According to conventional wisdom, local gauge symmetry is not a symmetry of nature, but an artifact of how our theories represent nature. But a study of the so-called theta-vacuum appears to refute this view. The ground state of a quantized non-Abelian Yang-Mills gauge theory is characterized by a real-valued, dimensionless parameter theta—a fundamental new constant of nature. The structure of this vacuum state is often said to arise from a degeneracy of the vacuum of the corresponding classical theory, which degeneracy (...) allegedly arises from the fact that “large” (but not “small”) local gauge transformations connect physically distinct states of zero field energy. If that is right, then some local gauge transformations do generate empirical symmetries. In defending conventional wisdom against this challenge I hope to clarify the meaning of empirical symmetry while deepening our understanding of gauge transformations. I distinguish empirical from theoretical symmetries. Using Galileo’s ship and Faraday’s cube as illustrations, I say when an empirical symmetry is implied by a theoretical symmetry. I explain how the theta-vacuum arises, and how “large” gauge transformations differ from “small” ones. I then present two analogies from elementary quantum mechanics. By applying my analysis of the relation between empirical and theoretical symmetries, I show which analogy faithfully portrays the character of the vacuum state of a classical non-Abelian Yang-Mills gauge theory. The upshot is that “large” as well as “small” gauge transformations are purely formal symmetries of non-Abelian Yang-Mills gauge theories, whether classical or quantized. It is still worth distinguishing between these kinds of symmetries. An analysis of gauge within the constrained-Hamiltonian formalism yields the result that “large” gauge transformations should not be classified as gauge transformations; indeed, nor should “global” gauge transformations. In a theory in which boundary conditions are modeled dynamically, “global” gauge transformations may be associated with physical symmetries, corresponding to translations of these extra dynamical variables. Such translations are symmetries if and only if charge is conserved. But it is hard to argue that these symmetries are empirical, and in any case they do not correspond to any constant phase change in a quantum state. (shrink)

To explain phenomenon R by showing how mechanism M yields output R each time it is triggered by circumstances C, is to give a causal explanation of R. This paper analyses what mechanistic analysis can contribute to our understanding of causation in general and of downward causation in particular. It is first shown, against Glennan, that the concept of causation cannot be reduced to that of mechanism. Second it is shown, against Craver and Bechtel, that mechanistic explanation allows us to (...) make sense of causal processes that cut across levels, either in bottom-up direction where a change in a part of a system causes a change in the whole, or in downward direction where a change at the level of the system causes a change at the level of its parts. I suggest construing a decision's influence on molecules in muscle cells as a global constraint. Microscopic laws determine the detailed evolution of muscle cells and glucose molecules, but this evolution is constrained by the fact that it must be compatible with the action caused by the decision. (shrink)

The purpose of the article is to analyze the concept of contextual emergence as well as its selected applications in philosophy of mind and cognitive science. In the first section the author presents the general assumptions of the emergentist model of reality. He stresses that the concept of emergence can be applied to the description of various levels of organization of nature: one of these levels is that of mental-cognitive processes, analyzed within the fields of philosophy of mind and cognitive (...) science. In the subsequent sections, he introduces the definitions of contextual emergence and systemic causation and he points to their selected applications to mentalcognitive systems. In the concluding part, he presents the ideas of Gerald Edelman and Michael Gazzaniga on the role of contextual explanations as well as the concepts of emergence in the philosophy of biology and cognitive neuroscience. He also indicates the possibility of incorporating the concept of contextual emergence into active externalism and the extended cognition theory. (shrink)

Physicalism is usually understood as the claim that every empirical entity is or is determined by physical entities. The claim is however imprecise until it is clarified what are the physical entities in question. A sceptical argument in the form of a dilemma tries to show that this problem of formulation of physicalism cannot be adequately met. If we understand physical entities as the entities introduced by current physics, the resulting claim becomes most probably false. If we instead understand physical (...) entities as those entities introduced by some future ideal physics, the claim then becomes indeterminate in content. Both horns seem equally bad. In the first part of the paper, I survey the strengths and weaknesses of different proposed solutions to this problem of formulation. In the second part, I lay out a new formulation of physicalism, partly based on a mereological principle, which overcomes the dilemma, and argue that it is a correct formulation of physicalism to the extent that it rules out clear antiphysicalist scenarios and is compatible with clear physicalist scenarios. (shrink)

This paper explores the fundamental ideas that have motivated the idea of emergence and the movement of emergentism. The concept of reduction, which lies at the heart of the emergence idea is explicated, and it is shown how the thesis that emergent properties are irreducible gives a unified account of emergence. The paper goes on to discuss two fundamental unresolved issues for emergentism. The first is that of giving a “positive” characterization of emergence; the second is to give a coherent (...) explanation of how “downward” causation, a central component of emergentism, is able to avoid the problem of overdetermination. (shrink)

Here I offer a precise analysis of what it takes for a property to count as emergent. The features widely considered crucial to emergence include novelty, unpredictability, supervenience, relationality, and downward causal influence. By acknowledging each of these distinctive features, the definition provided below captures an important sense in which the whole can be more than the sum of its parts.

The evolutionary emergence of biological processes in organisms with inner, qualitative aspects has not been explained in any sufficient way by neurobiology, nor by the traditional neo-Darwinian paradigm — natural selection would appear to work just as well on insentient zombies (with the right behavioral input-output relations) as on real sentient animals. In consciousness studies one talks about the ‘hard problem’ of qualia. In this paper I sketch a set of principles about sign action, causality and emergent evolution. On the (...) basis of these principles, I characterize a concept of cause that would allow for a naturalistic explanation of the origin of consciousness. The suggested account of causation also turns the ‘hard problem’ of qualia into the easier problem of relating experimental biology to experiential biology. (shrink)

Emotion is conscious experience. It is the affective aspect of consciousness. Emotion arises from sensory stimulation and is typically accompanied by physiological and behavioral changes in the body. Hence an emotion is a complex reaction pattern consisting of three components: a physiological component, a behavioral component, and an experiential (conscious) component. The reactions making up an emotion determine what the emotion will be recognized as. Three processes are involved in generating an emotion: (1) identification of the emotional significance of a (...) sensory stimulus, (2) production of an affective state (emotion), and (3) regulation of the affective state. Two opposing systems in the brain (the reward and punishment systems) establish an affective value or valence (stimulus-reinforcement association) for sensory stimulation. This is process (1), the first step in the generation of an emotion. Development of stimulus-reinforcement associations (affective valence) serves as the basis for emotion expression (process 2), conditioned emotion learning acquisition and expression, memory consolidation, reinforcement-expectations, decision-making, coping responses, and social behavior. The amygdala is critical for the representation of stimulus-reinforcement associations (both reward and punishment-based) for these functions. Three distinct and separate architectural and functional areas of the prefrontal cortex (dorsolateral prefrontal cortex, orbitofrontal cortex, anterior cingulate cortex) are involved in the regulation of emotion (process 3). The regulation of emotion by the prefrontal cortex consists of a positive feedback interaction between the prefrontal cortex and the inferior parietal cortex resulting in the nonlinear emergence of emotion. This positive feedback and nonlinear emergence represents a type of working memory (focal attention) by which perception is reorganized and rerepresented, becoming explicit, functional, and conscious. The explicit emotion states arising may be involved in the production of voluntary new or novel intentional (adaptive) behavior, especially social behavior. (shrink)