2. Forms and Elements: Taurellus's Immaterialism

In Taurellus's Kosmologia (Reference Taurellus1603), one finds a group of remarks on atoms and atomism that, as Christoph Lüthy has pointed out, pose a consistency problem. Taurellus remarks that “atoms are the principles of magnitude” and that everything “is composed out of first, minimal and individual parts” (Taurellus Reference Taurellus1603, 145). Likewise, he remarks that these “individual parts” touch each other but do not become continuous, but remain merely contiguous, without merging into a single unity (ibid., 119). Yet, shortly before the first of these passages he also distances himself from atomism: “What is said about atoms from the position of the atomists, is irrelevant. For atoms are not the matter of the world or of the worlds to be brought into being” (ibid., 142–143).Footnote ¹³ Taken together, these passages are certainly bewildering because they seem to threaten Taurellus's ontology with inconsistency: the first two passages seem to imply a commitment to the view that atoms are the ultimate building-blocks of the compositional structure of the world, while the last passage seems to deny the reality of material atoms.Footnote ¹⁴

The inconsistency, however, may be apparent only because the emphasis of Taurellus's disclaimer with respect to the doctrines of the atomists may concern exactly the idea mentioned, namely, that atoms are the matter of the universe. Once one denies materiality to the ultimate constituents of reality, the claim that the ultimate constituents of reality possess some properties traditionally associated with atoms – being indivisible, being principles of magnitude, being capable of touch but not of fusion, being capable of motion – is compatible with denying that atoms are the matter of the universe. Of course, if this should turn out to be Taurellus's view, he would have to say something about how these properties could be understood as properties of immaterial entities. As it will turn out, Taurellus indeed does have something to say about these issues. But first it has to be established whether or not Taurellus is committed to an immaterialist conception of the ultimate constituents of reality.

In his later writings, there is little textual evidence to settle this issue in any definitive way. In De Rerum Aeternitate (Reference Taurellus1604), Taurellus reinterprets prime matter as “the nothing” out of which the world is created, and therefore denies that prime matter could be regarded as a constituent of created things, without however developing any sustained argument for either claim (Taurellus Reference Taurellus1604, 420). Similarly, in a passage from his annotations to the Opera Omnia of Arnaldus de Villanova (ca. 1240–1311), Taurellus denies the reality of prime matter and claims that “it is the common opinion of physicians that there exists nothing prior to, nor more simple than the elements” (Arnaldus of Villanova 1585, col. 8).Footnote ¹⁵ In fact, the dismissal of prime matter and the adoption of the medical conception of elements is a move that is already found in Melanchthon's Initia Doctrinae Physicae (see Melanchthon [1549] Reference Melanchthon1555, fol. 110v). However, Melanchthon's motivation seems to have been an aversion against unnecessary curiosity rather than an insight into any substantive philosophical problems connected with the doctrine of prime matter (see ibid.). And there is no hint that Melanchthon intended to give any novel interpretation to the medical conception of the four elements (air, fire, water, earth). In both respects, Taurellus diverges from Melanchthon. To be sure, in his annotations to Arnaldus de Villanova's Opera, Taurellus does not expand on how the medical view relates to his own denial of the reality of prime matter. But he points out that he has given a demonstration of why there exists nothing prior to, nor more simple than, the elements, in two other works: his commentary on Hippocrates's De natura hominis and his Philosophiae Triumphus (Arnaldus of Villanova 1585, col. 8). Since the former work either has never been published or has been lost,Footnote ¹⁶ we have to focus on the latter work.

