Showing posts with label medieval philosophy. Show all posts
Showing posts with label medieval philosophy. Show all posts

Monday, January 04, 2016

Metaphysics and Ontology V

The Question of Demonstrative Science

Like all medieval theologians, Luther was well-educated and very interested in logic.  He knew his Aristotle very well, lecturing on the great philosopher when in graduate school.  It is thus important that we know something about Aristotle's views on demonstration if we are to get clear on what Luther is doing in his more technical work where he thunders against "a logic of faith."

Aristotle argued in the Posterior Analytics that the deepest scientific knowledge of a thing required that thing to be grasped in terms of its necessitating causes.  Accordingly, the demonstrative syllogism produced the deepest knowledge (Eileen Sirene, "Demonstrative Science," in Cambridge History of Later Medieval Philosophy, p. 497).  Through such a syllogism knowledge of the fact was established (demonstratio quia) as well as knowledge of why this fact must obtain (demonstratio propter quid).

Toward the end of the first quarter of the 13th century, Robert Grosseteste became the first in the Latin west to comment on Aristotle's entire Posterior Analytics.  While he agrees with Anselm and others that the truth of a thing is its conformity with the rationes in the divine mind, he holds that the truth of a proposition is found in the conformity between what the proposition asserts and what is the case (Sirene, p. 502).  Grosseteste's commitment to a theory of divine illumination affects his interpretation of the Posterior Analytics.  While Aristotle indicated that experience and induction lead to an intuitive grasp of first premises in demonstrative proofs, Grosseteste grounds first premises in a "direct or indirect irradiation of his mind by divine light" (p.503).  Without such illumination no certainty is possible.

Aquinas downplays illumination as a necessary epistemic feature of this life, claiming with Aristotle that we can grant first principles and definitions through experience.  As it turns out, Aquinas assigns to the role of demonstrative science a small subset of the set of all truths, for most of what we claim to know is opinion, not scientia.  The latter demands both demonstratio quia and demonstratio propter quid, something lacking in the former.

Scotus relaxes the Aristotelian requirement that knowledge of something demands that one know why it necessarily happens.  Because of his commitment to the potentia dei absoluta, Scotus denies that knowing x presupposes that we know why x must be what it is.   The fact that it is an x is completely consistent with the possibility God could have willed ~x.  Scotus thus changes the nature of demonstrative science from the project of discerning what is necessary in nature to finding instead what is possible or compossible within it.  This has repercussions for his theory.  While demonstrative science could establish the connections among general truths, it is incapable of explaining why this particular was instantiated at this particular time.  This cannot be proved because God could always have changed his mind and not brought that particular into being. Here as elsewhere, voluntarism seems to push towards nominalism and the contingency of the individual.  

The great architect of the via moderna, William Ockham follows Aristotle in claiming that better known premises provide warrant to affirm the truth of those propositions entailed by them.  But, he realizes that "the resulting sciences are collections of true propositions, and not necessarily a mirror of the inner constitution of nature" (p. 513).  They can be only contingent propositions because God is the only necessary being.  Ockham does say that knowledge acquired by demonstration is not different in kind from knowledge by experience (p. 514), but understands this to mean that demonstrative knowledge needs to presuppose experience, not the other way around.  Jean Buridan follows Ockham on the difficulties of establishing an Aristotelian demonstrative science of nature, holding instead that such reasonings must allow for linking propositions which are almost always true with others of the same kind (p. 517).

Metaphysics and Ontology IV

E. What is the Role of the Senses in Acquiring Knowledge?

We have been surveying some of the metaphysical issues of the fourteenth century, issues that were still of concern when Luther was studying for his M.A. at Erfurt. We have discussed the question as to the proper subject matter of metaphysics, the relationship between the essence and existence of a thing, the issue of actuality and potency in incorporeal beings, and the question of the ontological status of universals with concomitant inquiry into the nature of individuation and identity.  Another important issue for 14th century theologians concerned itself with the metaphysics of knowing and the reliability of sense perception in acquiring knowledge.  Since the development of Christianity presupposed an Augustinian standpoint in which philosophy is in conformity with the revealed tenants of the christian faith, the task was to retain the harmony of faith and reason while still allowing empirical  access of, and affording general ontological status to, the external, non-divine world.

