Emergence in Chemistry: Chemistry as the Embodiment of Emergence

The main aim of the paper is to reinforce the notion that emergence is a basic characteristic of the molecular sciences in general and chemistry in particular. Although this point is well accepted, even in the primary reference on emergence, the keyword emergence is rarely utilized by chemists and molecular biologists and chemistry textbooks for undergraduates. The possible reasons for this situation are discussed. The paper first re-introduces the concept of emergence based on very simple geometrical forms; and considers some simple chemical examples among low and high molecular weight compounds. On the basis of these chemical examples, a few interesting philosophical issues inherent to the field of emergence are discussed – again making the point that such examples, given their clarity and simplicity, permit one to better understand the complex philosophical issues. Thus, the question of predictability is discussed, namely whether and to what extent can emergent properties be predicted on the basis of the component’s properties; or the question of the explicability (a top down process). The relation between reductionism and emergentism is also discussed as well as the notion of downward causality and double causality (macrodeterminism); namely the question whether and to what extent the emergent properties of the higher hierarchic level affect the properties of the lower level components. Finally, the question is analyzed, whether life can be considered as an emergent property. More generally, the final point is made, that the re-introduction of the notion of emergence in chemistry, and in particular in the teaching, may bring about a deeper understanding of the meaning of chemical complexity and may bring chemistry closer to the humanistic areas of philosophy and epistemology. This revised version was published online in July 2006 with corrections to the Cover Date.