In fact, in Philosophiae Triumphus, Taurellus develops an intricate argument for denying that prime matter enters into the constitution of things. At the same time, while Taurellus accepts the traditional view that air, fire, water, and earth are the four elements, he offers a reinterpretation of the nature of these elements. The argument starts with a consideration of the motivation for introducing the notions of form and prime matter. As he describes it, the motivation arises out of the view that in natural things there are contrary properties: active properties such as the capacity of bringing forth changes in other things, and passive properties such as the capacity of undergoing change through the agency of other things. If these properties are understood as contrary, then they seem to require two different origins (assuming that no single origin can bring forth contrary properties). For this reason, the active properties of natural things were seen as requiring the existence of forms, while the passive properties of natural things were seen as requiring the existence of primary matter (PT, 292). However, Taurellus challenges the assumption that active and passive properties of natural things should be regarded as contraries. This is why: “Nothing takes on its contrary but rather cedes when the contrary comes; but passivity increases with the increase of activity” (PT, 284).Footnote ¹⁷ Hence, his argument against the contrary nature of active and passive properties is that an increase of passive power is compatible with an increase of active power. But if activity and passivity are not contraries, “they are present in the same subject and proceed from the same cause” (PT, 292).Footnote ¹⁸ At the same time, Taurellus holds on to the assumption that the active properties of things have to be explained by the existence of an active principle. This is why he does not eliminate the notion of form from his ontology. On the contrary, because active and passive properties are not contraries, he believes that they proceed from forms alone: “We say that a thing is active and passive with respect to the same form; but in such a way that action is its proper effect, while the other does not arise from matter conjoined with it but from an externally existing contrary principle” (PT, 294).Footnote ¹⁹

Regarding forms as the unique kind of origin of the active and passive properties of natural things also leads to a reinterpretation of the compositional structure of the world. Clearly, it implies that natural things cannot be understood as composites of form and prime matter. This is why, in Taurellus's view, forms are the only beings underlying the compositional structure of the world: “Matter plainly does not exist, and nothing but forms can be and can enter composition” (PT, 280).Footnote ²⁰ And again: “[O]nly forms can be conjoined and can compose a whole” (PT, 278).Footnote ²¹ Accordingly, “mixture or composition is . . . a mere conjunction of forms that in no way changes them” (PT, 276).Footnote ²² At the same time, understanding composition in this way implies that through composition no new form arises that could confer genuine unity onto the composite:

Hence, composition itself is an accident that belongs to a multiplicity of genuine unities, and the changes that relate to the composition and separation of parts take place on the level of accidents.

Taurellus uses the idea of a hierarchy of forms to explicate a sense in which one can speak about matter without being committed to matter as a constitutive principle of natural things. His reinterpretation of secondary matter in terms of subordinate forms allows Taurellus to continue to talk about bodies (corpora) and corporeal beings (entia corporalia) (see PT, 160–162; 182; 352–354; 552–554). As he puts it, “if it is not understood as a less noble form, . . . matter does absolutely not compose anything” (PT, 278).Footnote ²⁴ Thus, there is a sense in which one can talk about matter which uses a traditional connotation of the notion of matter, namely, that it is something less noble that underlies something more noble (see PT, 296). Thus, even if the idea that prime matter underlies form is given up, the structure of something less noble underlying something more noble can be upheld. More specifically, less noble forms can be understood as the subjects of more noble forms. In Taurellus's view, things receive the character of subjects “for the same reason that makes that they are less noble, such that forms that are within nothing else but serve as subjects for something else are the most ignoble, but those that do not serve as subjects for anything else but are within something else are more noble” (PT, 330).Footnote ²⁵ Here, Taurellus takes up an idea that is already found in the work of Schegk but also modifies it in an interesting way. To get a grip on the parallels and differences between Schegk and Taurellus on these issues, it will be useful to consider some details of Schegk's account of mixture.

Schegk took a keen interest in the work of Alexander of Aphrodisias (fl. ca. 200 AC) and published a Latin translation of Alexander's De mixtione. The core idea of this work is expressed in the following account of the role of the tempering of elemental qualities in mixture:

Similarly, Schegk maintains that both inanimate forms and animate forms depend on the mixture of elements:

Schegk points out that this conception of the origin of animate forms has the consequence that “an animate form also is a physical form” (ibid.).Footnote ²⁸ In fact, such a view of the origin of souls is found in Alexander's De anima. According to Alexander, the soul “is a power and form, which supervenes through such a mixture upon the temperament of bodies; and it is not a proportion or a composition of the temperament” (Alexander of Aphrodisias [1495] 1559, 78; cf. Alexander of Aphrodisias Reference Bergeron and Dufour2008, 104 (De anima 25.6–8).Footnote ²⁹ As Victor Caston has argued, talk about supervenience should here be taken in the technical sense of a co-variation of mental states with bodily states (Caston Reference Caston1997, 348–349). Moreover, Caston emphasizes that, for Alexander, the soul possesses causal powers that are more than the aggregates of the causal powers of the elements (ibid., 349–350). In the sense that Alexander ascribes distinct new powers to souls as well as to the forms of non-animate composites such as chemical blends, Caston characterizes Alexander as one of the ancient thinkers who were committed to emergentism (ibid.).

