Abstract
Medieval scholastics share a commitment to a substance-accident ontology and to an analysis of efficient causation in which agents act in virtue of their powers. Given these commitments, it seems ready-made which entities are the agents or powers: substances are agents and their accidents powers. William of Ockham, however, offers a rather different analysis concerning material substances and their essential powers, which this article explores. The article first examines Ockham’s account of propria and his reasons for claiming that a material substance is essentially powerful sine accidentibus. However, the article subsequently argues that, given Ockham’s reductionism about material substance, only substantial forms – never substances – are truly agents and powers. Thus, a material substance is essentially powerful but only by courtesy – per accidens, as Ockham calls it – because it has a non-identical part, its substantial form, which does all the causal work by itself, per se.
1 Introduction*
Medieval scholastics explain efficient causation in the natural world as the interaction between powerful individuals.1 In any causal scenario, there is something which acts (quod agit) and something by which it acts (quo agit). The former they call the ‘agent’ (agens) and the latter the agent’s active source of ‘power’ (potentia).
Which entities in the natural world are agents or power sources? Since medieval scholastics share a commitment to a substance-accident ontology, the answer seems ready-made: substances are agents and their accidents power sources. Thus, when a pot of water is heated over a flame, the causal analysis would include the following: the fire substance (the agent), in virtue of its accident of heat (a power source), heats the pot of water.
Such an analysis is offered by Thomas Aquinas (1225–1274).2 And it can even be found in the writings of contemporary ‘powers theorists’ committed to a two-category ontology of substances and properties.3 But Aquinas’s analysis was criticized by many medieval scholastics writing after him.4 The aim of this article is to examine the analysis of one of these critics, William of Ockham (ca. 1287–1347), concerning material substances and their essential powers.
If Ockham is known for anything, it is his radically particular and parsimonious ontology: all that exists are individuals, and the only individuals that exist are substances and qualities.5 Clearly, Ockham has a taste for desert landscapes in positing only individual substances and their qualities. But some scholars have noticed that the individuals Ockham posits are modally and causally lush. For example, Ockham thinks a quality, such as heat, does not have a power for heating but is a power that produces heat.6 And he thinks immaterial beings, such as God, angels, and intellective souls, are causal agents identical with their own essential powers.7
But just how far into the natural world does Ockham extend this thesis of the identity between a substantial agent and its essential powers?8 Are material substances, like horses, plants, and even the elements, substantial agents identical with their essential powers in the way that immaterial substances are? As far as I know, this question has only been touched on by Aurélien Robert in his brief treatment of Ockham’s ontology of causal powers.9 Although Robert does not point to any particular text for the answer, he suggests that they are, and he uses the following analogy from the realm of artifacts to explain how.
According to Robert, if a key is the cause of a lock’s being opened, it is because of the key’s lock-opening power. But a key’s lock-opening power is identical with the key’s own nature, which is its strength (matter) and shape (analogous to a natural substance’s substantial form). In the same way, if a material substance is a cause of an effect, it is because of its power to cause that effect. But a material substance’s power is identical with its nature, which, according to Ockham, is its essential parts of matter and substantial form(s). Thus, material substances are causal agents identical with their own essential powers; no added accidents are necessary.10
But if Ockham thinks substances are powerful without accidents, what are his reasons for thinking so? And if it is because substances are identical with their own essential powers, how would this identity claim fit within his reductionistic claim that a material substance is nothing in addition to its essential parts taken together, united and conjoined? The aim of this article is to make a start on Ockham’s account of material substances’ essential powers by answering these two questions.
The article, in turn, is divided into two parts. In part 1, I examine Ockham’s account of propria and his reasons for denying Aquinas’s claim that, in addition to a substance’s essential parts of matter and substantial form, distinct (though necessary) accidents must be added in order for a substance to be powerful. According to Ockham, a material substance is sufficient to explain its own essential powers, and is, thus, powerful sine accidentibus. But is this sufficiency explained by a substance-power identity? In part 2, I will argue that a closer examination of Ockham’s metaphysics of material substances and their essential powers shows it is not. Given Ockham’s reductionism about material substance, I will argue that these essential powers are not identical with the substance but only with an essential part of the substance, namely, its substantial form. I will show that Ockham thinks substantial forms – never substances – are truly causally efficacious and powerful in the natural world. A material substance is only essentially efficacious and powerful by courtesy – per accidens, as Ockham will call it below – because it has a non-identical part, its substantial form, which does all the causal work by itself, per se.
2 Powerful sine accidentibus: Ockham’s Account of propria
According to Aquinas, a substance’s powers are distinct accidents, because essence and power are distinct in creatures.11 Some of these accidents are contingent powers, others are necessary powers. Among a substance’s necessary powers are its propria.12 These are “natural properties” (proprietates naturales) that “flow” (fluunt) as a “natural result” (per naturalem resultationem) from the essence of the substance as their active cause and principle.13
Now Ockham, like Aquinas, accepts the distinction between a substance and its necessary powers. But they disagree over the nature of this distinction and these powers.14 For Aquinas, necessary powers, such as propria, are particular kinds of accidents of a substance, distinct from and caused by the essence. Ockham, however, denies that propria can be accidents in this way, given his broader views about identity and distinction.
