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Chapter 11
Modes of Explanation: Complex Phenomena
Sandra Mitchell
Contemporary scientific studies of complexity in biology, social science, and elsewhere have
generated new domains for philosophical thinking about explanation. The complexities and
contingencies of the structures that biologists, psychologists, neuroscientists, and social
scientists explore have major implications for the epistemology of explanation and have
consequently generated new modes of explanation. In large part, this is a result of the
complexity of the structures themselves. The structures I have in mind have multi-level
organization and multi-component causal interactions – think of social insect colonies, the
brain, social institutions. Thus, different causes collaborate, if you like, to generate features
of these complex structures, and they display plasticity in relation to variation in context,
either internal or external. These responsive dynamic structures change in response to other
changes, both internal and external. This responsiveness is a very useful adaptive mechanism
for living in a world that itself is changing.
In addition to the above-mentioned features of complexity, the structures that are
studied by neuroscience, biology, and social science display historical and local dependencies
that contribute to the generation of their behaviors, and these dependencies have to be taken
into account in explaining why we see what we see in the world. Why do we have our current
structures and why do they behave in the way they do?
The emphasis of this chapter is the implications of these features of complex
structures for explanation. In particular, I focus on two implications: the now scientifically
legitimate category of emergent phenomena and emergent properties; and a re-
characterization of the lawful behaviors that explain evolved contingent complex phenomena.
The Science of Emergence
On emergence
Complex structures display emergent properties. We are all familiar with the old
characterization of emergence, attributed to Aristotle (1999), that “the whole is more than the
sum of its parts.” However, for many decades identifying something as an emergent property
was considered to be unscientific. It was widely accepted that science was a reductive
enterprise, and that everything at a higher level of organization should be and could be, in
principle, explained by appeal solely to the properties of the components that constituted that
complex structure.
Much of the contemporary understanding of emergence was developed in the British
emergentist literature from Mill (1843) onwards, through Lloyd Morgan (1923) and Broad
(1925). This characterization of emergentism continues to be endorsed by contemporary
philosophers, particularly those working in the philosophy of mind, such as Jaegwon Kim