Within this emergentist framework, Alexander maintains that the notion of matter can be applied not only to characterize primary matter and secondary matter (understood as primary matter informed by elemental forms) but also as a relative notion that can characterize the relation between higher and lower levels of beings. Alexander explains that if the soul is understood as a form that supervenes upon the mixture of simple bodies and their temperament, then “no doubt this temperament by its essence plays the role of matter” (ibid., 79).Footnote ³⁰ Somewhat differently, Schegk suggests that the forms that are dominated by the most perfect form of the entire composite behave “as if they were the mediate matter [materia mediata] with respect to the perfect forms” (Schegk Reference Schegk1585, 42). What these two versions of a relative notion of matter have in common is that the subordination relation is analyzed in terms of final causation. As Alexander puts it: “An entelechy and perfection is of such a nature that it cannot exist without that to which it belongs, very much like a limit cannot exist without that whose limit it is” (Alexander of Aphrodisias [1495] 1559, 76; cf. Alexander of Aphrodisias Reference Bergeron and Dufour2008, 90 (De anima 17.12–14).Footnote ³¹ Likewise, Schegk writes: “Some forms are said to arise later, and as it were with the advent of some perfection, such that the later form does not destroy the earlier form but rather perfects it” (Schegk Reference Schegk1585, 42).Footnote ³²

As we will presently see, Taurellus accepts some aspects of emergentism. However, what he clearly rejects is the view that souls could emerge from the mixture of elements. As he puts it: “Soul is not so earth-like that it would arise out of the seed or that it would decay together with the body” (PT, 168).Footnote ³³ More generally, he rejects the view that substantial forms could emerge from the mixture of elements: “Because through generation something arises that is really one, viz., substantial form, we hold that this is not simple with respect to the conjunction or some other accident and also not composite, whether it arises from a single being or from many beings” (PT, 274). Moreover, as he makes clear immediately afterwards, the situation in which something simple arises out of many beings is a situation in which a mixture is resolved into its elementary components (ibid.). Consequently, Taurellus cannot invoke the idea that, by emerging from the temperament of elements, a substantial form confers perfection upon the elemental forms. This is why he offers a different explication of the sense in which the less noble forms could be regarded as the “matter” of the nobler forms:

According to this line of thought, a form is more noble than other forms if it is more prone to cause changes in other forms, and form is less noble than other forms if it is more prone to receive the effect of the activities of other forms. Passive changes of forms thus are seen as a result of the contingent activity of other forms together with the internal constitution of the forms that have undergone change. In this sense, in Taurellus's view the subordination relation between substantial forms reduces to relations of efficient causation between substantial forms.

The ensuing view of the nature of elements is one that ascribes the origin of all activities found in the corporeal world to the activities of immaterial forms. This becomes clear when Taurellus uses a thought experiment to argue against the assumption that the most common activities of bodies should be ascribed to prime matter and only the activities that are specific to a different kind of bodies should be ascribed to immaterial forms:

As an example, Taurellus uses the qualities of the element earth: it is touched and moved, cold and dry. The view that he criticizes would ascribe the qualities of being touched and moved to prime matter because these qualities are shared by other elements and only the qualities of coldness and dryness to form because this combination of qualities is specific to earth. To undermine this view, Taurellus asks us to consider a counterfactual one-element universe: “Assume that nothing but earth would exist, which could bring forth these activities, would you not attribute the activities that belong only to earth to its form?” (PT, 348).Footnote ³⁶ The implication of this thought-experiment seems to be that, if in a one-element universe there is no reason to ascribe the qualities of being touched and moved to prime matter, then there is also no reason to make such an ascription in the real universe because the constitution of other elements does not contribute anything to the constitution of the element earth.

