Introduction to Special Issue on 'Actual Causation'

An actual cause of some token effect is itself a (distinct) token event (or fact, or state of affairs, ...) that helped to bring about that effect. The notion of an actual cause is different from that of a potential cause – for example a pre-empted backup – which had the capacity to bring about the effect, but which wasn't in fact operative on the occasion in question. Sometimes actual causes are also distinguished from mere background conditions: as when we judge that the struck match was a cause of the fire, while the presence of oxygen was merely part of the relevant background against which the struck match operated. Actual causation is also to be distinguished from type causation: actual causation holds between token events in a particular, concrete scenario; type causation, by contrast, holds between event kinds in scenario kinds. Modern philosophical study of actual causation dates back to Hume (1739-1740), with Mill (1843), Mackie (1965), and Lewis (1973) making field-defining contributions to the subject. While the late twentieth century saw vibrant debate concerning actual causation, there has been a particular surge of interest since the turn of the millennium. One of the key reasons for this has been an increased awareness among philosophers of the availability of formal tools – in particular structural equation models and causal graphs – that can fruitfully be brought to bear in the development of novel solutions to traditional problems confronting attempts to analyze actual causation. Books by Spirtes, Glymour, and Scheines (1993/2000) and Pearl (2000/2009) have been key in bringing these formal tools to the attention of philosophers, with seminal attempts to analyze actual causation using these tools having been made by Pearl (2000, Ch. 10), Halpern and Pearl (2001), Hitchcock (2001), and Woodward (2003, esp. pp. 74-86). Over the subsequent decade or so, this tradition has been greatly enriched by further contributions, including those of Menzies (2004), Halpern and Pearl (2005), Glymour and Wimberly (2007), Hitchcock (2007a), Halpern (2008), and Halpern and Hitchcock (2010, ms.). Though these structural equation approaches to the analysis of actual causation have been highly influential, there continues to be a healthy diversity of alternative approaches that are