It is important to recall that Augustine and much of the Christian tradition presupposed the doctrine of divine illumination, holding that the mind confronts not its own concepts or ideas, but ideae, rationes, forms or species.  These were trans-subjective entities, not "subjective mental features" (Owens, "Faith, Ideas, Illumination and Experience," in The Cambridge History of Latter Medieval Philosophy, p. 442).  As Aristotle was rediscovered in the West, however, it became more important to give an account of the possibility and limits of knowledge gained through sensation, an account that sometimes produced considerable tension with the older illumination theory.  The problem was how to proceed in producing such an account, when knowledge was thought to be an incorporeal affair.  In other words,  how could the realm of the corporeal cause the suitable movements in the incorporeal assumed necessary for knowledge?  Whereas the Neoplatonic illumination starting point privileged the ontological status of ideas over material objects, (and in so doing assumed that secondary substance had more reality than primary substance), the Aristotelian focus on the ontology of primary substances seemingly reversed the situation entirely, affording no real existence to ideas -- and demoting secondary substance to a matter of the conceptual.

In the early part of the thirteenth century William of Auxerre tried to reconcile the older view of the divine illumination of religious faith with Aristotle's notion that we can attain knowledge through the senses.  He did this through developing Aristotle's assertion in De Anima that "the soul is in a way all things" (p.445).  William reasoned that although the thing known is potentially in the knower, the material intellect nonetheless had to receive its species from corporeal objects (p. 446).  The material intellect must receive the form abstracted from sensible things, forms called by his time species.   Owens writes: "the existence of things in the Augustinian intelligible world was being aligned with their potential existence in the soul's material intellect, and in each case 'existence' was regarded as metaphorical" (446).

William, however, rejected the Aristotelian notion of the active intellect, believing instead that the material intellect could itself know singulars and universals, and make true judgments about them.  (His view might be regarded as a precursor to the positions assumed by Hobbes, Locke and the other empiricists, for the object itself somehow impresses its species upon the thinker thereby forming an idea.)   Albert the Great, however, writing in 1245 advocates that an agent intellect is clearly needed in order to get the species into the material intellect.  He writes, "".  .  . unumquodque phantasma set particular determinatum: et ideo neccese est ponere agem universale in intellectu" (Summa de creatione II, 55, 1, ad 2m; Owens, p. 448).   The light of the active intellect, supplemented by the light of the uncreated intelligible light, abstracted the species from the sense particular and "lit" up the material intellect by so doing.   In combining the Aristotelian idea of abstracting the species and  forming the potential intellect with the notion of light, Albert attempted to retain Augustinian-inspired illumination theory even while moving towards an Aristotelian position on knowing the objects of the senses.   Roger Bacon, however, rejects what he sees as Albert's concession to Aristotle, holding instead that the operation of the potential and active intellect can be wholly understandable from the standpoint of Augustinian illumination theory.

As is well-known, Thomas Aquinas wholly rejected illumination theory, holding knowledge depended upon an identity in difference between the human knower and the object known.  He writes:  "Secundum autem quod intelligit res alias, intellectum in actu fit unum cum intellectu in actu, inquantum forma intellecti fit forma intellectus, inquantum est intellectus in actu, non quod sit ipsamet essential intellectus . . . quia essentia intellectus manet uno sub daubus formis secundum quod intelligit res duas successive" (Aquinas, Sent., 49, 2, 1, ad 10m; Owens, p. 452).  While Aquinas spoke of universals existing in the thing, this way of speaking was derived from the actual existence of universals only in the mind (453).