Consequently, Taurellus ascribes to forms qualities that are traditionally ascribed to prime matter: “The constitution that can be ascribed to form without matter is such that it is both touched and moved” (PT, 348).Footnote ³⁷ Of course, one may wonder whether immaterial forms are the right kind of entity to be touched and moved. For instance, Alexander denies that souls have by themselves a capacity of motion (Alexander of Aphrodisias [1495] 1559, 77; cf. Alexander of Aphrodisias Reference Bergeron and Dufour2008, 98 [De anima 21.22–22.7]). However, Alexander presents this as an immediate consequence of his view that, because souls supervene upon the mixture of elements, they cannot be separated from the body (ibid.). Once this view is rejected, there is no need for denying to substantial forms the capacity of local motion. The only qualification that Taurellus adds to his view that substantial forms are capable of motion is that souls that possess sensation and will are not moved by necessity, as inanimate substantial forms are, but rather by their own free will (PT, 350). Things may be more puzzling with respect to the capacity of touch, and indeed Taurellus seems to have been aware of this difficulty when he writes “In some sense, incorporeal beings also show the capacity of touch, both because they move the bodies with which they are joined, and because the soul is in various ways afflicted by some demons” (PT, 352).Footnote ³⁸ Thus, the capacity of touch reduces to relations of efficient causation both between soul-like substantial forms and between the souls and subordinate substantial forms that constitute the human body.

What is more, Taurellus regards the activities of substantial forms as the origin of all of the forces found in the natural world: “Nature is the unique principle of corporeal things and consists in a single substance, not in two or three substances. This substance seems to be manifold because it expresses itself in various forces” (PT, 376).Footnote ³⁹ But how should the relation between the variety of physical forces and the activities of substantial forms be characterized? Interestingly, in this respect Taurellus takes up an aspect of emergentism, and here it becomes clear that he accepts a notion of composite form, as long as composite forms are not regarded as something substantial:

Accordingly, what emerges from the mixture of elements is a plurality of novel, but non-substantial causal powers. To be sure, Taurellus does not go into a detailed analysis that tells us how exactly different higher-level causal powers arise from the active powers of elements. But at least he indicates a sense in which his immaterialist account of elements can provide an ontological framework for understanding the origin of the causal powers of composites – these powers can be understood as supervening upon and emerging from the tempering of elemental qualities without, however, thereby giving rise to a novel kind of substance.

The passage just cited may be remarkable in a further respect. Taurellus's own subject index refers to this passage as the only one in the entire book that explicates the nature of quantity (PT, 588). This is why his remark about quantity may bear more weight than may be obvious on first sight. The view that is implied by the rejection of the axiom of the equivalence of one-ness and being is that multitudes can be regarded as real beings because they possess causal powers that none of their constituents possess. Moreover, in the final remark of the passage quantity is clearly attributed not to substances but to beings that are constituted by a multitude of constituents. Taken together with its immediate context, this remark may suggest that quantity, like the pharmacological powers of medicaments, could be regarded as one of the causal powers that supervene upon the mixture of elements. If this is what Taurellus has had in mind, then extension could be understood not as a property of immaterial forms themselves but rather as an emergent property that their composition brings about.

Certainly one may have wished that Taurellus had clarified in more detail the relation between the active and passive features of immaterial forms and the observable qualities and powers of the corporeal world. Nevertheless, there is strong textual evidence that indicates that Taurellus's ontology does not imply anything like material atomism. Rather, the only entities that at a basic level underlie the compositional structure of the world are form-like elements. As it will turn out presently, his immaterialist conception of the compositional structure of the universe is crucial for understanding how Taurellus believed that his conception of the ultimate constituents of reality could support his goal of providing a philosophical foundation for the doctrine of creation. In his view, only forms have the right kind of ontological dependence on God – a kind of dependence that supports the doctrine of creation and excludes the alternative doctrine of natural things as eternal divine attributes. To substantiate this suggestion, we will have to proceed step by step.

3. Forms and Elements: Taurellus's Theological Motivation

Let us start with the view that Vorstius's critics ascribed both to Vorstius and to Taurellus: the view that God is a quantum that is limited and possesses accidents. As it turns out, such a reading does not adequately represent either Vorstius's or Taurellus's views concerning divine extension. Vorstius holds that God is infinite not only with respect to duration and potency but also with respect to omnipresence (Vorstius Reference Vorstius1610, 221).Footnote ⁴¹ Because God is omnipresent, there is a quantitative aspect to his nature; however, Vorstius is clear that “this does not relate to physical or corporeal and sensible quantity but has to be understood with respect to the true and by no means fictional but evidently for us imperceptible and spiritual magnitude of God” (Vorstius Reference Vorstius1611, 2).Footnote ⁴² Also, Vorstius emphasizes that he “never claimed that God is finite unless perhaps in the sense that God is a definite being, that is, a determinate being on its own that is distinct from other beings” (ibid., 2–3).Footnote ⁴³ Accordingly, when Vorstius talks of the “place” of God, he does not mean any physical place in the Aristotelian sense – a place defined by the boundaries of other bodies – but rather wishes to express the view that God extends throughout the whole of space (ibid., 3).Footnote ⁴⁴

