Computational modeling of the brain holds great promise as a bridge from brain to behavior. To fulfill this promise, however, it is not enough for models to be 'biologically plausible': models must be structurally accurate. Here, we analyze what this entails for so-called psychobiological models, models that address behavior as well as brain function in some detail. Structural accuracy may be supported by (1) a model's a priori plausibility, which comes from a reliance on evidence-based assumptions, (2) fitting existing data, (...) and (3) the derivation of new predictions. All three sources of support require modelers to be explicit about the ontology of the model, and require the existence of data constraining the modeling. For situations in which such data are only sparsely available, we suggest a new approach. If several models are constructed that together form a hierarchy of models, higher-level models can be constrained by lower-level models, and low-level models can be constrained by behavioral features of the higher-level models. Modeling the same substrate at different levels of representation, as proposed here, thus has benefits that exceed the merits of each model in the hierarchy on its own. (shrink)
The traditional use of ergodic theory in the foundations of equilibrium statistical mechanics is that it provides a link between thermodynamic observables and microcanonical probabilities. First of all, the ergodic theorem demonstrates the equality of microcanonical phase averages and infinite time averages (albeit for a special class of systems, and up to a measure zero set of exceptions). Secondly, one argues that actual measurements of thermodynamic quantities yield time averaged quantities, since measurements take a long time. The combination of these (...) two points is held to be an explanation why calculating microcanonical phase averages is a successful algorithm for predicting the values of thermodynamic observables. It is also well-known that this account is problematic.
This survey intends to show that ergodic theory nevertheless may have important roles to play, and it explores three other uses of ergodic theory. Particular attention is paid, firstly, to the relevance of specific interpretations of probability, and secondly, to the way in which the concern with systems in thermal equilibrium is translated into probabilistic language. With respect to the latter point, it is argued that equilibrium should not be represented as a stationary probability distribution as is standardly done; instead, a weaker definition is presented. (shrink)
In the usual procedure of deriving equilibrium thermodynamics from classical statistical mechanics, Gibbsian fine-grained entropy is taken as the analogue of thermodynamical entropy. However, it is well known that the fine-grained entropy remains constant under the Hamiltonian flow. In this paper it is argued that we need not search for alternatives for fine-grained entropy, nor do we have to reject Hamiltonian dynamics, in order to solve the problem of the constancy of fine-grained entropy and, more generally, to account for (...) the non-equilibrium part of the laws of thermodynamics. Rather, we have to weaken the requirement that equilibrium be identified with a stationary probability distribution. (shrink)
The legitimacy of the dominant intensive meat production system with respect to the issue of animal welfare is increasingly being questioned by stakeholders across the meat supply chain. The current meat supply is highly undifferentiated, catering only for the extremes of morality concerns (i.e., conventional vs. organic meat products). However, a latent need for compromise products has been identified. That is, consumer differences exist regarding the trade-offs they make between different aspects associated with meat consumption. The heterogeneity in consumer demand (...) could function as a starting point for market segmentation, targeting and positioning regarding animal welfare concepts that are differentiated in terms of animal welfare and price levels. Despite this, stakeholders in the meat supply chain seem to be trapped in the dominant business model focused on low cost prices. This paper aims to identify conflicting interests that stakeholders in the meat supply chain experience in order to increase understanding of why heterogeneous consumer preferences are not met by a more differentiated supply of meat products produced at different levels of animal welfare standards. In addition, characteristics of the supply chain that contribute to the existence of high exit barriers and difficulty to shift to more animal-friendly production systems are identified. Following the analysis of conflicting interests among stakeholders and factors that contribute to difficulty to transform the existing dominant regime, different routes are discussed that may help and motivate stakeholders to overcome these barriers and stimulate the creation of new markets. (shrink)