Although Aquinas and Ockham both countenance a real distinction in reality,15 according to Ockham’s own formulation, a real distinction obtains between things (res), and if two things are really distinct from one another, then it is logically possible for each thing to exist without the other, at least by divine power.16 Thus, if propria are accidents distinct from the subject, as Aquinas holds, then Ockham argues that they are things really distinct from the subject. And if they are really distinct, then it follows that a subject can exist without its propria (or vice versa). But Ockham argues that this is impossible, as seen in the following modal argument:
Any proposition that is affirmative simpliciter, which is not equivalent to a negative proposition, in which a proprium is predicated, is equivalent to a de possibili proposition. And this is because if it were not equivalent to a de possibili proposition, then that proposition would be able, by divine power, to be false at the same time that the proposition, in which existence is attributed to the subject, is true. From this it follows that any proposition of the following sort is contingent: ‘substance is quantified’, ‘every fire is hot’, ‘a human laughs’, and so on concerning other propositions of this sort. But propositions of the following sort are necessary: ‘every human is susceptible to instruction’, ‘every corporeal body is mobile’, ‘every human is risible’. These propositions cannot be false when the proposition, in which existence is attributed to the subject, is true, and they are equivalent to de possibili propositions. Just as this proposition, ‘every human is risible’, is equivalent to this, ‘every human can laugh’ … Moreover, the reason why the other propositions are contingent, such that they can be false at the same time that the proposition, in which existence is attributed to the subject, is true, is because God can make any created thing without the other, or at least the prior without the posterior.17
Ockham, like other medieval scholastics, sees a close connection between modality and power: what a subject can do is determined by the powers it has, some of which are necessary to it. And here Ockham says that any affirmative proposition in which a proprium term is attributed to a subject term, such as ‘risible’ to ‘Socrates’, is equivalent to a modal proposition expressing possibility, which is necessarily true if the subject exists. For example, if the proposition ‘Socrates exists’ is true, then the proposition ‘Socrates is risible’, which is equivalent to the modal proposition ‘Socrates can laugh’, is necessarily true (the assertoric proposition ‘Socrates is laughing’, however, is contingent).
But suppose that a subject and a proprium, such as Socrates and his risibility, were two things really distinct from one another. Then God could create them separately or at least make the prior (Socrates) without the posterior (risibility), such that the proposition ‘Socrates exists’ is true while the proposition ‘Socrates is risible’ is false. But since God cannot do these things,18 Ockham concludes propria cannot be particular kinds of accidents really distinct from the subject.
Instead, Ockham treats propria, along with the other four predicables (genus, species, difference, and accident), as particular kinds of attributions of a subject, predicated of it in distinct ways.19 According to Ockham, a proprium is a per se attribute (passio) predicated of the subject in the second mode of per se predication, because it is not included in the subject’s essential definition (although the subject is included in the attribute’s definition).20 And in propositions, a subject and its propria are convertible with one another salva veritate, suppositing for the very same thing, namely, the subject.21
Thus, rather than propria terms signifying distinct accidents inhering in and empowering the subject to act or be acted upon, as Aquinas thinks, Ockham instead thinks these terms signify the powerful subject itself and the types of acts that can be produced by it or in it:
And therefore, just as by this statement ‘every human can laugh’ it is not denoted that there is some other thing in a human, but it suffices that [laughing] can exist, because it suffices that a human can have an act of laughing; in the same way it is concerning this statement ‘every human is risible’. From this it follows that risibility is not something formally inhering in a human, as something other than a human, just as the ability to heat is not some other thing formally inhering in the heat. Just as the ability to heat does not signify anything except the heating principle by which [an act of] heating can exist, so risibility signifies nothing except a human who can have an act of laughing … It is therefore evident that the ability to heat is not something formally existing in the heating subject, and by the same reason, risibility is not something formally existing in a human, but it signifies a human who can have an act of laughing.22
According to Ockham, an essential power is nothing distinct from its principle. For example, the power to heat is not something formally inhering in the quality of heat, nor is the power to laugh something formally inhering in the human substance. Rather, these power terms primarily signify the principles – heat and humans – from which these acts are produced. And these power terms secondarily connote the types of acts – heating and laughter – that can be produced from or in these principles, as Ockham elsewhere makes explicit, saying that the predicate ‘to be naturally apt to navigate’ is a proprium of a human being “connoting something extrinsic to it, namely, an act of navigating.”23
In summary, it’s clear from Ockham’s account of propria that he rejects Aquinas’s view that distinct (though necessary) accidents must be added to empower substances.24 No recourse to accidents is necessary to make true these modal propositions concerning a substance and its essential powers. Material substances are sufficient to explain their own essential powers, and are, thus, powerful sine accidentibus.
3 Powerful per accidens: the Identity of Substantial Form and Essential Powers
But are material substances powerful without accidents, because they are identical with their essential powers? That is the substance-power identity claim. And one might take Ockham to be suggesting just as much in the preceding passage concerning a human substance and its risibility: substance = principle = essential power.
But matters of substance are more complicated for Ockham, because Ockham thinks a substance is nothing in addition to its form and matter.25 He writes:
Therefore, I say that besides the parts which are matter and form, there is not another third entity distinct from these, but there is a composite which is neither one part nor another, such that this composite is neither matter, nor form, but matter and form together, united and conjoined.26
According to Ockham, a substance is not identical with its matter alone, nor with its substantial form alone, but with both together, united and conjoined. But what makes his account reductionistic is that this union between matter and form is not a third entity distinct from these two. Thus, given his reductionistic account of substance, if the substance-power identity claim is true, then the agent and essential powers would have to be identical with the substance’s matter and substantial form taken together. However, a closer examination of Ockham’s metaphysics of material substances and their essential powers shows that Ockham never identifies the agent and essential powers with the material substance. Rather, he identifies the agent and essential powers with only one essential part of the substance, namely, its substantial form. This can be seen especially in Ockham’s frequent use of a metaphysical separation thought experiment to discover the agent and power source of a produced effect. Let us consider, first, how Ockham uses this thought experiment concerning a substance and its accidents, and then, second, concerning a substance’s substantial form and matter.
In his discussion in Reportatio II, q. 19, on the roles that substantial and accidental forms play in efficient causation, Ockham discusses whether a substance or its accidents are the efficient cause of an effect. Now, the idea of an effect proceeding from a substance shorn of its accidents, or from an accident unmoored from its substance, suggests that we have moved out of the “normal and natural” world of Aristotelian physics into the land of the metaphysically miraculous.27 However, the cases that Ockham considers are anything but miraculous. They are, in fact, ordinary causal scenarios in the natural world involving the causality of fire, vegetative souls, grass, and wine.
