Emergent properties theory

The development of theoretical chemistry ceased at about 1930. The last significant contributions came from the first of the modern theoretical physicists, who have long since lost interest in the subject. It is not uncommon today, to hear prominent chemists explain how chemistry is an experimental science, adequately practiced without any need of quantum mechanics or the theories of relativity. Chemical thermodynamics is routinely rehashed in the terminology and concepts of the late nineteenth century. The formulation of chemical reaction and kinetic theories take scant account of statistical mechanics and non-equilibrium thermodynamics. Theories of molecular structure are entirely classical and molecular cohesion is commonly analyzed in terms of isolated bonds. Holistic effects and emergent properties that could... 

Primas uses this argument to introduce the notion of contextual ontology, which refers to emergent properties arising from hidden features of the independent reality. This permits a clear view of the relation between contextual and fundamental theories, and also a generalization that is relevant for philosophy of science at large ... 

Apart from detail, reformulation of quantum theory to be consistent with chemical behaviour, requires the recognition of molecular structure. In this spirit, it may be introduced as an essential assumption, or emergent property, without immediate expectation of retrieving the concept from first principles. Medium-sized molecules, especially in condensed phases, are assumed to have a characteristic three-dimensional distribution of atoms, which defines a semi-rigid, flexible molecular frame. The forces between the atoms are of quantum-mechanical origin, but on a macro scale, are best described in terms of classical forces. 

The unity of science appears indisputable. The way in which all facts hang together implies the reductionist principle. Failure of constructionism denies the priority of any branch of science over any other because of the unpredictability of emergent properties. The single discipline, normally not considered a science, but fundamental to all scientific facts, is mathematics, ft now appears that science, at all levels, is intimately entangled with number theory. 

The remedy is not to attempt the reduction of chemistry to the one-particle solutions of quantum physics, without taking the emergent properties of chemical systems into account. Chemical reactions occur in crowded environments where the presence of matter in molar quantities is not without effect on the behaviour of the quantum objects that mediate the interactions. It is only against this background that quantum theory can begin to make a useful contribution to the understanding of chemical systems. 

In 1926 there emerged the theory known asc/uantum mechanics developed, in the form most useful to chemists, by Erwin Schrddinger (of the University of Zurich). He worked out mathematical expressions to describe the motion of an electron in terms of its energy. These mathematical expressions are called wave equations, since they are based upon the cjncept that electrons show properties not only of particles but also of waves. 

The new model of accidents introduced in part II of this book incorporates the basic systems theory idea of hierarchical levels, where constraints or lack of constraints at the higher levels control or allow lower-level behavior. Safety is treated as an emergent property at each of these levels. Safety depends on the enforcement of constraints on the behavior of the components in the system, including constraints on their potential interactions. Safety in the batch chemical reactor in the previous chapter, for example, depends on the enforcement of a constraint on the relationship between the state of the catalyst valve and the water valve. 

In systems theory, emergent properties, such as safety, arise from the interactions among the system components. The emergent properties are controlled by imposing constraints on the behavior of and interactions among the components. Safety then becomes a control problem where the goal of the control is to enforce the safety constraints. Accidents result from inadequate control or enforcement of safety-related constraints on the development, design, and operation of the system. 

Another holistic aspect of system theory describes emei ent properties. Properties that result from the interaction of system components, properties that are not those of the components themselves, are referred to as emergent properties. 

It is not unexpected that problems often occur in the fundamental analysis of emergent properties. Maybe the prudent response of the chemist should then be a critical reexamination of those assumptions that underpin the partially successful theory. In any theory, there is a reductionist limit, beyond which there are no data to guide the recognition of more fundamental principles. In the theory of matter, this limit occurs in the vacuum, or sub-ether [2], seen as the primaeval form of matter, continuously spread across the endless void. On deformation of this featureless cosmos, ponderable matter emerges from the void as elementary distortions, which are perpetually dispersed, except in a closed system. We propose such a structure as... 

Holism is a nonreductionist strategy for generating explanatory principles of whole systems. Attention is focused on the emergent properties of the whole rather than on the reductionist behavior of the isolated parts. The approach typically involves and generates empathetic, experiential, and intuitive understanding, not merely analytic understanding. Holism theory is the foundation for systems theory. 

This chapter introduces tools from statistical mechanics that are useful for analyzing the behavior of static and slowly driven granular media. (For fast dynamics, refer to the previous chapter on Kinetic Theory by Jenkins.) These tools encompass techniques used to predict emergent properties from microscopic laws, which are the analogs of calculations in equilibrium statistical mechanics based on the concept of statistical ensembles and stochastic dynamics. Included, for example, are the Edwards approach to static granular media, and coarse-grained models of... 

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