The conference was a success, both from a philosophical and from an interdisciplinary perspective. As the title of the conference - Mental Causation: Does Mind Matter? - indicates, the focus of the talks has been the question whether, and if yes, how, mental states of human beings, like beliefs, desires, intentions, etc. can causally influence the course of the (physical) body of their bearers. When investigated from an empirical, i. e. neurophysiological, neurobiological or neuropsychological, viewpoint, this question becomes: What causal pathways are there, between the neural correlates of mental states (if any can be pinned down at all), and those neural events that initiate a certain motor output? When investigated from a philosophical viewpoint, it becomes: How can higher-level properties, i.e. properties that are realized by more basic properties, be causally relevant for the occurrence of a given effect, given that there will always be lower-level properties available to 'screen them off', i. e. to make them look causally redundant.
Partially, the important take-home message from the interdisciplinary discussion, especially during the round table session on the final day, was negative, in the sense that the discussion between the participants showed what is, currently at least, difficult or impossible about interdisciplinary discourse. Transferring typically philosophical categories such as event, causation, neural correlate to the empirical sciences is at least problematic, if not misleading. Contrary to the way philosophers usually talk, there is no clearly delimitable neural correlate of a given mental state, and this is one of the reasons why it is nearly impossible to apply philosophical theories of the mind-body relationship (reductionism, property-dualism, event-identity etc.) one-to-one to empirical theories (Vogeley and H. Walter). Equally well, the philosophical notion of causation as a two place relation between concrete events apparently fails to capture the way empirical scientists conceive of the mechanisms of psychophysical causation (Bickle).
From a purely philosophical point of view, the two most important conclusions were the following: First, the possibility of higher-level causation is a general philosophical problem that arises in various areas of philosophy alike (philosophy of science, philosophy of mind) and hence can't originate in a confusion of a certain type of prejudiced philosophical theory about the mind-body relationship (Beckermann, Crane). Second, epiphenomenalism, a position that has long been considered a dead end seems to be back in the ballpark again, if only as the final resort of the despaired. Epiphenomenalism is the philosophical position that holds that higher-level causation is impossible: higher-level properties and states, including mental ones, do not contribute causally to the course of the physical world, they are causally otiose.
While epiphenomenalists used to earn incredulous stares only, more and more people seem to be willing to accept it (Heckmann, Staudacher, S. Walter). They are still vehemently opposed by others (Beckermann, Kim), but several of the talks presented at the ZiF conference revealed that they have an argumentative point in their favour: the problem of 'causal drainage' (Kim), i.e. the possibility that causation only occurs at the most basic level of reality (causality 'draining away' all the way down to the level of fundamental physics), is a problem that has so far not been solved, neither philosophically nor empirically. It seems fair to say that none of the attempts to formulate a theory of higher-level causation, thereby providing a solution to the problem of causal drainage (Antony, Buekens, de Muijnck, Kim), was ultimately compelling. As long as such an account is missing, epiphenomenalists can sustain their initially implausible position by an inference to the best explanation: maybe the explanation for why we haven't found a successful theory of higher-level causation is that there isn't higher-level causation to begin with. Mind, to answer the question in the title of the conference, may simply not matter.