For example, concerning the question whether a new fire is generated from a fire substance or from the substance’s accident of heat (which Ockham thinks is really distinct from the substance), Ockham invokes the following metaphysical separation thought experiment in order to locate the agent and power source of the produced effect:
Likewise, when an effect is related to another thing in such a way that when that thing is posited, the effect can be posited, that thing has the notion (ratio) of a cause with respect to that effect immediately or mediately. This is sufficiently evident, because an effect sufficiently depends, etc. But when the form of fire is posited with heat, another fire can be generated, and when the form of fire is not posited – even if the heat is posited – the fire cannot be generated. Just as it is evident to the senses that if heat in the fire were separated and acted in water, it will never generate fire but only heat, therefore, etc.28
Ockham begins by stating that if an effect e can be posited when cause c is posited, then c is either an immediate or mediate cause of e. Now, as Ockham says elsewhere, if c is said to be an ‘immediate’ cause of e, then c directly produces e. But if c is a ‘mediate’ cause of e, then c only produces or conserves another entity, d, which itself is an immediate cause of e.29 Which role, then, does Ockham think the substance of fire plays here? Is the fire only a conserving cause of its accident of heat, which itself generates the new fire? Ockham thinks not. For if one were to posit the fire and the heat, a new fire would be generated, but if one were to posit the heat without the fire, no new fire would be generated; only heat would ever be generated. So, Ockham concludes, the fire substance is an immediate cause, not a mediate, conserving cause, of the new fire.30
After repeatedly invoking this metaphysical separation thought experiment for the other ordinary cases of efficient causation, Ockham proposes a general test for determining the immediate cause – or what he calls the “immediate, effective principle” – of the effect:
A substance is frequently the immediate, effective principle of an action, and also sometimes an accident is. But when it is so and when it is not, one must return, as I believe, to experience. For if we can know through experience that the substance alone, posited and conserved in actuality, can cause the effect without any accident from the part of the elicitive principle, then the substance alone is the immediate cause of the effect (concurring, of course, with God). But if we experience that an effect can be caused from an accident alone without a substance, then the accident is the immediate cause, not the substance. But if the effect cannot be caused without either, then each is a partial cause with respect to that effect. And this is generally true in every natural action.31
Ockham’s test can be explained as follows. Suppose there is a fire substance, S, and an accident of heat, a, inhering in S (which, again, are two things really distinct from one another in this scenario, according to Ockham). And suppose that the following proposition is true, ‘S has the power, φ, to produce heat’. What makes this proposition true? Is it S, a, or both S and a? Ockham thinks you can find the answer through repeated observation of S and a in the world in order to see where φ goes. If φ goes with S, then we know that S is the immediate, effective principle of φ-ing, not a. But if φ goes with a, then we know that a is the immediate, effective principle of φ-ing, not S. But if φ goes with neither S nor a, then we know that S and a are immediate, co-effective, partial principles of φ-ing (which Ockham thinks is generally the case in natural cases of efficient causation).
Now, Ockham’s claim – that repeated observation of a complete, substance-attribute package and its actions in the world can lead us to deep metaphysical insights into whether the substance, or its accidents, or both are the immediate cause of the effect – would strike most contemporary readers as deeply puzzling and mistaken. And many would find Ockham’s epistemological account unpersuasive of explaining how one comes to know via observation which is the immediate cause.32 But these epistemological matters need not concern us here. For what is crucial to notice here is what the natural world must be like metaphysically in order to ground the possibility of one even coming to such knowledge. For Ockham’s test assumes that substances and accidents can each be immediately efficacious of an effect – whether totally or partially – even while conjoined.
This assumption is seen most clearly in his treatment of Aristotle’s distinction between per se and per accidens efficient causation, which Ockham reinterprets in terms of parts and wholes. Here is Ockham:
And therefore, it can be said that a per accidens cause is that which acts through something other than itself; but something is not a cause of this sort unless it is a subject or whole having parts by which it acts. And in this way, it can be said that fire per accidens heats, and in the same way that a hot thing per accidens heats. And in the same way it can be said that a human per accidens thinks, and similarly, a whole per accidens acts, when the action does not belong to it unless by means of its own parts. And the reason for this is because this is said to belong per accidens to something when that thing is removed and nevertheless the [action] can exist. But when the fire is destroyed and the heat is preserved, nevertheless, the heating will be able to follow, because, as it will be shown in book IV [of the Sentences], an accident actually separated in this way can act just as when it is conjoined. In the same way, that action which belongs to a human by means of the intellective soul will be able to be elicited from the soul when separated as when conjoined; and therefore, an action which primarily belongs to the part is said to belong to the whole per accidens, because it belongs to it through another. Similarly, an action primarily belonging to an accident is said to belong to its own subject per accidens, because it belongs to it through another. And thus, by taking ‘per accidens’ broadly, according to which it is the same as ‘through another really distinct thing’, thus, it can be conceded concerning the subject of an accident and concerning a whole, whose action belongs primarily to the part, that it is an agent per accidens, and in this way, is a per accidens cause.
But a per se cause is that which causes not through some other really distinct thing but through itself, such that when this is posited, and when every other thing is set aside which is not a cause in another genus of cause, the effect will be able to follow. And in this way, heat itself is the per se cause of heat, because when it is posited, and every other thing is removed which does not have the notion of a cause, it will be able to follow in the disposed and approximated patient; and therefore, heat per se causes heat, because it does not cause through another. And in this way the intellective soul itself per se causes an intellection and volition, because it does not cause through another, unless according to which the word ‘through’ (per) names a circumstance of a partial concurring cause.33
According to Ockham, a per accidens cause is that which acts through another really distinct thing belonging to it; a per se cause does not act through another thing but through itself. Given this distinction, a per accidens cause is a type of what Ockham earlier called a ‘mediate cause’, whereas a per se cause is what he earlier called an ‘immediate cause’ or ‘immediate, effective principle’. Returning, then, to the example of the fire substance and its accident of heat – but this time concerning the production of a new quality of heat – which entity plays which role? Here again we see Ockham’s metaphysical separation thought experiment at work. According to Ockham, if one were to separate the accident of heat from the fire substance, the power to heat would go with the accident, since it would continue to produce heat, even if the fire substance were destroyed. And if one were to separate the intellective soul and destroy the human substance, the soul would continue to think. So, Ockham concludes, fire is only a per accidens cause of heating, because it has an accidental part, namely, the accidental form of heat, which per se heats – whether separated from or conjoined to the fire. Likewise, a human substance is a per accidens cause of thinking, because it has an essential part, namely, an intellective soul (a substantial form), which per se thinks – whether separated from or conjoined to the body. Thus, it is true that ‘fires heat’ and ‘humans think’ – but only derivatively and by courtesy in a broad sense of ‘cause’ – because it is not the substances themselves that, strictly speaking, cause these effects; it is their non-identical accidental or essential parts (i.e., their accidental or substantial forms), which are the per se agents and power sources of these effects.
