Aquinas

Aquinas on Being, Existence, and Essence Ways of Speaking: Being, Existence, Essence, Definition 1. There are beings (ens): substances, properties, and so on. - Some beings are individual substances (ens per se); some are property instances (ens per accidens). Let s lea e it as a ope uestio hat ki d of ei g God is if God is e e a ei g . 2. Each being exists. - If a ei g did t e ist, it ould e a o -being. But no being is a non-being. - Existence is what distinguishes beings from non-beings. 3. For a being to exist is for an act of existing to belong to the being. - A ei g s e iste e dete i es that the being is. - Existence is an activity things do, not a passive state they endure. - This is h se o da su sta es atego ies: hu a , a i al, … a d p ope t ki ds (redness, rationality) are not beings: they do not act. 4. An essence (essentia) is what makes a thing the kind of thing it is. - A thi g s esse e dete i es what the thing is. - A thi g s esse e elo gs to the thi g fo all ti e. - Things of the same kind share the same essence. - It is possible for there to be exactly one thing with a particular essence. Background: Aquinas presupposes that there is a human-independent structure to reality, and that ea h thi g s esse e i ludes hate e disti guishes that thi g f o othe ki ds of thi g within this structure. (This makes Aquinas a kind of realist, rather than a constructivist.) This structure is pyramidal: things of the same species share the same essence; things of the same genus share part of their essence (because they are the same genus but different species); and so on. This structure is also hierarchical: ea h ele e t highe up i the p a id depe ds fo its e iste e o the e iste e of so e ele e t o e le el lo e i the p a id. - One corollary of the hierarchical structure of reality is that existence gives being to essence: there is no essence without some being to whom the essence belongs. For beings are the lo est le el of the p a id, a d if the e a e o ei gs ith a pa ti ula esse e, the e is nothing for the essence to be an essence of and thereby nothing to make the essence be. 5. A ei g s definition e p esses the ei g s esse e. - A ei g s defi itio is the a s e to the uestio , What ki d of thi g is it? - A real definition of a being locates the being within species, genus, and so on (up the pyramidal categories in the structure of reality). - Real definitions are ontological, determined by the structure of reality and thereby independent of human contingencies. - A nominal definition of a being uses language to predicates of the being its species, genus, and so on (up the pyramid). - Nominal definitions are linguistic, devised by humans and thereby dependent on human contingencies. Nicholaos Jones (2012) - If we were to decide to change the way we categorize beings, our decisions would change the nominal definitions of beings but leave unaltered the real definitions of beings. - Fo this easo , he A ui as speaks of a ei g s defi itio , he t pi all ea s its real definition: his interest is not how language shapes the way we view the structure of the world, but instead the structure of the world itself. If the structure of reality were not human-i depe de t, A ui as distinctions would collapse—as would his philosophical project. 6. The essence of a being is something the being either has or is. - Say a being has its esse e he the ei g s esse e does ot i lude e iste e. - Say a being is its esse e he the ei g s esse e is e iste e. - For each non-being, there is an essence that belongs to that non-being, but the non-being neither has nor is its essence: to have or be something requires existence. Propositions 7. There are no beings without essences. - Proof: Every being is the kind of thing it is, regardless of whether there happen to be other beings which are the same kind of thing. But an essence is the kind of thing a being is. Therefore, etc. Therefore, etc. 8. Some beings do not exist for all time. - Standard Example: You were born. Before you were born, you did not exist. Therefore, etc. - Relevant Article of Faith: Before God created the world (and the beings in it), there was nothing. Hence, there was a time at which created beings did not exist, namely, before God created the world. Therefore, etc. 9. If a being does not exist for all time, its essence does not include existence. - Proof: Suppose that x is a being that does not exist for all time. Since x is a being, x has an essence. Suppose, for reductio, that s esse e i ludes e iste e. “i e a ei g s esse e elo gs to it fo all ti e, it follo s that s e iste e elo gs to it for all time. But this is just to say that x exists for all time, contrary to the initial supposition. Therefore, etc. - Beings that do not exist for all time have their essence, but they are not identical to their essences. 10. The essence of some beings does not include existence. - This follows from the preceding two propositions. 