Metaphysics, it is often said, asks what things there are, and what things are like. But there is also an alternative conception, historically associated with Aristotle, and recently revived in the work of Kit Fine and others, according to which there is another central question of metaphysics: What facts depend on, are grounded by, what other facts? The first conception of metaphysics is adequate only given a view of reality as a mere collection of facts, the second takes into account that reality has structure: some facts obtain because others do.
Now, because and cognate terms often describe causal structures, such as when we say that the glass broke because it was dropped. But in the cases of most interest to metaphysics, because tracks non-causal relations, e.g. when we ask whether moral facts obtain because of facts concerning mental events, and whether the latter obtain because of certain physical facts; neither question plausibly concerns causality. Call this other notion of because the metaphysical because, and the relation it denotes (metaphysical) grounding.
Even though the picture of reality as structured in this way seems very plausible, and seems to appear in philosophical discourse no later than Plato's Euthyphro and Aristotle's theory of the four causes, the theory of metaphysical grounding is in a very poor state as compared to notions similarly central to metaphysics, like existence, generality, necessity and possibility -- largely because during the 20th century, it was almost entirely neglected. This can be attributed in part to the lingering anti-metaphysical stance of the logical positivists, and in part to the special difficulty of the concept of ground, which has made it appear to many to resist systematic theorizing. Things changed only in 2001, with Kit Fine's influential paper The Question of Realism; since then, a highly productive debate on grounding has developed, in which some first steps towards a developed theory of grounding have already been made.
This project is based on the conviction that the metaphysical because is as central to metaphysics as concepts like existence, identity, and necessity. And while our theoretical grasp of the latter has improved immensely over the last century, not least through the methods of formal logic and semantics, our theory of grounding is much less developed. The main aim of my project, accordingly, is to help fill this deficit. To that end, I shall investigate in systematic fashion the most important structural properties of grounding and in particular its interaction with the other mentioned core concepts of metaphysics, especially those of existence and generality. This inquiry will be informed by the formal methods of logic and semantics, while at the same time keeping in focus the genuinely philosophical questions which those methods are supposed to help us answer.