Now, one wishes Ockham would have given a different example here of a substantial form’s being a per se agent and power source, given the special nature of the intellective soul. Thus, one might wonder whether Ockham’s account of the per se causation of a substantial form only applies to the special case of the intellective soul in humans. However, Ockham elsewhere shows the universal scope of this distinction between per se and per accidens causation when he argues that all forms are per se agents and power sources:
But because form in creatures is the principle (ratio) of acting, form is truly said to be an agent … First, because something is truly an agent that when posited, an action can be posited, and when not posited, an action cannot be posited. But when the form is posited, the action can be posited, and when the form itself is removed when anything else is posited, the action cannot be posited. Therefore, the form itself is truly the agent. Second, because acting belongs to something primarily, and it does not belong primarily to the subject nor the aggregate from the form and subject, because then nothing would act unless the subject or the aggregate, which is manifestly false, because the form itself separated will be able to act. Third, because a separated accident truly acts, therefore, when it is conjoined, it truly acts. Fourth, because acting belongs to a subject through the form, therefore, it more truly belongs to the form itself.34
Notice two things here. First, Ockham connects the notion of something’s being ‘truly the agent’, with his earlier notion of an immediate and per se cause, which he identifies here with form. Second, Ockham again invokes his metaphysical separation thought experiment concerning a form’s ability to act when separated in order to argue that acting belongs primarily and more truly to the form itself, not to the subject nor the aggregate, since the form would still act even if it were separated and the composite destroyed.
And to emphasize that all forms, both substantial and accidental, are immediate, per se agents and power sources of effects – never composites in this way – Ockham concludes:
Thus, I say that a created form truly acts and truly generates and per se, and the supposit or even the composite does not generate nor act unless per accidens … And if it is said that ‘actions belong to supposits’, I say that this proposition is not found in philosophy, but it is said that ‘actions and real operations belong to singulars’, because nothing is real unless singular.35
Given Ockham’s reductionistic account of substance and his metaphysical separation thought experiment, it turns out that material substances are never per se causal agents and power sources. Rather, Ockham identifies the per se agent and power source with the material substance’s substantial form, which is an essential part of the substance but is not identical with the substance itself.36 Material substances, then, are essentially efficacious and powerful sine accidentibus, and yet, only by courtesy, per accidens, for it is the substantial form, not the substance, that is truly – and strictly speaking – essentially efficacious and powerful per se.
Given this result, it turns out that the real reason why all modal propositions concerning a material substance and its essential powers are necessarily true is due to the existence of the material substance’s substantial form. For since a material substance cannot exist without its substantial form existing, these propositions will always be true when the material substance exists, because its existence implies that its substantial form exists.
However, since Ockham thinks a substantial form can exist without the substance existing, at least by divine power, we are left with a rather peculiar result: all of a substance’s essential powers can still exist without the substance existing! For example, suppose God, by his absolute power, corrupted Bucephalus the horse by removing Bucephalus’s matter, but God still preserved Bucephalus’s equine substantial form, which is a material form spread out partes extra partes. Given that the power to neigh is a proprium of horses,37 it would follow that the power to neigh still exists, because this equine substantial form still exists.
Of course, this poor, equine substantial form couldn’t produce any acts of neighing to lament its metaphysical plight.38 But the power to neigh still exists, because the substantial form still exists. However, what the substantial form lacks is the necessary conditions and circumstances to elicit the act. Nevertheless, Ockham thinks the substantial form is naturally apt to elicit the act, even if the act is never elicited.39 But this is true more generally of any form and its power to φ, for the form would still be essentially powerful for φ-ing, even if it never produced an act of φ-ing.
4 Conclusion
The aim of this article has been to make a start on Ockham’s metaphysics of material substances’ essential powers. I have argued that Ockham thinks a material substance is essentially efficacious and powerful sine accidentibus. But given his reductionistic account of material substance, it turns out that a material substance is only essentially efficacious and powerful by courtesy, per accidens, as Ockham calls it, because the real source of a material substance’s action and power lies ‘underneath the hood’, so to speak, in one of its essential parts, namely, its substantial form, which acts per se. What is needed now is a deeper investigation into the nature and activities of these modally and causally rich substantial forms.
References
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Normore, C. G. “Ockham’s Metaphysics of Parts.” Journal of Philosophy 103 (2006), 737–754.
Pasnau, R. Metaphysical Themes 1274–1671 (Oxford, 2011).
Pasnau, R. “The Mind-Soul Problem.” In Mind, Cognition and Representation: The Tradition of Commentaries on Aristotle’s De Anima, eds. P. J. J. M. Bakker and J. M. M. H. Thijssen (Aldershot, 2007), 3–20.
Perler, D. “Ockham über die Seele und ihre Teile.” Recherches de théologie et philosophie médiévales 77 (2010), 313–350.
Robert, A. “L’explication causale selon Guillaume d’Ockham.” Quaestio 2 (2002), 241–266.
Stanton Edwards, S. Medieval Theories of Distinction, Dissertation (University of Pennsylvania, 1974).
Vucu, S. R. Henry of Ghent and John Duns Scotus on Self-Agency and Self-Motion: An Inquiry into the Medieval Metaphysics of Causal Powers, Dissertation (University of Toronto, 2018).
White, G. “Medieval Theories of Causation.” In The Stanford Encyclopedia of Philosophy, ed. E. N. Zalta, (Summer 2018 Edition), URL = <https://plato.stanford.edu/archives/sum2018/entries/causation-medieval/>.
