One fundamental philosophy of nature, or more specifically aphilosophy of change which is taken very seriously, is that of St. ThomasAquinas’s hylomorphism. The area of discussion is how these elementalsubstances are present in non-elemental substances. St. Thomas Aquinas holdsthe theory of virtual presence, which states that elemental substances’ powersaffect the non-elemental substance into which they are subsumed. This is a partof Aquinas’ doctrine of unicity.
There’s also another view in whichnon-elemental substances are composed of complete elemental and complete non-elementalsubstances, which are not merely virtually present. There are several reasonsfor a person to pick one idea over another, but we will find through ananalysis of Aquinas’s argument that the view which is contrary to Aquinas’svirtual presence and unicity of substances is preferential. In this paper, Iwill show that there is a plurality of substantial forms within a substance,contrary to Aquinas’s doctrine of unicity. We will arrive at this conclusionthrough the careful analysis of his argument’s premises. The contraryperspective is held specifically by the Franciscan School, so is not somethingparticularly new, but I hope to help to add to the ongoing dialogue. In orderto engage in discussion, an understanding of Aquinas’s view is essential.
The traditional view, or Aquinas’s doctrine of unicity, isone that has several issues. By rejection of this doctrine, we can solve theseproblems. First, empirical data that we have gathered with today’s advancementsin technology and science has shown that lower-order substances are notincorporated into higher-order substances such that they cease to exist asseparate, individual substances. Next, Aquinas shows that lower-ordersubstances go out of existence when subsumed by a higher-order substance, soboth the lower-order substance and its accidents no longer exist. Since thesubstances no longer exist, then all that can be subsumed into the higher-ordersubstance is prime matter, or pure potentiality. Because of this, there is noreason why the higher-order substance should take on qualitatively identicalaccidents to those that were actualized in the lower-order substance.
Anotherarea which cannot be easily explained using Aquinas’s doctrine is how integralparts of a complete substance seem to be able to exist on their own whenremoved from the complete substances of which they were a part and seem to becomplete substances. Aquinas’s unicity of substances doctrine is not the bestexplanation of the composition of substances. Therefore, a plurality ofsubstances within a substance is a better solution to the problem at hand.
There are some important terms that we also must take into consideration andunderstand well to engage better the argument that is being presented such assubsistence, form, accidents, subsumption, and actuality. These terms will bedefined in detail as needed throughout.Before we get into why one should accept a plurality ofsubstances and subsequently find Aquinas’s explanation lacking, we mustunderstand as thoroughly as we can the doctrine that Thomas Aquinas holds onthe unicity of substances.
There are two types of substances that Aquinasdefines. Higher-order substances are things which are usually larger and havemore complexity built into them, such as a human being, whereas lower-ordersubstances are often much simpler and less complex than the former. An exampleof a lower order substance is water. This is the beginning of a definition ofsubstances and is left as such to aid in clarity. Later, there will be a morein-depth investigation into substances.
When Aquinas talks about substances, he often refers to amixture of elements. This is especially significant regarding higher-ordersubstances. Elements are things like iron, gold, or oxygen, but they do nothave to be scientific elements. In fact, Aquinas understood them as things thatare the lowest-order kind of a complete, created material substance. Theseelements that Aquinas names are earth, air, fire, and water. He sees them asbeing substances which, when not part of or subsumed in a larger, higher-ordersubstance, are complete material substances (Aquinas, 2002). When lower-ordersubstances are subsumed in larger, higher-order substances, the result is amixture. A mixture of elements is best understood regarding the accidents orpowers that are given by the lower-order substance to the higher-ordersubstance.
Attributes from the higher-order substance are mixed withlower-order substances when the lower-order substance is subsumed (Decaen, 2000). When thinking of whathappens when we consume water, the elements hydrogen and oxygen, which arecombined into a compound, are being taken into or subsumed by a higher-ordersubstance, the human body.An important term that we must look to Aquinas to define iscomplete material substances. He gives us five essential aspects or parts tohelp determine and identify what a complete substance is.
First, it must besubsistent, or, in other words, it has to be in existence, actualized, and notjust potential or prime matter. Actuality can be understood through an exampleof a tree in the forest. The tree has accidents which are actualized, and itexists this way in reality.
This tree also has potentiality since it can be cutdown and divided into timber by something external to it, like a lumberjack.The tree also has the potential to grow bigger and taller, which is somethingthat is internal to the tree. Nothing can be purely potential except primematter, which underlies a substantial change within a substance, just like thecorruption, or death, into non-existence of the tree.
Since these substancesare not actualized in reality, they cannot exist within another completesubstance as an accident or material, substantial form under Aquinas’s view. Anotherintegral aspect that describes a complete substance is that it must beindividual. It must be concrete and unable to be applied to another in the waythat universals, like a car, can be used to describe particulars, such as a2018 Ford Shelby Mustang GT350.