On first sight, the views of Vorstius may seem to differ from Taurellus's conception of divine infinity, because Taurellus's conception seems to involve a sense in which God is a material being. Consider the following passage: “We say that God is almighty both in the sense that he has an infinite potency due to his substance, and in the sense that he also has infinite matter due to his essential characteristics, that is, one that in no way hinders the agent through any potency of acting” (PT, 484).Footnote ⁴⁵ However, although infinite matter, in a certain sense, here seems to be included among the essential characteristics of God, Taurellus gives an explication that clearly marks talk of “infinite matter” as metaphorical. “Infinite matter” as a metaphor for the infinite divine potencies indicates that there are no further potencies that could function as an external impediment to divine agency. Such a metaphorical usage of the notion of infinite matter evidently does not imply that God has material (and, hence, limited) properties. Likewise, Taurellus suggests a metaphorical usage of the notion of prime matter. As he puts it, with respect to God prime matter is “the NOTHING” (in capital letters) out of which God creates the world (ibid.).

The connection that Taurellus establishes between the notion of prime matter and the notion of nothing strongly differs from the use of the epiteton “nothing” that is often attributed to matter in the Neoplatonic tradition. In the sixteenth century, there were at least two influential ways of explicating the idea that matter is something that lacks positive determinations. Perhaps the most careful early modern statement of the first way of explicating this idea is found in Carolus Bovillus's Libellus de nihilo (Reference Bovillus and Bovillus1509).Footnote ⁴⁶ As Bovillus explains, what is meant by calling matter “nothing” is that matter by itself lacks differentiation into individual entities and that matter, for this reason, can be described only by means of negations (Bovillus [1509] Reference Bovillus and Bovillus1510, fol. 63v). Nevertheless, he suggests that matter possesses reality in the sense of being an undifferentiated mass in which all beings are potentially contained and out of which all beings arise (ibid.). In his view, matter also possesses permanence in the sense that it was created at the beginning of the world and is immune to corruption (ibid., fol. 64r). Accordingly, he emphasizes that matter is not altogether nothing but rather occupies an intermediary position between being and nothing: strictly speaking, it is not nothing but “close to nothing” (ibid., fol. 63v).

A different version of Neoplatonic matter theory was first formulated by the sixth-Johannes Philoponus, a sixth-century commentator on Aristotle, and made prominent again in Gianfrancesco Pico della Mirandola's Examen vanitatis doctrinae Gentium (Reference Pico della Mirandola, Pico della Mirandola and Pico della Mirandola1520). Philoponus understands prime matter as something undetermined except for its three-dimensional characteristics.Footnote ⁴⁷ Still, three-dimensional extension is thought of as being connected by its nature with forms. As Pico emphasizes, according to Philoponus, “space is a place that, even if by itself it is vacuous of body, nevertheless is never an actual vacuum, just as we say that matter differs from form but is never devoid of form” (Pico della Mirandola [1520] Reference Pico della Mirandola, Pico della Mirandola and Pico della Mirandola1573, 1189).Footnote ⁴⁸ In fact, Philoponus maintains that the dimensions “are not without body but in the body” (Philoponus Reference Philoponus and Dorotheus1554, fol. 83v).Footnote ⁴⁹ As he points out, this is what sets his view apart both from Aristotle's conception of place as the surface of the surrounding bodies and from the atomists’ conception of a vacuum as an immaterial receptacle of bodies. His argument for the mutual existential dependence between extension and body concerns the conditions for the activity of forms and for the divisibility of bodies:

According to this line of argument, only if three-dimensional extension is understood as the prime matter that is the subject of forms can the extension of bodies and the active and passive powers of forms explain why bodies are divisible (see De Haas Reference De Haas1997, 117–119).

