Brian McLaughlin is a professor of philosophy at Rutgers. He works on the mind-body problem, supervenience, emergence, and the nature of colors. He is also interested in the philosophy of science, notably cognitive science and computational psychology. He is an editor of The Oxford Handbook of Philosophy Of Mind, Contemporary Debates in Philosophy of Mind, and a landmark 1991 essay on philosophers that he dubbed the "British Emergentists" in Emergence or Reduction?: Essays on the Prospects of Nonreductive Physicalism. McLaughlin's emergentists include John Stuart Mill, George Henry Lewes, C. Lloyd Morgan, Samuel Alexander, and C. D. Broad. McLaughlin developed an "idealized" version of British Emergentism, synthesizing what most had in common into a coherent and representative picture. He says:
British Emergentism maintains that everything is made of matter: There are, for example, no Cartesian souls, or entelechies, vital elan, or the like. And it holds that matter is grainy, rather than continuous; indeed, that it bottoms-out into elementary material particles, atoms or more fundamental particles...Moreover, on its view, nothing happens, no change occurs, without some motion of elementary particles. And all motion is to the beat of the laws of mechanics. According to British Emergentism, there is a hierarchy of levels of organizational complexity of material particles that includes, in ascending order, the strictly physical, the chemical, the biological, and the psychological level. There are certain kinds of material substances specific to each level. And the kinds of each level are wholly composed of kinds of lower levels, ultimately of kinds of elementary material particles. Moreover, there are certain properties specific to the kinds of substances of a given level. These are the "special properties" of matter... What is especially striking about British Emergentism, however, is its view about the causal structure of reality. I turn to that view in the following two paragraphs. British Emergentism maintains that some special science kinds from each special science can be wholly composed of types of structures of material particles that endow the kinds in question with fundamental causal powers. Subtleties aside, the powers in question "emerge" from the types of structures in question. Chemical elements, in virtue of their minute internal structures, have the power to bond with certain others. Certain biological organisms, in virtue of their minute internal structure, have the powers to breathe, to digest food, and to reproduce (Broad 1925, pp. 78 —81). And certain kinds of organisms, in virtue of the minute internal structures of their nervous systems, have "the power of cognizing, the power of being affected by past experiences, the power of association, and so on" (Broad 1925, p. 436). These powers emerge from the types of structures in question. The property of having a certain type of structure will thus endow a special science kind with emergent causal powers. Such a structure will have an emergent causal power as a matter of law, but the law will be not be "reducible to" or "derivative from" laws governing lower levels of complexity and any boundary conditions involving the arrangements of particles. The laws that attribute such powers to the types of structures in question are "emergent laws". These laws "emerge" from the laws governing lower levels of complexity and boundary conditions involving the arrangements of particles, and so are in no sense derivative from them. Now, the exercise of the causal powers in question will involve the production of movements of various kinds. Indeed, Emergentism maintains that special kinds, in virtue of possessing certain types of minute internal structures, have the power to influence motion. And here is the striking point: They endow the kinds with the power to influence motion in ways unanticipated by laws governing less complex kinds and conditions concerning the arrangements of particles. Emergentism is committed to the nomological possibility of what has been called "downward causation".McLaughlin's work is cited in modern attempts to defend an emergent dualism, downward causation, and a nonreductive physicalism in the face of criticism from Jaegwon Kim. For McLaughlin, the question becomes whether what the British Emergentists were looking for is "nomologically" possible in terms of modern physics, which departs from the nineteenth-century view of strict causality, what Kim calls "causal closure." McLaughlin points out that Broad's The Mind and Its Place In Nature appeared just as quantum mechanics was being formulated in the late 1920's. He asks whether quantum mechanics or relativity offer any new ways that support downward causation, but he remains very skeptical.
David Bohm's (1989) interpretation of the formalism of quantum mechanics understands the quantum potential in a way that seems to involve downward causation...And Einstein's field equations, of general relativity may count as involving downward causation. Of course, downward causation from the psychological, biological, or chemical level is another matter. That is enormously implausible. There is overwhelming reason to reject that idea and the existence of configurational chemical, vital, or psychological forces. Or so I argue below. Let us pause for a moment to ask what the Emergentist notion of emergent causal powers and laws at the chemical, biological, and psychological levels would mean in the context of nonrelativistic quantum mechanics. Schrodinger's equation is the fundamental law of nonrelativistic quantum mechanics. It governs the evolution of systems through time. It tells us that the temporal evolution of a state vector ψ is determined by H ψ = ih δψ/δt, where H is the Hamiltonian operator and h is Planck's constant divided by 2π. Now, to employ the equation, one must independently determine the Hamiltonian. The Hamiltonian concerns energy, rather than forces. (Quantum mechanics could, however, be recast in terms of forces, it is just that the mathematics would be considerably more complex; scalars are, of course, easier to compute with than vectors.) But on the Emergentist view in question there would be kinds of energies specific to types of structures of particles that compose certain chemical, biological, and psychological kinds. Hereafter, I will, however, focus on the notion of configurational forces, rather than energies and the Hamiltonian. Quantum mechanics was not developed until just after the publication of The Mind and Its Place in Nature; and this was, as I mentioned, the last major work in the Emergentist tradition. Alexander, Morgan, and Broad lived to see the advent of quantum mechanics. But when they were writing in the Emergentist tradition, they knew nothing of Schrodinger's equation or the like. It is, I contend, no coincidence that the last major work in the British Emergentist tradition coincided with the advent of quantum mechanics. Quantum mechanics and the various scientific advances it made possible are arguably what led to British Emergentism's fall. It is not that British Emergentism is logically incompatible with nonrelativistic quantum mechanics. It is not. Schrodinger's equation could be the fundamental equation governing motion in a world with energies that are specific to types of structures of particles that compose certain chemical, biological, and psychological kinds. But, as will become apparent, quantum mechanical explanations of chemical bonding in terms of electro-magneticism, and various advances this made possible in molecular biology and genetics — for example, the discovery of the molecular structure of DNA — make the main doctrines of British emergentism, so far as the chemical and biological are concerned at least, seem enormously implausible.Given the achievements of quantum mechanics and these other scientific theories, there seems not a scintilla of evidence that there are emergent causal powers or laws in the sense in question; there seems not a scintilla of evidence that there are configurational forces; and there seems not a scintilla of evidence that there is downward causation from the psychological, biological, or chemical levels