A complete substance must also have itssubstantial form, meaning, that the substance’s matter must be unified andactualized by its form. A substance is not merely a collection of existingsubstances, and it cannot have the potency to be actualized by anothersubstance. It must also have its own end, and because of this, it must bealigned to its own perfection. To reach the end of its own perfection, it mustbe able to act through its own irreducible, causal powers for the sake of thatend. Finally, for a substance to be considered a complete substance, it musthave accidents within it (Aquinas, 2002).Elements, as were brought up earlier, are considered byAquinas to be complete substances.
These elements can be joined to formcompounds, such as alloys like steel, that may be used to make a sword.Contemporarily, elements are seen by some as atoms, molecules, and evensubatomic particles, all of which can be joined together to form largercompounds. While these two accounts of mixing differ, both the contemporaryview and Aquinas’s, hold that there are fundamental, physical, completesubstances that can come together in some way to form higher-order substances. Welook to Aquinas’s theory of how higher-order complete substances are created bythe joining of lower-order complete substances, which Aquinas defines aselements. These elements are what higher-order substances are composed of.Higher-order elements cannot come about except for the right proportion ofelements. If these elemental substances were to lose some of the elements thatare subsumed into them, they would not be able to exist and would corrupt backinto elements, just as non-elemental, higher-order substances would. Theseelements, however, would not have existed in the higher-order completesubstance which existed before, which is what Aquinas’s theory of virtualpresence explains.
With virtual presence, elements are subsumed intohigher-order substances and cease to exist. The matter that they were composedof is infused with the higher-order substances form, and consequently, isordered towards the higher-order substance’s end. Even though these substancesgo out of existence when this subsumption happens, Aquinas holds that theyremain virtually in some way through the powers they give. Therefore, for the sakeof the higher order substances acts and ends, the accidents, or powers, becomeaccidents of the higher-order substance, along with the accidents that thehigher-order substance already possessed (Storck, 2008). Certain accidents fromboth the higher-order substance and lower-order substance are then combined insuch a way that they are blended.
An example of when accidents are blended iswhen a substance which is subsumed has the accident of hyperhydration, such aswater. The higher-order substance has the accident of dehydration, like aperson stuck in a desert without water who would be severely lacking water. Theblending of these accidents will bring about the blended accident of hydrationwithin the human, the higher-order substance.
If we continue further into what Aquinas believes aboutsubstances and their parts, we must also give thought to the parts of asubstance and what constitutes a part. Examples of parts would be the organs ofan animal, such as the heart, lungs, or liver, which Aquinas would callintegral parts. Integral parts, as Aquinas defines them, share part of theirdefinition with the definition of complete material substances that he gives.These shared attributes help us to see why Aquinas’s definitions and argumentscontradict themselves, which allows for a better explanation of how substancesexist as a plurality of substances. These shared aspects are that both anintegral part and complete material substance must be subsistent, individual,and must have accidents inhering within them.
Integral parts also have a fewother qualifiers in their definition that are not included in the completematerial substance definition. One attribute is that an integral part is afunctional part of a higher-order substance. Another is that its matter has thesubstantial form of the higher-order substance, which means that an integralpart is ordered by the substantial form of the higher-order substance only toexercise the higher-order substance’s powers.
An integral part is also ordered tothe end of the higher-order substance as well. Therefore, the part is notordered to its end, but instead to the end of the substance of which it is apart of. The part might have retained or still have causal powers, but theywill be executed for the higher-order substance’s end only instead of its own(Koons, 2014). This is the point where Aquinas’s view leaves room for differentschools of thought on substances existing within other substances.Aquinas’s view shows that if one of these integral parts isremoved from the substance of which it is a part, like cutting off a dog’s ear,this part ceases to exist as it did before. The matter that was informed by theparts form then receives a new substantial form or forms, and the integral partceases to exist.
To explain why we call both an ear connected to a dog and onethat is separate from the dog’s head an ear in both cases, Aquinas uses thehomonymy principle (Pawl & Spencer, 2016). The homonymy principle whenapplied says that the ear that is connected to a dog is informed by the dog’ssubstantial form, and its ends are oriented to the ends of the higher-ordersubstance of which it is a part, namely the entire dog itself. The severed dogear would no longer have an attachment to the dog. Since the connected ear andthe severed ear are different in these ways, one accident of the attached ear,such as its pink color is quantitatively distinct from the accident of pinkcolor in the severed ear. These integral parts, as stated before aresubsistent, individual, and have accidents within them. This is different fromthose elements which are subsumed in higher-order substances.
