# Dissertation Summary

Imagine Norah kindling a fire. She strikes a match, places it on a piece of tinder. The tinder and the logs burst into flames, and a few seconds later the fire is cracking in the fireplace. As you approach it, you can feel its warmth. As you throw your newspaper on it, the fire ignites the pages.

Now also imagine, just as medieval Jewish, Christian, and Muslim philosophers believed, that there is a creator without whom the world would not exist. It’s not just that the world would not have come into being, but that it would not exist right now. Without this creator, there would be no heat of the fire. Indeed, there would be no fire to bring about the heat, no Norah to start the fire, and no matches and tinder to start the fire with. If the creator wants Norah, the matches, the tinder, the fire, and the heat to exist, they do exist; if the creator does not want them to exist, they do not. In this case, you might ask: who did really bring about the fire? Was it Norah, by kindling it? Or was it this creator, by willing it to exist? Or perhaps both?

This cluster of problems is usually called the ‘problem of divine concurrence.’ To put the matter more formally, the question is this: if God causes the world to exist, is he also active in every causal operation in it? Is it meaningful to say in this context that the fire causes the heat? There are, roughly speaking, three ways to answer these questions. First, you might think that if there were such a God, then the fire indeed would not bring about anything, strictly speaking — and in this case, you would be an occasionalist, sharing a view with some medieval Islamic theologians (and later Malebranche). Second, on the contrary, you may opt to argue that if there were such a God who created such a world as we live in, then this God would not contribute to the causal operations of the created world — and in this case, you would be a mere conservationist, sharing a view with only a few medieval thinkers. And third, if you are unsatisfied with either of the previous options, and say that if there were such a God who created such a world as we live in, then both God and things in the world would be causally active in causal operations — then you are a concurrentist, sharing the standard’’ medieval view, that of Thomas Aquinas, John Duns Scotus, William Ockham, and many others.

The dissertation examines the history of this problem as it appeared in three distinct but interconnected debates. After some preliminary matters in Chapter 1 — discussing the problem in more detail and motivating it by reviewing the Latin medieval reception of Arabic occasionalism — the first debate I present concerned whether God is immediately active in every action of a creature, and if yes, what this divine concurring action amounts to (Chapter 2). As was mentioned, most thirteenth-century thinkers thought that the answer to the first question was affirmative. They disagreed, however, on how to understand God’s concurring action, and, consequently, on the response to their mere conservationist contemporaries. Apart from their specific concern, their arguments also shed some light on how to understand the necessary connection between cause and effect in the medieval framework.

The second debate focused on divine concurrence in human volitions (Chapter 3). Although human volitions present special problems with which I cannot deal in detail in this work, interestingly, most arguments against the claim that God concurs with every volition apply to created causes in general. In this debate, the focus expanded to questions about divine foreknowledge, but the main aim remained the same: to account for concurrentism that can avoid falling into occasionalism or mere conservationism.

Occasionalism and the indemonstrability of the causal relation became a central problem in the third debate (Chapter 4). I show that although some fourteenth-century thinkers have been regarded as occasionalists, most of them preserve a clear distinction between proper, sine qua non, and occasional causes. Gabriel Biel, the pre-reformation theologian seems to be the first one to explicitly argue that God is the only genuine causal agent in the world, but even his evaluation is more complicated than it is usually assumed.

I do not wish to claim that these were the only important aspects of the medieval discussion of divine concurrence, or that the authors I consider were the only or most influential ones. Indeed, for instance, as mentioned above, I will mostly disregard the connected and contentious issue whether and how God concurs with voluntary agents, and what this concurrence implies with respect to free will. My focus is what I call ‘natural,’ i.e., non-voluntary causation; not because the voluntary case was less important for the medievals (in some sense, quite the contrary), but because theories of divine concurrence with voluntary agents in particular usually presupposed a theory of divine concurrence with created causes in general.

Regarding the authors I consider, I hope to demonstrate that they form some meaningful debates, which debates, at the same time, illustrate some important changes in how thinkers addressed the issue in the thirteenth and subsequent centuries. And while it is difficult to avoid all kinds of arbitrariness in such a selection, I concentrated on those figures who were influential either among their contemporaries or later, or who were unique enough to take the discussion into new territories.

Overall, there is an historical, a systematic, and a methodological upshot of the dissertation. On the historical side, I shed some light on some medieval figures and what they thought about causation and divine concurrence. I will mention some interpretational debates in the individual chapters, and I also treat some authors (Durand of St.-Pourcain, Peter of Palude, Peter Auriol, Gabriel Biel) whose accounts of divine concurrence have not received much attention lately. As William Courtenay once noted, ‘‘few problems are as central to the philosophy and theology of the late Middle Ages as the problem of causality’’ (Courtenay 1971, 74) and yet it is still a topic mostly set aside in the literature on medieval philosophy. The problem of divine concurrence is just one aspect of the more general problem of causation, but as will be seen below, it highlights an important and often overlooked difficulty that results from combining Aristotelianism with classical theism.

On the systematic side, I show that although the focus of the debate and the employed conceptual apparatus shifted, concurrentists remained occupied with avoiding both occasionalism and mere conservationism. As will be also seen, the question of divine concurrence is strongly intertwined with such seemingly unrelated issues as the nature of contingency, divine foreknowledge, or the demonstrability of the causal relation.

Finally, on the methodological side, I show that although we can learn a great deal about such contemporary philosophical problems as causation, causal powers, and divine action in the world by looking at the medieval discussions, this should be done with great care. For although it is tempting to abstract these medieval theories from their theological assumptions, nevertheless, as it will be shown here, even such seemingly purely metaphysical issues as the nature and scope of causal powers or the supposed necessary connection between causes and effects are unintelligible in the medieval context without the theological framework in which they originally arose.