What these different versions of Neoplatonic matter theory have in common is that they regard matter as a constituent of created beings – either as a constituent that explains the origin of the passive qualities associated with mass or as a constituent that explains the activity of forms and the divisibility of bodies. By contrast, as we have seen in section 2, Taurellus denies that prime matter is a constituent of created beings and holds that immaterial forms have active and passive characteristics of their own. His point is not that matter, due to its lack of determination, is “close to” nothing, nor that matter is undetermined except for its three-dimensional characteristics. Rather, when he calls prime matter “nothing” he has in mind a strict identity statement. This is why it is a suitable metaphor for what is there before the divine act of creation, namely, no created being. Prime matter in this metaphorical sense is absolute non-being.

Evidently, such a conception of prime matter does not lead to a conception of God as a material being that is spatially separated from the created world. In fact, for Taurellus creatures are separated from God in an entirely different sense. As he argues, “since an infinite substance fills out everything, nothing can be separated from it.” This is why we differ numerically from God “not with a view to God's being in us and our being in him but in the respect that we differ due to our substance” (TP, 412).Footnote ⁵¹ Here, God is clearly not characterized as a being that possesses limited extension but rather as a being that extends throughout the whole of space. And this means that no creature can be spatially separated from God. Rather, the only sense in which creatures can be understood to be separated from God thus must have to do with the nature of their substance. And to differ from God with respect to substance presupposes that creatures are substances. This is why establishing the sense in which creatures can be understood to be substances is so central for Taurellus's project.

When Taurellus discusses the relation between creatures and God, he considers two different kinds of effects:

Taurellus is clear that the latter hypothesis would lead to a kind of substance monism according to which the world would be an accident of the divine substance: “If the world is not separated by its substance from God but always exists conjoined with him and in the same way will persist to eternity, it does not subsist in itself . . . But it will be an accident of God that can neither be separated from him nor persist separately” (PT, 428).Footnote ⁵³ Of course, such a view of the relation between God and the world might seem attractive to some philosophers. Not so to Taurellus. In his view, the world cannot be an accident of the divine substance both due to the nature of God and due to the nature of natural things. As to the nature of God, Taurellus argues that regarding the world as a divine accident has the absurd consequence that one would have to ascribe to God finite accidents: “The absurdity cannot be avoided that an infinite substance will be defined by finite accidents, for the nature of accidents consists in limiting substances or to define them is some other way” (PT, 430).Footnote ⁵⁴ In particular, “it would follow . . . that we are the perfection of the substance of God because actions perfect the substance from which they proceed” (PT, 492).Footnote ⁵⁵ Taurellus argues that this cannot be right because, due to his infinity, God cannot be said to have accidents at all: “Because God exists infinitely with respect to substance, he does not receive anything through which he could be defined, which is the reason why accidents are as foreign to him as possible since they limit or define substances” (PT, 454).Footnote ⁵⁶

As to the nature of things, Taurellus's view that forms are the only beings that underlie the compositional structure of the world contributes to explicating a sense in which the world differs by its substance from God. In the preface to the second treatise of Triumphus Philosophiae Taurellus points out that there is a close connection between his criticism of the theory of prime matter and his theological aim of defending the doctrine of creation. This connection has to do with a consequence that, in his view, follows from the theory of prime matter, namely, that prime matter is an accidental being. As he remarks, the Aristotelian principles “want matter which is nothing by itself to be something accidentally. For if this is true, it will be an accident, not a substance” (PT, 240).Footnote ⁵⁷ As Taurellus argues, something analogous holds for the conception of form in the hylemorphistic tradition: “The natural philosophers have stated that natural forms cannot subsist without a subject; if this were admitted, they would not be substances but accidents, because substances are not in something or from something but subsist through their own force, while one says of accidents that they do not subsist but rather are in something” (PT, 318).Footnote ⁵⁸ This objection applies in particular to the emergentist conception of substantial forms found in Alexander of Aphrodisias and Schegk. Alexander explicates the relevant sense of substantiality by pointing out that the qualities of the form that emerges from elemental qualities cannot be separated from matter and therefore have to be ascribed to the entire form-matter-composite (Alexander of Aphrodisias [1495] 1559, 72; cf. Alexander of Aphrodisias Reference Bergeron and Dufour2008, 70–72 [De anima 5.3–18]). Evidently, such an explication is vulnerable to the objection that it is not clear how a principle that itself depends for its existence on matter could be regarded as something substantial. What is more, Taurellus does not think that a conception of matter and form as accidental beings could be given a consistent formulation. As he argues, a theory of mutual existential dependence between primary matter and form leads to the absurd consequence “that the effect is in this case its own cause. For what gives essence to something else is a cause, a form that cannot subsist without matter is its effect; and conversely because matter is absolutely nothing without form, its subsistence depends on its own effect” (PT, 320).Footnote ⁵⁹