Elements alsopre-exist the substance which they are subsumed into, and their matter is usedto generate substances. Integral parts, on the contrary, only come about or areproduced through dependency on the substances of which they originate. Sinceintegral parts, though they have the attributes as mentioned earlier, lack thecrucial features of having their own substantial form and their own end, theycannot be considered complete substances by Aquinas’s definition.
Several other issues can be raised against Aquinas’s view onsubstances and their parts that make his doctrine of unicity less plausiblethan a plurality of substances. One such objection is that his perspective onsubstances and their parts seems to be at odds with the empirical data obtainedabout the inclusion or fusion of lower-order substances into higher-ordersubstances. For example, we can now track subsumed substances, such as theoxygen, which attaches to the hemoglobin in our blood, or water molecules asthey move and disperse throughout the body. They are traced by their accidentsusing modern scientific techniques such as isotopic labeling, where themolecule has a radioactive isotope put into it (Allen, Evans, & Libourel,2014). The data is contrary to the Aquinas’s theory as shown above since hesays that once lower-order substances are subsumed, they no longer exist in thesame way as they did, but we can explicitly track them as they were before theywere incorporated. Aquinas’s virtual presence does not help his doctrine avoidthese problems that are caused by the empirical scientific data. While virtualpresence can explain why someone who is oxygenated has certain powers that theywould not have if they were oxygen deprived, it does not give us any clue as towhy we can track smaller substances through the larger higher-order substance.
One objection against this argument which helps solidify andsupport Aquinas’s theory of virtual presence states that the substance as itexisted before is no longer being tracked, but rather the matter that thesubstance was composed of as it moves throughout the higher order-substance isbeing traced. Aquinas says that when an elemental substance is subsumed into alarger higher-order substance, it no longer exists and ceases to be. The matterwhich it was formed then becomes some of the matter of the higher-ordersubstance, and the powers from the lower-order elemental substance are taken onby or given to the higher-order substance (Barnes, 2003).
This objection goesagainst Aquinas’s argument, which says that the matter that any substance afterit ceases to exist because of subsumption, would be pure potentiality or primematter, which is devoid of all actual properties and therefore would not beable to be tracked by tracking the properties through isotopic labeling. Itwould not even exist since it has no actualities.Another problem Aquinas’s doctrine encounters is that integralparts are able to exist, without losing their functionality, when they are nolonger incorporated in their original higher-order complete substance. A verysuitable example of this would be a human kidney. The kidney can be removed,even after the death of the human, which is a higher-order substance, and betransplanted later in another human. The kidney still retains all itsfunctionality, and so it fits the definition of a complete substance, asdefined by Aquinas himself. This evidence gives us good reason to dismiss thehomonymy principle, which was posited by Aquinas.Evaluation of Aquinas’s claim that lower-order substances goout of existence when they are subsumed into a higher-order substance leads toyet another problem for his doctrine of unicity.
Using Aquinas’s understandingof substances, one would have to say that elements are the matter whichhigher-order substances are generated from. This seems absurd since lower-ordersubstances cease to exist when subsumed. Therefore, they would not be able toprovide the matter from which something else could be made. This is distinctfrom one of the other complications that was brought to light before, sincethis issue is related to the matter itself, whereas the other was concernedwith the impossibility of tracking prime matter (Barnes, 2003).
Since the entiretyof a substance, its matter, and accidents cease to exist when subsumed by ahigher-order substance, another issue arises when trying to explain how theaccidents of the lower-order substance become those of the higher-ordersubstance, in a qualitative way. Accidents, as understood using Aquinas’sdoctrine, are qualitatively identical, and they go out of existence at the sametime as the lower-order substance. It follows that the higher-order substancecould not have qualitatively identical accidents to those that existed withinthe lower-order substance. Therefore, the only thing that seems like it couldbe subsumed into the higher order substance is prime matter (Feser, 2014).Again, this helps out a plurality of substances rather than a unicity.
Throughout thisessay, we have looked at various parts of Thomas Aquinas’s doctrine of unicityand his theory of virtual presence, and we have seen that there are severalproblems that his argument encounters which lead us to look to an alternativeview of a plurality of substances which I presented through my analysis. Theincompatibility between Aquinas’s doctrine and the empirical data which we cancollect, the problems with subsumption that do not allow for virtual presence,and the existence of integral parts as complete material substances whenremoved from the higher-order substance of which they were a part of areseveral issues which were discussed. These points allow for a rejection of his doctrine of unicity and givesa stable path of reasoning to adopt a plurality of substances within substancesexplanation. It is vital for one to undertake a critical analysis of argumentssince they can play a significant part in our understanding of how the worldexists. I hope that this essay accomplished helping in an endeavor tounderstand existence better through the addition of thoughtful and engagingdiscussion. References Allen, D.
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