11. Although all beings exist, existence (existing being) is not category of beings. - Proof: Suppose existence is a category of ei gs. The ea h ei g s esse e i ludes existence. But the essence of some beings does not include existence. Therefore, etc. - This ea s that the p a idal st u tu e of ealit does ot i lude a atego e isti g thi g under which beings fall, even though all beings are similar by virtue of being existing things. - This also ea s that the disti tio et ee esse es that do ot i lude e iste e a d esse es that a e ide ti al to e iste e is e hausti e: the e is o oo fo a esse e that includes, but is not identical to, existe e. Fo if a ei g s esse e e e to i lude e iste e without being identical to existence, existence would be a category of that being. But existence is not a category of any being. Therefore, etc. Nicholaos Jones (2012) Speculation If there is a being whose essence is identical to existence, then there is no other being whose essence is also identical to existence. - Proof: If there were two beings, such that the essence of each were identical to existence, then those two beings would be the same kind of beings—namely, the kind of beings whose essence is identical to existence. If there is such a kind, then existence is a category. But existence is not a category (see proposition 11). Therefore, etc. - Note: I a ot su e hethe this is A ui as a gu e t. I also a ot sure whether it is sound elati e to A ui as s ste dou t o e s the se o d p e ise i the a gu e t . Some Questions Aquinas maintains (in reading we have not yet covered) that God s esse e is ide ti al to God s ei g. 1. If God s esse e is ide ti al to e iste e, the God s esse e i ludes existence. This entails that God exists for all time (via #9). What does it mean for God to exist for all time? 2. If God s esse e is ide ti al to e iste e, then since all other beings have existence (or else they ould t e ei gs , hat is God s elatio to othe ei gs? Is God s esse e so eho pa t of these other beings? Are these other beings the same as God? 3. Aquinas says that natural reason can lead us to know whether God exists without showing us what God is—that is, ithout sho i g us God s esse e “T.I.Q .A . But if God s esse e is ide ti al to e iste e, ho ould e k o God s e iste e ithout also k o i g God s esse e? 4. Aquinas says that natural reason leads us to know what necessarily belongs to God even though it does ot sho us God s esse e “T.I.Q .A . Is that hi h e essa il elo gs to God the sa e as God s esse e? If so, ho ould e k o o e ithout k o i g the othe ? Nicholaos Jones (2012) Aquinas on Causation Aquinas takes understanding something to consist in understanding why something is the way it is rather than some other way. - When we give an account of why something is one way rather than some other way, we are giving a contrastive explanation. - A contrastive explanation is an a s e to the uestio Wh p athe tha ? Aquinas supposes that we understand why something is one way rather than another by identifying its cause. - The a s e to Wh p athe tha ? is because x causes p instead of q. Aquinas identifies four kinds of cause, each of which corresponds to a different way of understanding why something is one way rather than another. - Ea h ki d of ause, a o di gl , p o ides a a s e to a diffe e t ki d of Wh p athe tha ? uestio . Material Cause The ans e to Wh is this ei g this individual rather than that individual? has the form because this being has this matter rather than that matter. - The matter of a being is the material cause of the being. - The material cause of a being is that which makes that being numerically distinct from other beings. o Each individual being has its material cause for all time. - The effect of a material cause is being a particular individual. Formal Cause The a s e to Wh is this being able to do this kind of activity rather than that kind of activity? has the form because this being has this essence rather than that essence. - The essence of a being is the formal cause of that being. - The formal cause of a being is that which makes that being the kind of being it is. o Beings of the same kind have the same formal cause. o Each individual being has its formal cause for all time. - A ei g s fo al ause dete i es its apa ities—the kind of functions and activities it is able to perform. - The effect of a formal cause is membership in a species. Agent Cause The a s e to Wh does this ei g exist rather than not exist? has exactly one of two forms: (1) e ause the eing’s existen e belongs to the eing’s essen e; or (2) e ause the eing’s existen e is produced by some being. - I ase , the e pla atio appeals to the ei g s formal cause. o This is o su p ise. “i e e iste e, fo A ui as, is a ki d of a ti it , the uestio Wh does this ei g e ist athe tha ot e ist? is a spe ial ase of the uestio Wh is this bei g a le to do this ki d of a ti it athe tha that ki d of a ti it ? —substitute e isti g as the ki d of a ti it . - I ase , the e pla atio appeals to the ei g s agent cause. - The agent cause of a being is that which makes the being exist. Nicholaos Jones (2012) No being is its own agent cause, because causes must precede their effects (there is no backwards agent causation) and nothing can precede its own existence. The effect of an agent cause is that which the agent cause produces. There are two possible ways an agent cause can produce its effects, by nature and by intelligence. o An agent cause produces its effects by nature when its essence determines its activity. o An agent cause produces its effects by intelligence when the goals it seeks to achieve determine its activity. Only agent causes with desires can produce effects by intelligence, because only beings with desires seek to achieve goals—beings without intelligence might, in fact, achieve goals, but they do not seek to achieve those goals. o - - Final Cause The a s e to the uestio Wh does the