering the game of life: Weak emergence and interventionism

Cory Lewis (University of Toronto, Canada)

The relationship between interventionism and emergence has recently come into question. Some say that interventionism, Woodward's(2003, 2010) proposal for how to understand causal explanation, gives us reason to accept emergent properties (Sober and Shapiro 2007). Others argue the opposite, that interventionism makes emergence impossible (Baumgartner 2010). I try to navigate a path through these arguments, using Bedau's (1997) notion of weak emergence. This shows a way through the tangle, while also casting new light on weak emergence itself. Sober and Shapiro (2007) argue that interventionism provides us reasons to reject Kim's(1997) causal exclusion argument. But Baumgartner(2010) argues that interventionism makes downward-causation, the usual causal interpretation of emergence, impossible in principle. It seems that interventionism tells both for and against emergence. But Bedau's position is specifically addressed to emergence without downward causation, so it provides a way to see the merit in both positions. And interventionism can also offer something to downward causation – specifically, the notion of stability. Bedau caches out the contingency of micro-level processes in emergent phenomena in terms of the requirement that they can “only be simulated”, or that they are explainable only complexly. Woodward's(2010) distinction between stable and unstable causal relations offers a way to cash out the notion of contingency in ontological terms. This causes us to have to reconsider one of Bedau's canonical examples, Conway's Game of Life. Seen in terms of causal stability, we find that it does not have especially emergent dynamics. The micro-dynamics that produce gliders, to take Bedau's example, are extremely widespread across the game's space of possibilities, and are therefore 'stable'. So applying interventionism to weak emergence not only clarifies the debate between Sober, Shapiro, and Baumgartner, it also gives us a new perspective on weak emergence itself.