Three more thinkers deserve comment, Henry of Ghent, Duns Scotus and William Ockham.  While we mentioned all three before, we did not connect any of the three to the question of illumination and the intellect.   As we discussed earlier, Henry spoke of the intentional object having a type of existence (esse essentia) that could be distinguished from the actual existence of the thing (esse actualis existentiae).  Henry thereby explicitly connects the possession of true sense knowledge with the doctrine of divine illumination (Owens, 454).  Scotus rejected illumination theory, claiming that the divide between particulars that really exist and universals that are mere abstractions from particulars is too sharp, and accordingly there must be some common nature by virtue of which Socrates and Plato are common to men and not Socrates and a tugboat.  Some type of unity and commonness must exist outside the mind, grounding the human mind's abstraction of a common nature among objects.  This nature was thought to be formally distinct from the haeccity (or individuating nature) of a thing.  Scotus held that this nature could be known either intuitively as existing or abstractly without regard to existence.  In a tipping of the hat towards illumination, Scotus admitted that considered abstractly an object's common nature could be seen to lie before the gaze of the mind illuminated by the divine.  William of Ockham rejected the notion of illumination entirely, however, claiming that special divine intervention could cause intuitive cognition in a subject even in the absence of an object.  Accordingly, it was not the character of the object that distinguished abstract and intuitive knowledge, but the nature of the acts themselves (p. 457).

Since there was rich discussion of intuitive and abstractive cognition in the fourteenth century, it might be useful to reflect more deeply on the distinction between intuitive and abstractive cognition.   Scotus held that the fundamental distinction between abstractive and intuitive cognition is modal: the latter deals with what is possible or necessary, while the former deals with what is actual (John Boler, "Intuitive and Abstractive Cognition," in The Cambridge History of Later Medieval Philosophy, p. 465).  Ockham understands intuitive cognition to concern the apprehension by which contingent propositions are cognized, and abstractive cognition simply as a cognition that is not intuitive.  For Ockham, intuitive cognition is "caused by this one rather than that one" (Bohler, p. 468).  Yet, pace Scotus, the object need not exist for Ockham to have an intuitive knowledge of it.  The distinction between the two can be understood this way: Scotus believes that the proper place for an act of knowledge to begin is in the object, Ockham holds that it properly commences in an act of unconditional beginning.  God causing an intuitive act of cognition in the absence of an object nonetheless forms an unconditional beginning to the act. Indeed, God can cause apparent intuitive knowledge of all kinds of non-existents through His potentia dei absoluta, the absolute power of God whereby he can do anything that does not involve a contradiction.  Interestingly enough, however, appeal to potentia dei absoluta did not seem to spur development of skeptical thinking in the 14th century as did Descartes' analogous appeal to the "evil demon" two centuries later.

It is intriguing to contrast Ockham, Scotus and Thomas on knowledge of singulars.   For Ockham, knowledge occurs through the application of the concept to the individual; for Scotus, through the apprehension of unity of the individual represented by a set of characteristics; for Thomas, by means of the "construction" of the object by the intellect through the organization of sensory data (Boler, p. 476).  The intellect, according to Thomas, provides the form by which the sensory manifold is constructed.  While Aquinas' view might have some similarities with Kant, the trajectory of Scotus and Okham is definitely toward the ontology of the individual assumed at the dawn of the Enlightenment.

Saturday, January 02, 2016

Metaphysics and Ontology III

C.  The Question of Potency and Actuality in Incorporeal Creatures and the Possibility of Universal Hylomorphism 

While those defending a real distinction between esse and essentia regarded the latter as in potency to actualization by the former, those rejecting it simply conceived potency as all of that which God could have brought about, even though He had perhaps not done so.  Accordingly, those in the first camp could speak of a "subjective potency" (potentia subjectiva) of the essentia toward existence, while those in the second claimed there was only an "objective potency" (potentia objective) of the nonexistent esse/essentia complex toward existence (Wippel, p. 407).  While subjective potency presupposes there is a subject which could either have existence or not, objective potency simply asserts that while a substance with its qualities in fact does not exist, it nonetheless could.  Thinking of existence E as a predicate, the first claims that there is an x such that Ex, while the second that there is not an x such that Ex.

Universal hylomorphism approached the question by claiming that the form/matter distinction applies to all of created reality, even the realm of the incorporeal.  Advocates included Roger Bacon, Bonaventure and Gonsalvus of Spain.  Critics were legion, including William of Auvergne, Albert the Great, Thomas Aquinas, and Godrey of Fountains.  Those of the first camp generally regarded Avicebron or Augstine as adumbrating their own views, while thinkers of the second group appealed to Aristotle in substantiating their position.  Thinkers divided on the notion of prime matter, with advocates of universal hylomorphism tending to opt for a realm of pure potentiality, e.g., Albert, Thomas, Siger and Giles.  The Franciscans, on the other hand, seemingly advocated that any definite matter whatsoever had some degree of actualization, because actualization is necessary for matter to be definite and particular. Representatives included Richard of Middleton, Scotus, Henry of Ghent and William of Ockham.

