An Assessment of Soctus's Parisian Proof

The medieval period was the first philosophical era which generated many novel arguments for the existence of God or a first cause since antiquity (Shields, “Aristotle”, 1). The more famous arguments from the middle ages for God’s existence are probably Anselm’s ‘ontological argument’ and Aquinas’s ‘Five Ways’, and these arguments are still discussed today by philosophers. However, the arguments of Duns Scotus are often forgotten when looking at medieval arguments for God and rarely discussed by contemporary philosophers outside of medievalist circles (Pasnau, “Thomas Aquinas”, 1; Williams, “Anselm of Canterbury”, 1). Despite this, Duns Scotus provided very powerful arguments for God’s existence, and more than that, he provided ones that are exceptionally creative for the time, but are innovative by today’s philosophical standards as well (Williams, “John Duns Scotus”, 1).

The one I would like to focus on the most is his Parisian proof of the existence of God. It is a multi-step argument with many moves including the derivation of a first cause, and then plentiful arguments to show why the first cause is God. The Aristotelian notions of efficient and final causality play a key role in the argument, as will be seen later on, and these notions provide various ways for him to arrive at the Divine attributes. He also focuses a lot on the excellence or primacy of God in the Parisian proof and I will primarily focus on the part of the argument that deals with deriving a first cause and explicating God’s excellence or primacy. In the end, I think that we should view Scotus’s Parisian proof as a potent and successful argument for the existence of God.

The first place to begin when looking at the Parisian proof is Scotus’s early mention of the kinds of causality attributable to God as they provide the paths by which we can come to know God through natural reason. He writes that “there are only two sorts of causality that are distinct from each other, namely what pertains to an efficient cause and final respectively” (Wolter and Adams, “Parisian Proof”, 11). This serves to tell the reader how Scotus will later show God’s perfection and primacy.

The more important and fundamental notion involved in the Parisian proof is that of primacy as Scotus’ tries to prove God’s existence through various attributes of which God is the first in them. I have not come across this approach before and to my knowledge the Parisian proof is the first time that this kind of reasoning is employed in order to prove God’s existence. The beauty of this approach is that it provides a kind of flexibility in natural theology where, as long as there is a background metaphysics assumed, which can just be a minimal set of assumptions, there will be many philosophical paths to God. Moreover, the way Scotus goes about presenting these arguments is by showing how each causality or property leads to the same entity. Thus, by having a series of arguments which take different aspects of reality, but show how they all lead to the most fundamental member of reality, he derives the property of the first cause by adding the conclusion of each argument together. The result is a form of argumentation which is extremely flexible as long as it has efficient causality as its starting point, but also cohesive as each argument builds off of the previous one. 

With that in place, it is worth looking at some of Scotus’s demonstrations of God’s existence through showing that in different casualties or properties, there must be a prime member.. The first mode he talks about is how God has primacy in the domain of efficient causality: 

I prove that God is first of all by each such primacy, and begin with the primacy in this way. Some being is an effect, because it is produced. Now either nothing produces it, or it produces itself, or it is produced by another. It is not produced by nothing, for nothing is the cause of nothing. Neither does it produce itself, for - according to Bk. I, chapter nine of Augustine’s De Trinitate, “nothing begets itself.” Therefore it is produced by another. If by another, then this other is produced by nothing, by itself or by another - and so the process would continue indefinitely. Consequently, one must stop with something not produced, but which produces by its own power and not in virtue of any other, and this I call first. (Wolter and Adams, “Parisian Proof”, 12)

This is the first argument that Scotus presents for the existence of a first cause and it makes sense as the other arguments later on build off of the conclusion of this one. The argument itself is very simple since it starts from the basic fact that some beings are produced and so must have a cause to explain their existence. This results in there being a cause which is either produced by something else or is uncaused, and since the series of cause and effect cannot go on forever, there must be an uncaused cause. The kind of causality in the series Scotus describes is not explicitly stated, but I imagine that it is per se causality since that is what is mostly employed by medieval thinkers in these arguments and the kind of causality Scotus invokes later on (Knuuttila, “Medieval Theories of Modality”, 1). Some presentations of the argument that I have seen start from a modal premise where something can be produced, which is an even more limited starting point than the presentation above, which, I think, makes the argument even stronger. Nevertheless, the simplicity of the argument, both in its premises and its justification of the premises, makes the argument very powerful and convincing.

