The previous post of the series addressed in brief Scotus' argument for the existence of a first efficient cause; this post will address Scotus' argumentation that such a being could not in principle be caused to exist by anything else.
Recall that Scotus' first efficient cause is defined thus: (i) it brings other things into existence of its own power, and (ii) nothing brings it into existence or actualizes it in any way. Scotus furthermore argues that such a being could not in principle be brought into existence by anything else. How?
Scotus says: Such a being [viz., a first efficient cause] cannot be produced and is independently able to produce an effect. This was proved above, for if such a being could cause only in virtue of something else or if it could be produced, then either a process ad infinitum or a circle of causes would result, or else the series would terminate in some being which cannot be produced and yet independently is able to produce an effect (p. 45).
His argument, then, seems to go like this. If something can be brought into existence, then its exhibiting its causal powers would ultimately be dependent in this case upon its being actualized by something else. This is true if it exercises its causal powers in a per se causal series, of course, but also even if it operates in a causal series ordered per accidens; as we have seen, per accidens chains are ontologically dependent on prior per se chains, as anything can only produce an effect in virtue of some form within it which gives it the power to act so. And as previously argued, such a chain of causes has to terminate in something which can produce of itself and is not -- cannot be -- actualized by anything else.
Another way to think of it may be like this. Anything that exists but is not produced by anything else must in some critical sense exist on its own, of itself. For that reason it could not in principle be brought into existence by anything else, since it would always preexist every causal chain of production. I can produce a child only because the child doesn't already exist; I can't produce my brother, however, because he already exists and so can't be produced. If the first efficient cause exists uncaused by anything else, therefore, in principle nothing could bring it into existence: it would always preexist every causal chain.
Scotus argues furthermore that if the first efficient cause has no efficient cause of its own, neither does it have a final, formal, or material cause. Arguing that the first efficient cause has no final cause, that is that it doesn't exist for the sake of producing anything in particular, he argues thus:
A final cause does not cause at all unless in a metaphorical sense it moves the efficient cause to produce an effect. Only in this way does the entity of what exists for the sake of an end depend on the end as prior. Nothing, however, is a per se cause unless the thing caused depends upon it essentially as upon something prior (ibid.).
This is not exactly the simplest passage to interpret, but the idea, I take it, is something like this. On Scotus' Aristotelian view, things have final causes, which are basically understood as that for the sake of which they exist. The final cause is typically that to which a thing naturally gravitates: e.g., as a tree towards growing, producing oxygen and fruits; a fish towards swimming, eating, and reproducing; etc. In a way, then, the existence of (say) a fish as a fish depends upon its fulfilling that which is a fish's final cause: if a thing did not swim, did not eat food, did not do all of the various fish-things, to that extent it is not a fish. This is what it would mean to say that the entity of what exists for the sake of an end depends on the end as prior.
Now if the first efficient cause had a final cause per se, that is to say, naturally and of itself, in virtue of what it is, then it would depend upon the fulfillment of that final cause in order for its existence. It would depend upon the fulfillment of that final cause as a prior condition of its own existence as an instance of its kind, in the same way that a thing must do fish-things in order to be considered a fish. But in a case like this, the first efficient cause would be actualized by something else: it would be made actual by the realization of its final cause, whereas we previously argued that the first efficient cause cannot be actualized by anything else.
Therefore the first efficient cause does not have a per se final cause, that is, it is not directed towards the production of anything in particular in virtue of what it is.
Likewise, Scotus continues, it cannot have any formal or material cause. Here the argumentation is a bit simpler to understand. A formal cause -- that is, the form by virtue of which a thing is actual, such as the arrangement of organic matter which makes it into a human body -- is an "intrinsic" cause of a thing, insofar as it is a part of the very existence moment-to-moment of a thing. The same is true with a material cause, the "stuff" from which a thing is made and by which it is individuated. Scotus notes that if a thing has no extrinsic cause, which is to say nothing outside of it which realizes or actualizes it in any way, then it could not have an intrinsic cause of any kind, either.
He argues like this, an argument hearkening back even to the neoplatonists:
Intrinsic causes are caused by extrinsic causes either in their very being or insofar as they cause the composite, or in both of these ways, for intrinsic causes of themselves and without the intervention of some agent cannot constitute the composite (p. 46).
On Scotus' ontology, things are composites of matter and form, just as a human body is a unity of organic matter and the particular arrangement of that matter required to form a human body. Now in general the unity of a composite of this sort requires the activity of an external agent, since the components themselves cannot of themselves explain the phenomenon of their unity. The parts of a bike do not explain why they are united in such a way as to form a bike, since they can clearly exist without being so united -- they once did before the bike was assembled. Likewise the parts of your body do not explain why they are united in a way that makes up a body; you can remove my organs, one by one, so that they are no longer united in a body-like way, which shows that the organs of themselves do not explain their unity.
Now if the first efficient cause is not caused to exist by anything else, then it cannot have internal composition of form and matter. For if it did, its internal composition would have to be explained by something else which composes it, it would need to be caused by something else, which we deny. This shows that the first efficient cause could not be a material being.