 It is one thing to delineate the contours of the notion of emergence, another to argue that emergent phenomena actually exist. A wide variety of phenomena have been held to be emergent. Apart from consciousness, various chemical and biological phenomena have been held to be emergent. Broad is not willing to rule out a physicalistic reduction of chemistry and biology to physics: chemical and biological phenomena might, he believes, very well be reducible to complex microphysical processes. In his opinion, however, consciousness is a different matter. We will turn to consciousness in a moment. When it comes to biology and chemistry he declares that he does not see any “a priori impossibility in a mechanistic biology or chemistry” (1925, p. 72). He stresses that it is in practice enormously difficult to know whether, say, a certain biological feature such as nutrition is emergent or not. It is evident from what Broad says that he recognises that the Emergentist stance has its dangers in that it tends to encourage acceptance of laws and properties as ultimate and irreducible. There is a danger in this because, as he notes, reductive explanations have proved remarkably successful in the past, and there is the possibility that what we take to be an emergent phenomenon is in fact reducible.