ABSTRACT
According to ‘strong emergence’ – which is the type of emergentism that I shall be concerned with throughout this chapter – certain properties emerge from, they arise out of, more fundamental physical properties, and yet emergent properties are not merely distinct from physical properties, but are novel, ‘something over and above’ the properties from which they arise. Hence, for example, those who are committed to the existence of emergent mental properties hold that mental properties emerge from more fundamental physical properties and yet are something over and above them. How exactly to understand ‘strong emergence’, beyond its negative characteristic of being incompatible with the physicalist claim that all non-physical properties are ‘nothing over and above’ physical properties is a much-disputed issue, which I do not have the space to explore here. That said, to capture a ‘strong emergence’ worthy of the name, emergent properties must exist in as robust a sense as the physical properties from which they emerge. Moreover, emergent entities must have full-blooded, independent causal powers that exist over and above the causal powers of the physical entities from which they emerge and which can, given a commitment to downward causation, affect physical entities. In virtue of the combination of its commitment to the claims that emergent properties are distinct from physical properties and that emergent properties are causally relevant in the physical domain, the principle of the causal closure of the physical domain presents a problem for emergence. Indeed, the causal closure argument – one essential premise of which is the causal closure principle – is the central argument against emergence in contemporary discussions of the ontological status of emergent entities.