age t ause p odu e this kind of being rather than that kind of being? has one of two forms: (1) because the essence of the agent cause is to produce beings of this kind rather than that kind; or (2) because the agent cause sought/desired a being with the ability to perform this activity/function rather than that activity/function. - I ase , the e pla atio appeals to the age t ause s fo al ause, and the agent cause acts by nature. - In case (2), the e pla atio appeals to the age t s desi es a d pu poses, a d the age t ause acts by intelligence. - The function/activity sought by an agent cause in producing a being by intelligence is the ei g s final cause. - The final cause of a being is that for which the being is made to exist (or, in shorthand terminology, the purpose of the being). o Because the final cause is an ability to perform a function/activity of some sort, and because the formal cause of a being determines its functional/active capacities, a ei g s fo al ause is a guide to its fi al ause. - The effe t of a fi al ause is the pu pose of a ei g the goal fo hi h the ei g s age t ause produces the being). - - Note 1: A ui as a gues that a a s e to the uestio Wh does the age t ause p odu e this kind of being rather than that kind of being? ust ulti ately appeal to some final cause (as with case (2)). For an answer with the form of case (1), appealing to an act by nature, leads to the question of why the agent cause has this essence rather than essence. The answer to this question is given by the formal cause of the agent cause. Since formal causes are beings (if they did not exist, they could not be causes), this answer leads to the question of why this formal cause exists rather than not exists. The answer to this question is given by an agent cause of the formal cause. This answer leads to the question of why the agent cause produces this essence rather than that essence. If the answer to this question appeals to the essence of the agent cause, we are off on a regress of explanation-seeking questions. Since Aquinas denies that any such regress is explanatory, he infers that, at some point, the explanation must appeal to an agent cause acting by intelligence. Note 2: Aquinas denies that an answer with the form of case (2) leads to a regress of explanation-seeki g uestio s. Fo the a s e to the uestio Wh does the age t ause desire a being with the ability to perform this activity/function rather than that activity/function? is e ause that is the agent ause’s hoi e. Choices, for Aquinas, are uncaused, because they are free. Nicholaos Jones (2012) - Note 3: The a s e to the uestio Wh does the age t ause p odu e this particular substance rather than that particular substance? has the fo because the agent cause acted upon this matter rather than that matter. This explanation, of the individuality of a substance, appeals to material cause. Aquinas distinguishes between intrinsic and extrinsic causes. A cause is intrinsic to a being if the cause is feature possessed by the being. o Material and formal causes are intrinsic causes: the material cause is the matter of the being; the formal cause is the essence of the being. - A cause is extrinsic to a being if the cause is a feature possessed by some other being. o Agent and final causes are extrinsic causes: the agent cause is the activity of some other being; the final cause is the goal sought by some other being. - Intrinsic causes provide understanding of a being in relation to itself: they identify what the being is (matter+form). - Extrinsic causes provide understanding of a being in relation to other beings: they identify how the being fits among other beings. Realism and Causation The le tu e otes o Bei g, E iste e, a d Esse e e a k that A ui as is a ealist o e i g the hierarchical structure of the world. The central claim of this realism is that the essence of each being exists independently of humans. This claim is compatible with the language we use to describe essences being dependent on humans. But once we fix the meaning of the terms in our language, nominal definitions of essences express the real (human-independent) definitions of beings. (Of course, if we change the ea i g of ou te s, e ha ge the o i al defi itio s; hat e do t ha ge is the eal definitions— e do t ha ge the esse es. - - Nominalism is the thesis that all definitions are nominal definitions. Constructivism (or constructionism) is the thesis that human beliefs and/or human languages imposes structure onto the world, and that the world itself has no structure independent of our doxastic and linguistic constructions. Constructivism is a kind of nominalism, since it denies that there are human-independent essences that could be defined. Constructivists differ over whether we perform impositions of structure by nature (think David Hume) or by intelligence thi k al ost a post ode philosophe . Transcendental Realism is the thesis that humans impose structure onto the world, that we perform this imposition by nature, and that we cannot know whether the world itself has a structure independent of our conceptual constructions. A ui as o it e t to ealis see s to follo f o his o it ent to the complete intelligibility of existence. This is a commitment to the claim that anything which exists can be understood (if not by us, then with beings of superior intelligence). It is akin to what Leibniz will later endorse as the Principle of Sufficient