D.  The Question of Universals 

 Plato had famously held that universals such as 'man' and 'whiteness' exist part from their instantiation in existent objects.  Those committed to such a view in the Middle Ages are generally termed "realists," asserting that universals are real regardless of their worldly exemplification and  their relationship to the thinker.  Moderate realists, on the other hand, claimed to be following Aristotle in holding that natures really do exist in individual things of which they are their natures.  If a bovine nature exists in Gertrude, Bessy and Bossie -- a general nature by virtue of which each of the three is a cow -- what is it that ultimately individuates Gertrude from Bessie and Bossie?   Is it the accidents of Gertrude that make her not Bessy?  But this seems wrong on Aristotelian grounds because the primary substances which Gertrude and Bessy are must individuate apart from any accidents.  But what could be a metaphysical constituent of a substance that individuates particular cows?  If not an accident, then perhaps it could be an individual nature.  Yet if such a nature exists, what is its relationship to the general nature by which each of the three individuals are cattle?  These issues dominated metaphysical discussion in the fourteenth century.

Duns Scotus famously argued the general nature common to each individual, must someone exist in each individual without a possibility of existing apart from some individual or other.  If Jack is going to be more similar to Jill than a tugboat, then there must be something common to Jack and Jill that is not found in Jack and the tugboat.  This common nature, which exists apart from human awareness, perception, conception and language, is nonetheless not numerically one.  Marilyn McCord Adams writes that for Scotus, "human nature is numerically one in Socrates and numerically many in numerically many distinct particulars, or thisnesses, that are numerically one and particular of themselves and that contract the nature, which is common of itself, rendering the nature numerically one and particular as well" (Adams, "Universals in the Fourteenth Century," Cambridge History of Later Medieval Philosophy, p. 413).  Just as Socrates is particularly white by virtue of the inherence of whiteness in him, so is he particularly Socrates by virtue of the particular contraction of the general nature in him.  Accordingly, human nature cannot be universal in re because it is not numerically one and particular in itself.  For Scotus, it is simply axiomatic that nothing predicable of many can be numerically one and particular.  But while the universal cannot exist in re because it is neither numerically one and particular, Scotus admits that it can exist in mente as an object of thought.

Scotus' position is that the nature which is one from the standpoint of what it denominates, is nonetheless many in numerically distinct particulars.  So what is the relationship of this one and many?  Here Soctus introduces his notion of a formal distinction: "The nature and contracting difference are formally distinct, or not formally the same" (Adams, p. 414).  While Scotus offers different metaphysical accounts of how this is possible, he seems to settle on discriminating between a distinctio simpliciter and a distinctio secundum quid.  While every man is an animal, and man is not metaphysically distinct from animal, they are formally distinct in that animal has "more perfection" than man because it can be predicated of more things (Adams, p. 416).  

William of Ockham took a very dim view of Scotus' metaphysical machinations stating, in fact, that Scotus' position is internally incoherent.  He has a number of arguments that I won't rehearse here.  Maybe the best of his arguments is the following:

