Online research in philosophy

“Ontological emergence” of inherent high-level properties with causal powers is witnessed nowhere. A non-substantialist conception of emergence works much better. It allows downward causation, provided our concept of causality is transformed accordingly.

Note: this paper will serve as a basis for a book-in-progress. Nearly all accounts of emergence take this to involve both broadly synchronic dependence and (some measure of) ontological and causal autonomy. Beyond this agreement, however, accounts of emergence diverge into a bewildering variety, reflecting that the core notions of dependence and autonomy have multiple, often incompatible interpretations. Luckily for philosophical purposes, however, much of this apparent diversity is superficial---or so I argue in this paper. I start by considering a notorious problematic associated with special science entities---namely, the problem of higher-level causation (a generalization of the problem of mental causation). As we will see, of the various strategies for addressing this problem there are two which plausibly accommodate both the dependence and the ontological and causal autonomy of special science entities.

These strategies in turn suggest two distinct schema for metaphysical emergence, which I call 'Weak' and 'Strong' emergence, respectively. The two schema are similar in that each imposes a (different, specific) condition on the powers of entities taken to be emergent, relative to the powers of their dependence base entities. (Importantly, the notion of “power” at issue here is metaphysically almost entirely neutral, primarily reflecting commitment just to the plausible thesis that what causes an entity may---perhaps only contingently---bring about are associated with how the entity is---that is, with its features.) But the conditions, and accounts, are also crucially different; in particular, one is compatible with physicalism, while the other is not. I go on to consider the main accounts of emergent dependence and emergent autonomy, showing how, properly understood and (in some cases) diambiguated, these aim to instantiate one or the other schema.

I outline reasons for the recent popularity, and lingering suspicion, about 'emergence' by examining three distinct concepts of property emergence, their purposes and associated obligations. In Part 1, I argue 'Strong' emergence is the grail for many emergentists (and physicalists), since it frames what is needed to block the 'Argument from Realization' (AR) which moves from the truth of physicalism to the inefficacy of special science properties. I then distinguish 'Weak' and 'Ontological' emergence, in Part 2, arguing each is a way one may fail to establish the possibility of Strong emergence. But I also show Weak emergence can help the full-blown reductionist and Ontological emergence helps those opposed to physicalism. Lastly, in Part 3, I argue that the Completeness of Physics (CoP) is incompatible with Strong emergence and that rejecting CoP provides hope for the possibility of Strong emergence in a physical world. The result is a notion of Strong emergence offering much to non-reductive physicalism. My final conclusion is that concepts of emergence, when properly understood, have important contributions to make to philosophical debate.

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.

Several theories of emergence will be distinguished. In particular, these are synchronic, diachronic, and weak versions of emergence. While the weaker theories are compatible with property reductionism, synchronic emergentism and strong versions of diachronic emergentism are not. Synchronice mergentism is of particular interest for the discussion of downward causation. For such a theory, a system's property is taken to be emergent if it is irreducible, i.e., if it is not reductively explainable. Furthermore, we have to distinguish two different types of irreducibility with quite different consequences: If, on the one hand, a system's property is irreducible because of the irreducibility of the system's parts' behavior on which the property supervenes, we seem to have a case of "downward causation". This kind of downward causation does not violate the principle of the causal closure of the physical domain. If, on the other hand, a systemic property is irreducible because it is not exhaustively analyzable in terms of its causal role, downward causation is not implied. Rather, it is dubitable how unanalyzable properties might play any causal role at all. Thus, epiphenomenalism seems to be implied. The failure to keep apart the two kinds of irreducibility has muddled recent debate about the emergence of properties considerably.

An innocent form of emergence—what I call "weak emergence"—is now a commonplace in a thriving interdisciplinary nexus of scientific activity—sometimes called the "sciences of complexity"—that include connectionist modelling, non-linear dynamics (popularly known as "chaos" theory), and artificial life.1 After defining it, illustrating it in two contexts, and reviewing the available evidence, I conclude that the scientific and philosophical prospects for weak emergence are bright.

I discuss here a number of different kinds of diachronic emergence, noting that they differ in important ways from synchronic conceptions. I argue that Bedau’s weak emergence has an essentially historical aspect, in that there can be two indistinguishable states, one of which is weakly emergent, the other of which is not. As a consequence, weak emergence is about tokens, not types, of states. I conclude by examining the question of whether the concept of weak emergence is too weak and note that there is at present no unifying account of diachronic and synchronic concepts of emergence.

The idea of a higher level phenomenon having a downward causal influence on a lower level process or entity has taken a variety of forms. In order to discuss the relation between emergence and downward causation, the specific variety of the thesis of downward causation (DC) must be identified. Based on some ontological theses about inter-level relations, types of causation and the possibility of reduction, three versions of DC are distinguished. Of these, the `Strong' form of DC is held to be in conflict with contemporary science; the `Medium' version of DC may for instance describe thoughts constraining neurophysiological states, while the `Weak' form of DC is physically acceptable but may not in practice be a feasible description of the mind/brain or the cell/molecule relation. All forms have their specific problems, but the Medium and the Weak version seems to be most promising.

Weak emergence is the view that a system’s macro properties can be explained by its micro properties but only in an especially complicated way. This paper explains a version of weak emergence based on the notion of explanatory incompressibility and “crawling the causal web.” Then it examines three reasons why weak emergence might be thought to be just in the mind. The first reason is based on contrasting mere epistemological emergence with a form of ontological emergence that involves irreducible downward causation. The second reason is based on the idea that attributions of emergence are always a reflection of our ignorance of non-emergent explanations. The third reason is based on the charge that complex explanations are anthropocentric. Rather than being just in the mind, weak emergence is seen to involve a distinctive kind of complex, macro-pattern in the mind-independent objective micro-causal structure that exists in nature. The paper ends by addressing two further questions. One concerns whether weak emergence applies only or mainly to computer simulations and computational systems. The other concerns the respect in which weak emergence is dynamic rather than static.