White, G. “Ockham’s Real Distinction between Form and Matter.” Franciscan Studies 44 (1984), 211–225.
Wood, A. “Aquinas vs. Buridan on the Substance and Powers of the Soul.” In Questions on the Soul by John Buridan and Others. A Companion to John Buridan’s Philosophy of Mind, ed. G. Klima (Cham, Switzerland, 2017), 77–93.
Wood, A. “The Faculties of the Soul and Some Medieval Mind-Body Problems.” The Thomist: A Speculative Quarterly Review 75 (2011), 585–636.
I would like to thank Susan Brower-Toland and Can Laurens Löwe, who read and commented on previous versions of this paper, the participants of the 2018 Theories of Causal Powers in the Thirteenth and the Fourteenth Century workshop, and those at the Medieval Metaphysics Colloquium at the 2019 American Philosophical Association Central Division, who offered many helpful comments and suggestions on many of the ideas presented here, and finally, to the two anonymous reviewers for Vivarium for their incisive comments on a previous version of this paper.
See White, “Medieval Theories of Causation.”
See, e.g., Thomas Aquinas, Summa theologiae I, q. 77, 236–249. See also Clark, ‘The Cause of Causality’. Here I am only concerned with natural cases of efficient causation.
See, e.g., Heil, From an Ontological Point of View; Martin, The Mind in Nature; Heil, The Universe As We Find It.
See Cross, “Accidents”; Adams, Some Later Medieval Theories; Löwe, “Peter Auriol”; Löwe, “John Duns Scotus versus Thomas Aquinas”; Vucu, Henry of Ghent and John Duns Scotus.
To be more precise, the only things that exist are God, substantial forms, individual parcels of matter, certain accidental forms in the category of quality, and for theological reasons, a few primitive relations of union.
See William of Ockham, Quodlibet VI, q. 13, 633–634. See also Adams, “Was Ockham a Humean?”; Robert, “L’explication causale”; Pasnau, Metaphysical Themes, 537–538.
See William of Ockham, In II Sent. (Rep.), qq. 12–13, 20, 251–310, 425–447. See also Adams, “Ockham on the Soul”; Pasnau, “The Mind-Soul Problem”; King, “The Inner Cathedral”; Perler, “Ockham über die Seele”; Wood, “The Faculties”; De Boer, The Science of the Soul, 209–300; Wood, “Aquinas vs. Buridan”; Löwe, “Aristotle and John Buridan.”
For a contemporary account of the identity between a substance and its essential powers, see Marmodoro, “Power Mereology.”
Robert, “L’explication causale,” 250–253.
Robert, “L’explication causale,” 251–252: “Pour qu’une substance ait le pouvoir de causer tel effet sur telle autre substance, il faut que sa nature … soit telle qu’elle puisse causer cet effet. Mais, précisément, la nature d’une substance est identique à sa matière singulière et à ses formes substantielles. En effet, les accidents de la substance pourraient ne pas lui être attachés. L’ontologie hylémorphiste nous est désormais étrangère, mais l’exemple des artefacts nous parle encore. Si une clef a le pouvoir d’ouvrir telle porte, ce n’est pas seulement parce qu’elle a un pouvoir apéritif, mais surtout parce qu’elle est constituée de telle matière, c’est-à-dire d’une matière assez résistante pour ne pas se rompre dans la serrure, ainsi que d’une forme qui convient à celle de la serrure. A moins qu’elle n’ouvre cette porte que par hasard, il a fallu qu’elle soit conçue pour ouvrir cette porte (cause finale) et il a fallu un agent extérieur pour que l’action ait lieu (cause efficiente). Dans le cas des êtres naturels, la cause efficiente et la cause finale ne sont pas extrinsèques. On voit bien que, dans le paradigme aristotélicien, on peut expliquer une action causale sans faire appel à des accidents réels de la chose … Les pouvoirs causaux ne sont donc pas distincts de la cause, qu’elle soit une substance ou une qualité: dans le cas d’une substance, ce sont ses parties et dans le cas d’une qualité, c’est la qualité elle-même dans sa simplicité.”
Thomas Aquinas, Summa theologiae I, q. 77, a. 1, 236–237.
I say ‘among’, because some of a substance’s necessary powers are not strictly speaking propria, because they can belong to substances different in species, such as the powers of an animal that are common to both humans and horses. And by ‘necessary powers’, I mean to include all those powers necessarily correlated with a thing’s essence.
Thomas Aquinas, Summa theologiae I, q. 77, a. 1, ad 5, 237b: “Si accidens accipiatur secundum quod dividitur contra substantiam, sic nihil potest esse medium inter substantiam et accidens, quia dividuntur secundum affirmationem et negationem, scilicet secundum esse in subiecto et non esse in subiecto. Et hoc modo, cum potentia animae non sit eius essentia, oportet quod sit accidens, et est in secunda specie qualitatis. Si vero accipiatur accidens secundum quod ponitur unum quinque universalium, sic aliquid est medium inter substantiam et accidens. Quia ad substantiam pertinet quidquid est essentiale rei; non autem quidquid est extra essentiam, potest sic dici accidens, sed solum id quod non causatur ex principiis essentialibus speciei. Proprium enim non est de essentia rei, sed ex principiis essentialibus speciei causatur; unde medium est inter essentiam et accidens sic dictum. Et hoc modo potentiae animae possunt dici mediae inter substantiam et accidens, quasi proprietates animae naturales.” See also Summa theologiae I, q. 77, a. 6, 246b: “Unde manifestum est quod omnes potentiae animae, sive subiectum earum sit anima sola, sive compositum, fluunt ab essentia animae sicut a principio, quia iam dictum est quod accidens causatur a subiecto secundum quod est actu, et recipitur in eo inquantum est in potentia … Ad tertium dicendum quod emanatio propriorum accidentium a subiecto non est per aliquam transmutationem; sed per aliquam naturalem resultationem, sicut ex uno naturaliter aliud resultat, ut ex luce color.” For an examination of Aquinas’s causal language to describe the dependence of propria on their essence, see Vucu, Henry of Ghent and John Duns Scotus, 33–43. Can Laurens Löwe also provided to me a number of helpful insights about Aquinas’s use of causal language in these passages.