  • Scotus holds that the principle of individuation (e.g., what makes Socrates Socrates) or contracting difference is numerically one and particular, and thus cannot be common to numerically distinct particulars.  (Assumption 1)
  • He also assumes that the nature and contracting difference are formally distinct, that is, not formally the same.  (Assumption 2)
  • According to Ockham, however, on assumption 1 it is not metaphysically (or logically) possible for the humanity of Socrates to exist without Socrateity.  This is the case, even though it is logically possible for Socrates to exist without a particular whiteness existing in him.  
  • More generally, no contracting principle that operates on a general nature to particularize it is contingently instantializable; e.g., the humanity in Socrates can only be Socrates' humanity and the humanity in Plato can only be Plato's humanity. Therefore, it is not possible that one and the same nature can exist in many things.  (Contradicting Assumption 2)
There are a number of other positions in the fourteenth century that deserve at least some mention.  Walter Burley attempts a moderate realism claiming that "the whole universal (secundum se totum) exists in each of its particulars and is not numerically multiplied by its existence in numerically distinct particulars" (Adams, p. 423).  Henry of Harclay, along with Ockham, attacked Burley's views, the former holding that "everything that exists in reality is essentially singular -- i.e., logically incapable of existing or, as a constituent of, numerically many simultaneously" (429).   Henry believes that individual substances act on the intellect in two ways, either confusedly or distinctly: "The universal is a thing confusedly conceived, and a particular is the same thing distinctly conceived" (430).   A universal and particular are thus the same thing, although they are distinct in reason.  (One might say, they could be described differently.)  Throughout the 14th century nominalism gained strength, even if it was not always able to show that its realist opponents were committed to explicit contradiction.  At some point, the attempt to save realist vocabulary seemed to many disputants simply obscurantist with regard to the underlying metaphysical facts.

Saturday, December 26, 2015

Metaphysics and Ontology II

B.  The Question of the Distinction between the Essence and the Existence of a Thing

It is important to realize that medieval philosophers assumed a very large ontological domain.  They needed not only to account for the metaphysical constitution of the material objects encountered in the world, but also incorporeal beings like God, angels and human souls. While God's metaphysical simplicity and His necessary, uncaused character presented a unique challenge to general metaphysical principles, created entities such as angels seemed to cry out for a metaphysical framework of the created order wide enough to include their constitution. The medieval question of the relationship between essentia (essence) and esse (existence) in created beings arose because of the need to cast a metaphysical account broad enough to include both corporeal and incorporeal created beings.

Boethius first suggested that entities had two aspects: essence and existence.  In Axiom II of his De Hebdomadibus, he writes, Diversum est esse et id quod est . . .   In Axiom VIII he opines, Omni composito ilid est esse, aliud ipsum est (Wippel, 392, fn. 38).  These comments seemingly conform with Avicenna's view that existence and existence are robustly distinct. Averroes and followers demurred, arguing that if an object has real being only by virtue of that which is superadded to essence, then why not claim there is something else superadded to existence making it even more real (393)?  Boethius' comments and the differing interpretative traditions of Avicenna and Averroes set the stage for this metaphysical controversy.

Aquinas advocated the real metaphysical constitution of essence and existence, suggesting in his youthful De ente et essentia that essence or quiddity is the potency of any created being which can be actualized into existence by God.  While the first is necessary for understanding of the thing, the second is not, coming, as it were, from outside the thing's quiddity and uniting with its essence in composing the real thing.  In the Summa contra Gentiles Thomas writes, . . . et sic in quodlibet creato aliud est nature rei quae participat esse, et aliud ipsum esse participatum (SCG I, q. 13).  The participating nature is in potential to the actuality of the participated nature. As Wippel points out, over and against Avicenna, for Aquinas, since "existence has no quidditative content in addition to that of the essence which it actualizes," . . . "neither essence nor existence can exist independently of each other"(395).  Thomas writes: Unde patet quod hoc quod dico esse est actualitas omnium actuum, et propter hoc est perfection omnium perfection (q. 7, a. 2, ad 9).  To say that existence (esse) "is the actuality of all acts and the perfection of all perfections" is to claim that ens (a being) participates in esse (to-beness).  Essentia both receives and limits esse and thereby produces ens. Real composition is necessary in a being in order to account for the quidditive limitation of that being.

While Aquinas held to the real distinction of esse and essentia, he did not employ the infelicitous language of Giles of Rome who asserted in his Theoremata de esse et essentia that esse et essentia sent duae res (th. 19, p. 127), and that since res ergo ipsa quod est esse est in genere substantiae, it is per consequens intelligitur quod esse sit alia res ab essentia (Giles, q. 9 & q. 11, in Wippel, p. 392).  Giles clearly is trying to account for all of created being in analogy with the form/matter distinction for material entities: Dicemus ergo sicut generatio facit scire materiam aliud esse a forma, sic creatio facit nos scire essentiam esse aliud ab esse (th. 5, q. 9).  Giles' use of res in characterizing both esse and essentia suggests a very robust, real esse/essentia distinction, and it was his formulation of real distinction that was severely criticized by Siger of Brabant, Godfrey of Fontaines and William of Ockham.