Moving forward, Scotus also shows that God is first in the order of excellence as well:

From this I infer secondly that some being is simply unexcelled. For in an essential order of essential or per se causes, a cause is always equivocal with respect to its effect, since it is of a different order than the latter. An equivocal cause, however, is always nobler than its effect, since - as equivocal - it can be neither less perfect or only equal in perfection with its effect. For this would be equivalent to saying that every other more perfect organism could be produced by a fly, since - according to you - no greater perfection is required of an equivocal cause than exists in its effect. (Wolter and Adams, “Parisian Proof”, 30)

The argument, again, is very simple in structure, although his use of the term ‘equivocal’ can be a little confusing. By my lights, he uses the term to imply a difference which is not shared between two things, specifically things that are either more or less fundamental. This makes sense as insofar as God is more fundamental than human beings ontologically, the two are equivocal to each other in the order of fundamentality insofar as they are more or less fundamental than each other. There also seems to be a notion of causality, or at least per se causality, where the cause is greater than the effect. This makes sense as less fundamental members of a per se causal chain have less being than the more fundamental members of the chain. The argument then concludes that there must be a greatest member of the per se chain since each per se chain has a first, or most fundamental, member and so this first member would be the greatest member of the chain. The argument seems to involve efficient causality, but focuses on the relations between different members of an efficient causal chain which is per se and so it builds off of the previous argument. This is rather beautiful from the viewpoint of natural theology as it is not an argument separate from the previous, but rather is inextricably tied to the previous argument and so inherently comes with it. It reduces the number of arguments used in order to prove God’s existence. Moreover, it is an example of how Scotus analyzes different aspects of causality in order to derive the Divine Attributes, which makes them an integral part of his argument rather than something which needs to be examined after and separately from arguments for a first cause.

The final part of the proof I would like to examine is his argument that God is first in the order of final causality:

If something is first as an efficient agent, then some also exists that is first as an end, i.e. something that cannot exist or function as final cause only in virtue of some other end. Every per se or efficient cause acts for the sake of some end. This we glean from Bk. II of the Physics. Now a prior efficient agent acts for the sake of some prior end, therefore, the first efficient agent acts for the sake of the final end. But such an agent never acts principally or ultimately for anything other than itself. Hence, it acts for the sake of itself as end. Thus it follows that the first efficient agent will also be the ultimate or first end. For were an agent to act for the sake of some end other than itself, then something would be more noble than the first efficient agent, because anything that is removed or distinct from an agent intending the end, is more noble than the agent (Wolter and Adams, “Parisian Proof”, 31)

This final example of how Scotus builds off of previous arguments in order to prove different aspects of God. He assumes the existence of a first efficient cause and then demonstrates that it must also be the primary final cause because all per se causes act for some end and since all efficient causes act for a prior end, the first efficient cause must have itself as its end, thus entailing that the first efficient cause is the primary final cause as well. This is just another example of how Scotus’s arguments build off of one another and simplify the natural theology needed to prove God’s existence.

In conclusion, even though Blessed John Duns Scotus is not as discussed by contemporary philosophers as medieval figures like St. Thomas Aquinas and St. Anselm, he is, in reality, an incredibly innovative and sophisticated thinker. This fact is very clearly seen when analyzing Duns Scotus’s Parisian proof of God’s existence as it is an example of how God, as well as His Divine Attributes, can be arrived at through many avenues of causality, and properties, that are found within Aristotelian metaphysics. The ones I explored were efficient and causality, as well as Scotus’s notion of excellence, which show how the primacy of the first cause implies that the first cause must be God. The Parisian proof should be studied by contemporary philosophers of religion, especially as the so-called ‘gap problem’, the problem of proving that the first cause or necessary being is God, will likely be the primary topic of debate for the next few decades. Scotus shows us that the path to showing that the first cause is God can be made clear, as long as there is a background metaphysics, like Aristotelian metaphysics, which properly understands the different aspects of being and their relations. As long as such a background is established, the philosophical path to God is never that long.

Works Cited

Knuuttila, Simo. “Medieval Theories of Modality.” Stanford Encyclopedia of Philosophy, Stanford University, 15 Apr. 2021, plato.stanford.edu/entries/modality-medieval/. 

Pasnau, Robert. “Thomas Aquinas.” Stanford Encyclopedia of Philosophy, Stanford University, 7 Dec. 2022, plato.stanford.edu/entries/aquinas/.

​​Shields, Christopher. “Aristotle.” Stanford Encyclopedia of Philosophy, Stanford University, 25 Aug. 2020, plato.stanford.edu/entries/aristotle/. 

Williams, Thomas. “Anselm of Canterbury.” Stanford Encyclopedia of Philosophy, Stanford University, 16 July 2023, plato.stanford.edu/entries/anselm/.

Williams, Thomas. “John Duns Scotus.” Stanford Encyclopedia of Philosophy, Stanford University, 11 Oct. 2019, plato.stanford.edu/entries/duns-scotus/.

Wolter, A., and M. Adams. “"Duns Scotus’ Parisian Proof for the Existence of God.” Franciscan Studies, vol. 42, 1982, pp. 248–321.