Ockham is not the first to reject Aquinas’s account; Henry of Ghent and John Duns Scotus had already rejected it. See Cross, “Accidents,” 133–146, and Vucu, Henry of Ghent and John Duns Scotus, 82–178.
See Stanton Edwards, Medieval Theories of Distinction.
William of Ockham, Quodlibet VI, q. 6, 60525–27: “Omnis res absoluta distincta loco et subiecto ab alia re absoluta potest per divinam potentiam existere, alia re absoluta destructa.” See Adams, “Ockham on Identity and Distinction,” and Boler, “Ockham’s Cleaver.”
William of Ockham, Summa logicae I, c. 24, 8055–72: “Quaelibet propositio affirmativa simpliciter, non aequivalens negativae, in qua praedicatur proprium, est aequivalens uni de possibili. Et hoc quia si non aequivaleret propositioni de possibili, illa posset per divinam potentiam esse falsa simul cum veritate propositionis in qua esse exsistere enuntiatur de subiecto. Unde quaelibet talis est contingens ‘substantia est quanta’, ‘omnis ignis est calidus’, ‘homo ridet’, et sic de aliis. Sed tales propositiones ‘omnis homo est susceptibilis disciplinae’, ‘omne corpus est mobile’, ‘omnis homo est risibilis’ necessariae sunt, sic quod non possunt esse falsae cum veritate propositionis in qua enuntiatur esse de subiecto, et aequivalent propositionibus de possibili. Sicut ista ‘omnis homo est risibilis’ aequivalet isti ‘omnis homo potest ridere’ … Ratio autem quare aliae propositiones sunt contingentes, ita quod possunt esse falsae simul cum veritate propositionis in qua enuntiatur esse de subiecto, est quia Deus potest omnem rem creatam facere sine alia, saltem priorem sine posteriore.” For the other senses in which Ockham says a ‘subject’ and an ‘attribute’ can be separated by divine power, see William of Ockham, Scriptum in I Sent. (Ord.), Prol., q. 3, 13610–1378; Quodlibet IV, q. 32, 45870–45993; Quodlibet V, q. 18, 55010–55386; Summa logicae III-3, c. 20, 677107–126.
William of Ockham, Summa logicae I, c. 24, 7925–26: “Deus non posset facere aliquem hominem exsistere quin ille esset risibilis.”
See William of Ockham, Summa logicae I, c. 18, 621–6590; Expositio Porphyrii, Prooemium, 15163–16198; c. 1, § 9, 271–2825; c. 2, § 15, 5235–5362; c. 4, 801–85162.
William of Ockham, Summa logicae I, c. 37, 10527–32: “Dicendum est igitur quod passio non est nisi quoddam praedicabile secundo modo dicendi per se de suo subiecto, et ideo omnis passio potest esse pars propositionis, et per consequens non est talis res extra. Ex quo sequitur quod non est impossibile subiectum esse in rerum natura sine sua passione, nec est impossibile passionem esse in rerum natura sine suo subiecto.” See also Expositio Porphyrii, c. 2, § 15, 5237–41: “Nam passio hominis quae dicitur ‘risibilis’ vel ‘risibilitas’ non est aliquid realiter exsistens in homine, cum non possit esse nec substantia nec accidens sicut inductive patet; sed tales proprietates hominis in communi non sunt nisi quaedam praedicabilia per se secundo modo de homine.” See also Scriptum in I Sent. (Ord.), d. 2, q. 4, 14213–1437; Summa logicae III-2, c. 7, 5151–519116; III-3, cc. 19–21, 6711–67951.
William of Ockham, Scriptum in I Sent. (Ord.), d. 2, q. 1, 2418–24: “Ad aliud per idem, quod haec est vera: homo et risibile sunt una res prout supponunt personaliter; et ita, quando supponunt personaliter, nihil verificatur de homine quod non verificetur de risibili et e converso; sed si supponant simpliciter, sic est haec falsa ‘homo et risibile sunt una res’, quia sunt distincti conceptus quorum unus non est alius; et isto modo verificantur istae: risibile est passio hominis, homo non est passio hominis.”
William of Ockham, Expositio Porphyrii, c. 4, 84128–85153: “Et ideo, sicut per istam ‘omnis homo potest ridere’, non denotatur quod aliqua alia res sit in homine sed sufficit quod possit esse, quia sufficit quod possit habere actum ridendi, eodem modo est de ista ‘omnis homo est risibilis’. Ex isto sequitur quod risibilitas non est aliqua res formaliter inhaerens homini, alia ab homine, sicut nec calefactivitas est aliqua alia res formaliter inhaerens calori; sed sicut calefactivitas non importat nisi principium calefactivum a quo potest esse calor, ita risibilitas nihil importat nisi hominem qui potest habere actum ridendi … Sic igitur patet quod calefactivitas non est aliqua res formaliter exsistens in calefactivo, et eadem ratione risibilitas non est aliqua res formaliter exsistens in homine, sed importat hominem qui potest habere actum ridendi.” Emphasis mine.
William of Ockham, Expositio Porphyrii, c. 3, 7828–7935: “Et ideo illud praedicatum ‘aptum natum navigare’, quamvis sit proprium hominis, et ‘animal’ per ipsum dividatur tamquam per differentiam non per se, quia tamen non complet definitionem indicantem substantiam rei, nec est pars definitionis exprimentis substantiam rei nec exprimit determinate unam partem rei, sed est quaedam habitudo eius, – hoc est, quoddam praedicabile connotans aliquid extrinsecum homini, scilicet actum navigandi.” See also Summa logicae I, c. 24, 7940–8054: “Non solum autem tenendum est quod proprium non semper est inhaerens subiecto cuius dicitur proprium, immo etiam tenendum est quod proprium non semper importat rem absolutam inhaerentem illi quod importatur per subiectum, sed aliquando importat rem distinctam ab illa re importata per subiectum et extrinsecum sibi. Et hoc aliquando affirmative, aliquando negative. Affirmative, sicut ‘calefactivum’, ‘creativum’ et huiusmodi. Unde ‘calefactivum’ non importat rem inhaerentem illi quod est calefactivum, sed importat rem quae produci potest ab eo; et hoc loquendo de primo subiecto ipsius. Similiter ‘creativum’ non importat rem inhaerentem Deo, sed importat rem natam produci a Deo. Negativae passiones sunt sicut ‘immortale’, ‘incorruptibile’, ‘immateriale’ et huiusmodi. Aliquando tamen propria important res inhaerentes vel natas esse inhaerentes illi quod importatur per subiectum, sicut huiusmodi passiones ‘dealbabile’, ‘alterabile’, ‘calefactibile’, ‘beatificabile’ et huiusmodi.”