Siger admitted that ens was composite, but instead of construing this composition along the form/matter analogy, he suggested that the analogy between substance and accident is better.  Godfrey claimed the distinction was only secundum rationem (according to reason) and not due to the metaphysical composition of the thing.  Godfrey, in fact, argued for a real identity between esse and essentia, for whatever can be said truly of the first can be said truly of the second and vice versa (Wippel, p. 401).  Essentia has only potential being prior to God's bringing it to be.  Since the significatio of essentia and esse are the same, the two must be identical.  Ockham mounted ingenious philosophical arguments against the real distinction of esse and essentia, claiming that if former were really distinct from the latter, then it would have to be either a substance or accident.  But it is neither an accident because esse is not a quality or quantity, nor a substance because esse is neither a matter, form, their composite, or a separate entity (Wippel, p. 402).  His modal argument precedes thusly:  If a and b are distinct then it is possible for a to obtain without b, or for b to obtain without a.  But it is not possible for God to create essentia without esse or esse without essentia, therefore esse and essentia are not distinct.

Henry of Ghent, James of Viterbo and Duns Scotus sought to establish a position between a real ontological distinction between esse and essentia, and their ontological identity which possesses only a distinction according to reason (secundum rationem).  Henry of Ghent's views, though not widely affirmed in the subsequent tradition, are nevertheless quite interesting.  Anticipating Meinong, he affords a type of being to essences (esse essentiae) that is not existential.  Because God exists and has knowledge of all possible and existing entities, essential being has a type of existence prior to actual existential instantiation.  The divine will thus communicates actual existence (esse existentiae) to a subclass of esse essentiae entities.  Henry ingeniously opts for a new type of distinction, one of intention, in sorting esse and essentia.  While the existence of a thing does not add to its essentia, the external relation of actually being efficiently caused by God in creation marks a third path between a real distinction and real identity.  Esse essentiae is sorted from esse existentiae) by the fact that God has actually created the second.

James of Viterbo apparently tried to distinguish between essentia and esse semantically, according to primary and secondary significance.  While the modus significandi (mode of signification) of an abstract term signifies only the thing's essence, that of a concrete term, while signifying essentia primarily, signifies secondarily the thing having esse.  So existentia signifies essentia primarily and secondarily it signifies that which is conjoined with essentia in an existing subject (Wippel, p. 405).  Finally, and most famously, Duns Scotus searched for an intermediate position by admitting that while esse and essentia are not separable in contingent fact, they are not identical in all possible worlds.  Although oftentimes referred to as the "formal distinction," Scotus scholars have differed on what precisely is meant.  Scotus also opines that while abstract cognition has essentia as its proper object, intuitive cognition has existentia.  Whether either this epistemic point or the modal point legitimately establishes a formal metaphysical distinction between things never found apart is, of course, open to further debate.

Thursday, December 24, 2015

Metaphysics and Ontology I


Addressing the issue of “Luther and ontology” requires clarity first on what ‘ontology’ is.  Within Luther scholarship, unfortunately, there has sometimes been confusion on this basic issue.  Thus it is that I will first get clear on the nature of ontology and how it relates to metaphysics.  Only then will I review some of the secondary literature on Luther and ontology, pointing to areas within Luther’s theology where the question of ontology is deeply important for his theology.  Finally, I will suggest areas of continuing research.  For both Luther’s theological predecessors and Luther himself, ontology and semantics are closely related.  Interpreters of Luther sometimes have forgotten this, ignoring ontological aspects of his own thinking, and thus projecting their own ontological assumptions upon the theology of the great Reformer.  
1.1 The Meaning of Ontology and its Relationship to Metaphysics
Many mistakenly believe that the terms 'metaphysics' and 'ontology' are coextensive, referring to the same set of philosophical issues. This is not so.  Both terms have a long and rich history that must be untangled in order to grasp the nature of their connection.  As it turns out, while the term 'ontology' ('ontologia', 'ontology', etc.) generally applies to a sub-region within metaphysics that specifically concerns general questions of being, the discipline of metaphysics is much wider, investigating the general (or universal) features (or principles) of reality presupposed by concrete experience as such.   
Historically, the term 'metaphysics' derives from the collection of 14 books by Aristotle appearing in his corpus after the Physics.[1] Andronicus of Rhodes probably titled these books "Ta meta ta phusika," perhaps thereby warning students that these texts should only be undertaken after mastering the books of the Physics, all dealing with the principle of change.  Metaphysics, on the other hand, connotes the study of those things that do not change. It is the discipline dealing with first causes, with God and the Unmoved Mover.  
Inwagen and Sullivan provide the following list of "metaphysics" according to Aristotle's conception.[2]

