As human beings, we are inclined to believe that the conscious exercise of our own capacities makes us the source of what happens in society. But is this just an anthropocentric illusion? Can human beings really be regarded as agents with a causal impact on our social world, and if so, how can we justify such a claim? What is it about human beings that gives us the power to act, and how does our sense that we are making decisions relate to how our actions are really determined?

This chapter will argue that we human individuals do indeed have causal powers of our own, and that those causal powers are emergent properties. Thus, in explaining the powers of human individuals – their capability for exercising agency – we must consider the questions identified in chapter 4: what are the parts, and how are they related, that make up human individuals? How does this sort of structure lead to the powers that they possess? And how is this sort of structure brought about and sustained? We cannot give an ontologically coherent response to these questions without recognising the biological nature of human beings. As a work of social theory this book will neglect most of the physiological details, but we cannot ignore the biological basis of human capacities entirely if we are to construct an adequate understanding of human social functioning. Nor, however, can we neglect the fact that human behaviour is causally influenced by external factors.