Here I have only focused on one of Ockham’s reasons for rejecting Aquinas’s account of propria, namely, Ockham’s more general commitment to the real distinction and two things’ being ‘two-way separable’ from one another. For Ockham’s other reasons, such as considerations from parsimony, as well as his criticisms of Aquinas’s theological and philosophical arguments for the distinction between essence and power, see In II Sent. (Rep.), q. 20, 425–431. See also Adams, “Ockham on the Soul,” 62–65.
See William of Ockham, Summula I, c. 19, 2051–20898, and Quaestiones variae, q. 6, a. 2, 2071–219294. See also White, “Ockham’s Real Distinction”; Adams, William Ockham, 2: 633–669 (“The Metaphysical Structure of Composite Substances”); Cross, “Duns Scotus’s Anti-Reductionistic Account”; Cross, “Ockham on Part and Whole”; Normore, “Ockham’s Metaphysics of Parts”; Pasnau, Metaphysical Themes, 681–695.
William of Ockham, Summula I, c. 19, 20630–33: “Dicendum est igitur quod praeter partes quae sunt materia et forma non est alia tertia entitas distincta ab illis, sed est aliqua composita quae nec est una pars nec alia, ita quod illud compositum nec est materia nec forma sed simul et coniunctim materia et forma unitae.”
The phrase “normal and natural” comes from Adams, Some Later Medieval Theories, 249.
William of Ockham, In II Sent. (Rep.), q. 19, 4135–12: “Item, quando aliquis effectus sic se habet ad aliquam rem quod posita illa re potest poni effectus, illa res habet rationem causae respectu illius effectus immediate vel mediate. Hoc est satis evidens, quia effectus sufficienter dependet etc. Sed posita forma ignis cum calore potest alius ignis generari, et non posita forma ignis – etiam si calor ponitur – non potest generari. Sicut patet ad sensum si calor in igne separetur et agat in aquam, nunquam generabit ignem sed tantum calorem, igitur etc.”
On the distinction between an ‘immediate’ and ‘mediate’ cause, see William of Ockham, Expositio Physicorum II, c. 5, 28319–28427: “Sed intelligendum est quod causa efficiens dicitur dupliciter, quia quaedam est causa efficiens mediata, quaedam immediata. Causa efficiens immediata est illa quae potest sine hoc quod causet aliquod aliud ab illo effectu causare illum effectum; sicut ignis etsi non faceret aliquem alium effectum a calore, posset causare calorem. Causa efficiens mediata dicitur causa causae, quia scilicet causat aliquem effectum et ille effectus causat secundum effectum, ita quod si primus effectus remaneret sine causa priori, ita posset in effectum secundum sicut cum ea.”
Ockham goes on to offer a similar thought experiment on whether the substance is an immediate cause or a mediate, conserving cause of the effect, arguing in In II Sent. (Rep.), q. 19, 41313–4142: “Confirmatur per animam vegetativam, quia ipsa posita cum calore potest aliquid nutriri, et posito calore sine anima vegetativa non potest nutriri, igitur etc. Item, omne necessario requisitum naturaliter ad aliquem effectum vel est causa illius effectus mediata vel immediata. Igitur cum anima vegetativa necessario requiratur ad nutritionem, vel erit causa nutritionis mediata vel immediata. Si mediata, tunc est tantum causa conservans causam immediatam in esse. Sed si illa causa immediata conservetur ab alio, puta a Deo, destructa alia causa conservante nihilominus potest sequi effectus. Et per consequens destructa vegetativa adhuc posset esse nutritio alicuius naturaliter per solam formam accidentalem, quod falsum est. Igitur habet rationem causae immediatae.” Note, however, that Ockham does not explicitly say here in these texts whether he thinks the accident of heat is also an immediate, partial cause of the effect, because his point here is to distinguish between the substance being an immediate cause or only a mediate, conserving cause of the effect.
William of Ockham, In II Sent. (Rep.), q. 19, 41414–4152: “Substantia est frequenter principium immediatum effectivum actionis, et etiam accidens aliquando. Sed quando est sic et quando non, recurrendum est ut credo ad experientiam, quia si per experientiam possumus cognoscere quod sola substantia, posita in effectu et conservata, potest effectum causare sine omni accidente a parte principii elicitivi, ibi sola substantia est causa immediata effectus, concurrens tamen cum Deo. Si autem experiamur quod effectus potest causari a solo accidente sine substantia, tunc est accidens causa immediata, non substantia. Si autem non potest causari sine utroque, tunc utrumque est causa partialis respectu illius effectus. Et hoc est generaliter verum in omni actione naturali.”
See, e.g., William of Ockham, In IV Sent. (Rep.), q. 9, 1691–1706, and Quaestiones Physicorum, qq. 139–141, 7731–78382. See also Adams, Some Later Medieval Theories, 222–223.