  • Being as such
  • The first cause of thing
  • That which does not change
Aristotle, however, also famously believed that metaphysics is concerned with being qua being.  Accordingly, it is not just a study of first causes and unchangeable things, but examines objects "from a particular perspective, from the perspective of their being beings or things that exist.  So metaphysics considers things as beings or existents and attempts to specify the properties or features they exhibit just insofar as they are beings or existents."[3]    Considered in this way, metaphysics is a universal discipline, studying notions such as identity, difference, similarity, dissimilarity, and the categories that grant the possibilities of for being to be.   
Inwagen points out that what we mean by "metaphysics" greatly expanded in the seventeenth century, thereby confusing matters even more.  While older metaphysics dealt with traditional questions of being as such, categories of being, universals and substance, metaphysics since the 17th century became increasingly concerned with questions of modality, space and time, persistence and constitution, causation, freedom and determinism, and the mental and the physical.            
Bruce Aune clarifies the relationship between general and special metaphysics that developed with the expansion of metaphysical questions in the seventeenth century. 
General metaphysics includes ontology and most of what has been called universal science; it is concerned, on the whole, with the general nature of reality: with problems about abstract and concrete being, the nature of particulars, the distinction between appearance and reality, and the universal principles holding true of what has fundamental being. Special metaphysics is concerned with certain problems about particular kinds or aspects of being. These special problems are associated with the distinction between the mental and the physical, the possibility of human freedom, the nature of personal identity, the possibility of survival after death, and the existence of God.[4]

Oftentimes scholars claiing that Luther is unconcerned with metaphysics or ontology are conceiving metaphysics in the later seventeenth century sense of the term, and not according to the concept present in Luther’s own time.
The word ontologie actually develops much later than “metaphysics,” occurring first in the German language only in the work of Rudolf Goeckel (1547-1628) and Jacob Lorhard (1561-1609), and is later defined more fully by Johann Georg Walch (1693-1775) in his Philosophische Lexicon as follows: 
Ontology concerns the doctrine of being, and is understood as a name of a new philosophy of science that treats being in general and its properties (l.c., s.v. Ontologie 1. A. 1726, 2. A. 1733, ND dieser Thoemmes 2001).

Ontology is thereby the study of being insofar as it is possessed by any kind of entity. Christian Wolff (1679-1754) famously distinguishes ontology as metaphysica generalis (inquiry into the general categories of being) from the metaphysica specialis dealing with God (natural theology), the soul (natural psychology), and the world (natural cosmology).[5]  
So in what did the subject of metaphysics consist in the High and Late Middle Ages?  The following is my own (rather incomplete) list of traditional metaphysical questions of the period: 

  •           In what does metaphysics consist?  Does the question of God fall under metaphysics broadly conceived, or is it a question of a "divine discipline" (scientia) falling outside of metaphysics proper? 
  •           What is the relationship between the essence and existence of a thing, and what is the ontological status of the distinction putatively separating them? 
  •           How can the distinction between actuality and potentiality be conceived in spiritual matters where the distinction between form and matter fails to obtain?  
  •          Do universals exist and, if so, what is their ontological status?  
  •          How is individuation possible without matter, and how should identity, distinction and similarity be conceived? 
  •          What is the role of the senses in acquiring knowledge, and can this role be squared with the notion of illumination stretching back to Augustine?  
  •      Can knowledge of God be "demonstrated," and what precisely is the nature of such a demonstration.   
John Wippel points to the two traditions developing after the rediscovery of Aristotle's Metaphysics.  In Book IV Aristotle talks of a discipline concerned with being as being and not with questions about particular attributes of being characteristic in the various other disciplines.[6] In Book VI, however, Aristotle mentions a "divine science" concerned with immovable and separate entities. Presumably, it is precisely because there is a domain of separate, immobile entities that physics cannot be considered the first science.[7]  Reconciling these two conceptions of metaphysics -- first science dealing with being qua being and first science dealing with separate and immobile entities -- spurred lively philosophical discussion in the Middle Ages as to precisely what metaphysics is. 
Wippel points out that Duns Scotus in his Questions super libros Metaphysicorum asks the question as to the proper subject matter of metaphysics by contrasting the approaches of Avicenna and Averroes: 
Is the subject of the Metaphysics being insofar as it is being (ens inquantum ens) as Avicenna holds?  Or is it God and the intellectual (Intelligentiae) as the commentator Averroes suggests? [I. I(1891-5, v. 7, p. 11)]  

