Online research in philosophy

Levels of reality reflect one kind of complexity, which can be modeled using a specification hierarchy. Levels emerged during the Big Bang, as physical degrees of freedom became increasingly fixed as the expanding universe developed, and new degrees of freedom associated with higher levels opened up locally, requiring new descriptive semantics. History became embodied in higher level entities, which are increasingly individuated, aggregate patterns of lower level entities. Development is an epigenetic trajectory from vaguer to more definite and individuated embodiment, punctuated by the emergence of new integrative levels. It is constrained by being subsumed by lower levels (e.g., physical dynamics) and may be guided by structural attractors as well as by internally stored information (e.g., genes) in the higher levels. I conjecture, on a thermodynamic basis, that the number of levels that become manifest in an expanding universe depends upon its rate of expansion.

There is the popular notion according to which the world is built up in a hierarchical order, such that combining entities from the lower level results in entities of the next higher level, and so on. It seems beyond doubt in this view that the entities at the lowest level are some subatomic particles, to be followed at the next levels by atoms, molecules, biological organs and organisms including humans, and eventually societies. Accordingly, a scientific discipline is assigned to each level, resulting in a disciplinary hierarchy that starts with physics and goes via chemistry, biology, and psychology to sociology. This popular notion has its merits as it assures us that both the world and our scientific knowledge are perfectly ordered in a harmonious but hierarchical manner. It provides philosophical food to discuss the interfaces between the ontological levels or disciplines in terms of reduction, emergence, supervenience, and so on. And it appeals to some philosophers who are interested in science but unable to read the about two million scientific publications per year, because it allows them to focus on the handful of publications in what is supposed to be the fundamental level of Everything. The hierarchical picture became popular in the 19th century just when most of our scientific disciplines emerged in a process of horizontal diversification, when each discipline carved out and established its own specific subject matter, methodology, theories, and problems and rejected just the idea of the hierarchical dependencies between the disciplines (Stichweh 1984). Despite its anachronism at the time of its popularization, the hierarchical picture was appealing to all those who felt lost in the exploding fields of science and who were yearning for the good old days in which a simple metaphysical scheme could provide order to the entire world. It is more than likely that the hierarchical picture is appealing still nowadays for the same reasons. It would not be worthwhile to discuss the anachronistic hierarchical picture, if it had not such a great appeal to many philosophers.1 In this paper I discuss only one particular problem of the hierarchical picture, the lack of matter or stuffs2 in the ontological hierarchy, which actually consists in a series of structures or forms..

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.

This book is the apologia of a frustrated reductionist. The frustration derives from Rosenberg's clear perception that the project of physicalist reduction, the reduction of all the sciences of complex objects to physics, is impossible, at least, as he often says, for beings hampered by our limited cognitive and computational abilities. The reductionism that survives this realisation is purely metaphysical. It is the firm commitment to the view that ultimately whatever happens happens because of the universally lawlike behavior of the physical particles of which everything is composed. What holds these theses together is supervenience. The physical correlate of a higher level property or kind is typically massively disjunctive. Thus although the intrinsic properties of a complex thing are fully determined by the properties of the physical particles of which they are composed, the physical property necessary and sufficient to determine such a higher level property is too complex and disjunctive for our feeble minds to grasp. The underlying physical heterogeneity of the properties or kinds we distinguish at higher structural levels is such as to make it vanishingly unlikely that these will enter into the kinds of universal laws characteristic of physics or chemistry.

I distinguish Nature from the World. I also distinguish development from evolution. Development is progressive change and can be modeled as part of Nature, using a specification hierarchy. I have proposed a ‘canonical developmental trajectory’ of dissipative structures with the stages defined thermodynamically and informationally. I consider some thermodynamic aspects of the Big Bang, leading to a proposal for reviving final cause. This model imposes a ‘hylozooic’ kind of interpretation upon Nature, as all emergent features at higher levels would have been vaguely and episodically present primitively in the lower integrative levels, and were stabilized materially with the developmental emergence of new levels. The specification hierarchy’s form is that of a tree, with its trunk in its lowest level, and so this hierarchy is appropriate for modeling an expanding system like the Universe. It is consistent with this model of differentiation during Big Bang development to view emerging branch tips as having been entrained by multiple finalities because of the top-down integration of the various levels of organization by the higher levels.

We examine some assumptions about the nature of ‘levels of reality’ in the light of examples drawn from physics. Three central assumptions of the standard view of such levels (for instance, Oppenheim and Putnam 1958) are (i) that levels are populated by entities of varying complexity, (ii) that there is a unique hierarchy of levels, ranging from the very small to the very large, and (iii) that the inhabitants of adjacent levels are related by the parthood relation. Using examples from physics, we argue that it is more natural to view the inhabitants of levels as the behaviors of entities, rather than entities themselves. This suggests an account of reduction between levels, according to which one behavior reduces to another if the two are related by an appropriate limit relation. By considering cases where such inter-level reduction fails, we show that the hierarchy of behaviors differs in several respects from the standard hierarchy of entities. In particular, while on the standard view, lower-level entities are ‘micro’ parts of higher-level entities, on our view, a system’s macro-level behavior can be seen as a (‘non-spatial’) part of its micro-level behavior. We argue that this second hierarchy is not really in conflict with the standard view and that it better suits examples of explanation in science.

Mechanisms in a theory are defined here as bits of theory about entities at a different level (e.g., individuals) than the main entities being theorized about (e.g., groups), which serve to make the higher-level theory more supple, more accurate, or more general. The criterion for whether it is worthwhile to theorize at lower levels is whether it makes the theory at the higher levels better, not whether lower-level theorizing is philosophically necessary. The higher-level theory can be made better by mechanisms known to be inadequate in the discipline dealing with the lower level. Conditions for the usefulness of lower-level theorizing are proposed, with many examples from various social and physical sciences.

The target paper of Dr. Feinberg is a testimony to an admirable scholarship and deep thoughtfulness. This paper develops a general theoretical framework of nested hierarchy in the brain that allows production of mind with consciousness. The difference between non-nested and nested hierarchies is the following. In a non-nested hierarchy the entities at higher levels of the hierarchy are physically independent from the entities at lower levels and there is strong constraint of higher upon lower levels. In a nested hierarchy, higher levels are physically composed of lower levels, and there is no central control of the system resulting in weak constraint of higher upon lower levels.

Most philosophical accounts of causation take causal relations to obtain between individuals and events in virtue of nomological relations between properties of these individuals and events. Such views fail to take into account the consequences of the fact that in general the properties of individuals and events will depend upon mechanisms that realize those properties. In this paper I attempt to rectify this failure, and in so doing to provide an account of the causal relevance of higher-level properties. I do this by critiquing one prominent model of higher-level properties—Kim’s functional model of reduction—and contrasting it with a mechanistic approach to higher-level properties and causation.

Many philosophers accept a ‘layered’ world‐view according to which the facts about the higher ontological levels supervene on the facts about the lower levels. Advocates of such views often have in mind a version of atomism, according to which there is a fundamental level of indivisible objects known as simples or atoms upon whose spatiotemporal locations and intrinsic properties everything at the higher levels supervenes.1 Some, however, accept the possibility of ‘gunk’ worlds in which there are parts ‘all the way down’ such that there are no simples and insofar as composite objects exist these are composed of smaller objects which in turn are composed of smaller objects, and so on. It may nonetheless still be claimed that the facts about each ontological level supervene on the facts about the lower levels.