William of Ockham, Scriptum in I Sent. (Ord.), d. 2, q. 10, 34421–34524: “Et ideo potest dici quod causa per accidens est illud quod agit per aliquid aliud ab eo; sed tale non est nisi subiectum vel totum habens partem qua agit. Et isto modo potest dici quod ignis per accidens calefacit, et eodem modo quod calidum per accidens calefacit. Et isto modo potest dici quod homo per accidens ratiocinatur; et similiter totum per accidens agit, quando actio sibi non convenit nisi mediante parte sua. Et ratio istius est quia illud dicitur per accidens competere alicui quo amoto nihil minus potest esse, sed igne destructo et reservato calore nihilominus poterit sequi calefactio, quia, sicut ostendetur in quarto, accidens actu separatum ita potest agere sicut coniunctum. Eodem modo illa actio quae competit homini mediante anima intellectiva poterit ita elici ab anima separata sicut a coniuncta; et ideo actio quae primo convenit parti, dicitur convenire toti per accidens, quia convenit sibi per aliud. Similiter actio primo competens accidenti dicitur convenire suo subiecto per accidens, quia per aliud. Et ita large accipiendo ‘per accidens’, secundum quod est idem quod ‘per aliud realiter distinctum’, sic potest concedi tam de subiecto accidentis quam de toto, cuius parti primo convenit actio, quod est agens per accidens, et eodem modo quod est causa per accidens. Sed causa per se est illud quod causat non per aliquid aliud realiter distinctum sed per se, ita quod ipso posito, omni alio circumscripto quod non est causa in alio genere causae, poterit sequi effectus. Et isto modo ipse calor est causa per se caloris, quia ipso posito, et omni alio amoto quod non habet rationem causae, poterit sequi calor in passo disposito et approximato; et ideo calor per se causat calorem, quia non per aliud. Et isto modo ipsa anima intellectiva per se causat intellectionem et volitionem, quia non per aliud, nisi secundum quod ly per notat circumstantiam causae partialis concurrentis.” This distinction is briefly discussed in Adams, William Ockham, 2: 767–770. For Ockham’s arguments that the subject of an accident is always equally as simple as the accident it receives, see In III Sent. (Rep.), q. 3, 11812–11916; In IV Sent. (Rep.), q. 9, 1631–16411; Quaestiones variae, q. 6, a. 2, 2071–219294. See also Cross, “Ockham on Part and Whole,” 160–166.
William of Ockham, Scriptum in I Sent. (Ord.), d. 5, q. 1, 2615–276: “Sed quia forma in creaturis est ratio agendi, vere dicitur forma esse agens … Tum quia illud quo posito potest poni actio, et quo non posito non potest poni actio, est vere agens. Sed posita forma potest poni actio, et ipsa amota quocumque alio posito, non potest poni actio. Igitur ipsa forma vere est agens. Tum quia agere convenit alicui primo, et non convenit primo subiecto nec aggregato ex forma et subiecto, quia tunc nihil posset agere nisi subiectum vel tale aggregatum, quod est manifeste falsum quia ipsa forma separata poterit agere. Tum quia accidens separatum vere agit, ergo quando est coniunctum vere aget. Tum quia agere competit subiecto per formam, ergo verius competet ipsi formae.”
William of Ockham, Scriptum in I Sent. (Ord.), d. 5, q. 1, 4712–19: “Sic dico quod forma creata vere agit et vere generat et per se, et suppositum vel etiam compositum non generat nec agit nisi per accidens … Et si dicatur quod ‘actiones sunt suppositorum’, dico quod haec propositio non invenitur in philosophia, sed dicitur quod ‘actiones et operationes reales sunt singularium’, quia nihil est reale nisi singulare.” Ockham’s claim here, and in the previous quoted passage – that created forms, not supposits nor composites, per se act – occurs within a larger discussion of the theological question of whether the divine action of generation belongs primarily to the divine essence or to a divine person, the Father. Therein Ockham discusses the ways creaturely causality is similar to, as well as different from, divine causality concerning to which things actions are primarily attributed. The claim ‘actions belong to supposits’, was made by Aquinas. It was later criticized by Henry of Ghent, John Duns Scotus, and Ockham himself concerning how to understand creaturely and divine causality. See Cross, “Accidents,” 133–146, and Adams, “The Metaphysics of the Trinity.” On Ockham’s definition of a suppositum, see, e.g., Quodlibet IV, q. 7, 32811–32938. Thanks to an anonymous referee for asking for clarification on how Ockham’s claims here about per se causation by created forms, not composites, fit within the wider context of this Trinitarian debate over divine causality.
This result is even seen all the way down in the elements. Ockham gives the example of water’s natural inclination for cooling, saying that water naturally cools itself, because “in aqua enim est principium intrinsecum activum inclinans contra calorem, in tantum quod si sibi dimittatur causat frigiditatem et destruit calorem” (Summula III, c. 33, 34330–33). In another passage, Ockham identifies the water’s active, intrinsic principle with the water’s own nature, by which he means the water’s substantial form. See Quodlibet III, q. 6, 22625–28: “Patet enim ad sensum quod aqua calefacta, si relinquatur naturae suae, redit ad frigiditatem; et illa frigiditas non potest causari ab aliquo nisi a forma substantiali aquae.” See also Quaestiones Physicorum, q. 117, 71596–716103; q. 124, 73230–35; q. 143, 78735–78849.
William of Ockham, Expositio Porphyrii, c. 4, 8024–25: “Et sic ‘esse risibile’ est homini naturale sicut equo est naturale ‘hinnibile’.”
This is, of course, assuming a logical contradiction would otherwise occur. But I will leave this modal logic exercise to the reader to work out.
See, e.g., Expositio Porphyrii, c. 4, 8020–24: “Sicut ‘esse risibile’ est proprium homini, quia solus homo est risibilis, et omnis homo est risibilis, et omni tempore est risibilis. Et si obiciatur quod homo non semper ridet actu, hoc dicit auctor non valere, quia quamvis homo non semper rideat, tamen semper est aptus natus ridere.” See also In III Sent. (Rep.), q. 4, 1328–11: “… accipiendo potentiam pro forma substantiali quae nata est elicere actum sentiendi, sed deficit aliqua dispositio accidentalis necessario requisita ad actum, et ideo non potest actus elici”; 13910–15: “Quod dico pro hominibus paralyticis et pro morientibus, ubi apparet quod primo una pars amittit actum tangendi, et post alia pars, in quibus partibus vere est anima sensitiva. Sed non possunt sentire, quia dispositio accidentalis quae necessario requiritur ad actum sentiendi deficit in illis et corrumpitur, non autem ipsa pars formae sensitivae.”