After discussing the question of whether metaphysics can have God as its subject, Avicenna concludes that since God's existence can be demonstrated, and since no particular discipline can demonstrate its own subject matter, then only metaphysics broadly conceived, as the study of ens inquantum ens, can establish divine existence. 
While Avicenna placed God under the metaphysics of being qua being, the other great Islamic commentator Averroes disagreed, holding that one does not need to establish God as the subject matter of a unique discipline, for the existence of God can be established by physics.  Accordingly, the subject matter of metaphysics, ens inquantum ens, concerns substance primarily, not God.  Metaphysics properly studies substance, but includes that "separate substance which is the first form and the end or final cause of all other substance" (387).  Physics establishes that there is such a separate substance, and metaphysics examines that substance as well as all other substances.  Most 13th and 14th century thinkers followed Avicenna: Metaphysics concerns ens inquantum ens, not divine being. 
While Sigar of Brabant and Duns Scotus both include the question of God within metaphysics, the latter explicitly denies that God can be its subject matter since metaphysics deals with the universal and the question of God is particular (389).  Scotus writes: 
Even though God, however, is not the first subject of metaphysics, God is nevertheless considered in that science in a most noble way (nobilissimo modo) in terms of which [God's being] can be considered as acquired naturally in another discipline (sciential) (Ord. Pros., pars 3, q. 2, n. 193).  

Is is well-known Aquinas differs from Scotus in his notion that the being of God cannot be included under the idea of ens communes (being in general).  However, despite the controversy on whether metaphysics or metaphysics + physics can establish that the cause of the ens communes, Thomas is certain that the question of God is properly included within metaphysics (390-91).  Ockham differs from all of these thinkers, holding that metaphysical propositions have different subjects, accordingly both ens inquantum ens and God are proper subjects of the objective propositions of metaphysics.         



[1] Aristotle did not call these books by this term, but named the discipline at work in it either 'first philosophy' or 'theology', calling the knowledge to which it aims, 'wisdom'.  See Michael Loux, Metaphysics.  A Contemporary Introduction, 3rd ed., (New York: Routledge, 2006), 2ff.    
[2] van Inwagen, Peter and Sullivan, Meghan, "Metaphysics", The Stanford Encyclopedia of Philosophy (Spring 2015 Edition), Edward N. Zalta (ed.), URL = .
[3] Loux, 4.
[4] Aune, Metaphysics: The Elements (Oxford: Basil Blackwell, 1986). 
[5] The preceptive reader will recall that Kant subjects all of these three (rational theology, psychology and cosmology) to merciless attack in his Critique of Pure Reason.  As the domain of metaphysics was expanding in the seventeenth century, the term 'ontology' gained currency in dealing with select metaphysical questions directly pertaining to being.  Elisabeth Maria Rompe's Die Trennung von Ontologie und Metaphysik: Der Ablösungsprozess seine Motivierung bei Benedictus Peterius und anderem Denkern des 16. u. 17. Jahrhunderts (Bonn: Universität Bonn, 1967 diss.) provides a valuable insight into the process of the separation of the two terms.  
[6] John  Wippel, "Essence and Existence," in The Cambridge History of Later Medieval Philosophy, edts. Kretzmann, Kenny & Pinborg,(Cambridge: Cambridge University Press, 1982), 385-410. 
[7] Ibid., 385.