Still, one may wonder why Taurellus did not take the difficulties of the assumption of mutual existential dependence between prime matter and form as an argument for adopting an immaterialist ontology rather than for adopting the medical theory of elements. At this juncture, the limitation of the available source materials is unfortunate because, in Philosophiae Triumphus, Taurellus does not discuss the medical conception of elements. As he points out, he has covered this issue in his commentary on Hippocrates's De natura hominis (Arnaldus of Villanova 1585, col. 73); but since this commentary is no longer extant, we are left with an argumentative lacuna. Nevertheless, when his insistence on the notion of substantiality in Philosophiae Triumphus is read in conjunction with a remark about the medical conception of elements from his annotations to Arnaldus of Villanova, it becomes clear why the medical conception of elements is unsuitable for achieving his theological goals. Arnaldus characterizes the medical conception of elements as follows:

Taurellus comments upon this passage:

Thus, due to its emphasis on the role of elemental qualities in bringing about qualitative changes in the human body, the medical conception of elements does not offer the theoretical resources for explicating the sense in which elements can be regarded as substances. This is possibly why Taurellus felt the need of going beyond a medical analysis of the nature of elements by understanding elemental qualities as the outcome of the active and passive powers of immaterial forms.

In fact, in his view, a theory of immaterial forms is exactly what yields an analysis of the substantiality of elements. This is so because, once the assumption that form depends existentially on prime matter is given up, there is no need to regard form as an accidental being: “Tell me, does nature subsist by itself or does it subsist in something other? If you say that nothing underlies it, why shouldn't one be allowed to ascribe the same to form, such that it is nature and subsists without matter?” (PT, 376).Footnote ⁶² Taurellus's immaterialism about the basic constituents of the compositional structure of reality thus explicates a sense in which these basic constituents are substances. This is crucial for Taurellus's characterization of the relation between God and the world: “Because the world is separated from God by its substance, it is not conjoined with him from eternity” (PT, 426).Footnote ⁶³ The ensuing view of the relation between God and creatures accepts creation dependence of creatures on God but denies the dependence of creatures’ continued subsistence on God. Consider the following characterization of physical change: “Nothing happens accidentally if not something that is in itself is presupposed. The natural philosophers propose this as an axiom, that something active does not have any effect unless the subject on which this action is directed possesses the disposition to receive this activity” (PT, 266–268).Footnote ⁶⁴ Thus, what natural things, in Taurellus's view, possess are active potencies that bring forth changes in other natural things and passive potencies that make them capable of undergoing changes through the agency of other natural things. These natural changes are determined by natural active and passive potencies of immaterial forms, but these natural potencies cannot bring about any kind of change for which immaterial forms do not have a disposition. This is why these changes do not carry with them any threat to the subsistence of the world: “Because the world is substance and because one says that something is changed naturally when it is changed in a direction for which it has some disposition in it, it follows that if the world does not decay in this way, it does not carry any potency [for decay] in itself” (PT, 498).Footnote ⁶⁵ In this sense, the existence of natural things is due to a divine act of creation but the subsistence of these natural things does not require any continuous divine concurrence: “Things . . . have received substance from him, but they do not continue to receive it” (PT, 492).Footnote ⁶⁶ This is the crucial point that Taurellus's rejection of prime matter is meant to make. Only if the subsistence of the forms that underlie the compositional structure of the world as well as their active and passive potencies do not depend on continued divine agency can the hypothesis that the world is an eternal accident of the divine substance be refuted. And in this way, an immaterialist conception of the ultimate constituents of reality contributes to an indirect defence of the theological doctrine of creation ex nihilo by refuting the rival doctrine of the eternity of the world.