Reason: There is a sufficient reason for anything that is. “u stitute e pla atio o ause fo suffi ie t easo , a d Lei iz s p i iple see s to e p ess A ui as o it e t. Aquinas takes there to be four possible ways to completely explain something that is: identify its material cause, if it has one (some beings, like angels, do not have material causes); identify its formal cause; identify its agent cause, if it has one; identify its final cause, if it has one. For Aquinas, to say that the world is completely intelligible is to say that each of these causes exist for all things that exist—that Nicholaos Jones (2012) is, that any material being whose essence does not include existence has material, formal, agent, and final causes; that any immaterial being whose essence does not include existence has formal, agent, and final causes; and that any being whose essence includes existence has a formal cause. (While Aquinas ai tai s that e a ot u de sta d God s fo al ause, it does ot follo that God s fo al ause is unintelligible, provided at least that God understands it.) Aquinas believes that we have some evidence that at least some of the world is intelligible. For example, we observe that sharks can swim unassisted for very long periods under water but humans cannot. This involves observing that a class of beings share a particular capacity, and that this capacity sets them apart from some other beings. We also observe that humans can walk upright unassisted but sharks cannot. This involves observing that a class of beings shares a particular capacity, and that this capacity sets them apart from some other beings. If we combine these two observations, we learn that there are two classes of beings, such that members of each class share a capacity that members of the other class lack. Aquinas takes pointing to these different capacities to explain a difference between sharks and humans. Similar evidence, evidence regarding other ways of explaining things, as well as the absence of reason to suppose that there is something that could not be explained, suppo t A ui as o it e t to the complete intelligibility of the world. (This commitment also might receive support f o A ui as articles of faith.) If we define a formal cause to be a set of capacities that sets a class of beings off from other beings, and if we suppose that the capacities which some beings have do not depend upon humans, it follows that there are formal causes which exist independently of human beliefs and human language. The commitment to the complete intelligibility of the world entails that there are formal causes for everything that exists, and if we suppose that the capacities which beings have are independent of hu a eliefs a d hu a la guage, A ui as ealis a out esse es follo s. This all supposes, of course, that capacities of sharks, trees, and other beings are independent of human beliefs and human language—that, no matter what our beliefs or the way we choose to talk about sharks, sharks are able to swim unassisted for very long periods under water. Nicholaos Jones (2012) Aquinas on Being and Goodness I “T I.Q .A , A ui as lai s that Good ess a d ei g eall the sa e, a d diffe o l i idea. He offers the following argument: 1. 2. 3. 4. 5. 6. The essence of goodness consists in being desirable in some way. Something is desirable only insofar as it is perfect. Something is perfect insofar as it is actual. Existence makes all things actual. Hence, something is perfect insofar as it exists (from 3,4). Therefore, goodness and being are really the same (from 1,2,5). From #1 and #2, it follows that the essence of goodness is being perfect; from this and #5, it follows that the essence of goodness is existing (being). He offers #1 as an explanation for why Aristotle says that Good ess is hat all desi e, a d he suppo ts # ith the lai all desi e thei o pe fe tio . There seem to be several difficulties with the argument. First, establishing that the essence of goodness is ei g see s to fall sho t of sho i g that good ess a d ei g a e eall the sa e. “e o d, the premises seem to be questionable if not outright false. The support for #2 fails, because it apparently does not rule out the possibility things might also desire non-perfect things. And #1 seems to be false, because surely some desirable things—the desire for genocide among some racist groups, for example—are not good. The principle of charity demands that we not attribute an obviously flawed and defective argument to another person if there is an alternative interpretation of their argument which renders it less obviously flawed or defective. The a to sea h fo a alte ati e i te p etatio , i A ui as ase, is to pause to consider what he means te s like good ess a d desi a le —we might find, for example, that the argument is flawed only to the extent that we saddle him with our contemporary understanding of these terms. (An argument that rejects a claim based upon a misinterpretation of the meaning of the claim is a kind of straw man fallacy, regardless of whether the misinterpretation is intentional.) Really the same e sus different in idea Scholars tend to agree that Aqui as disti tio et ee really the same and different in idea closely corresponds to our contemporary distinction between the reference of a term and the sense of a term. - the reference of a term is that which the term designates/picks out in the world the sense of a term is the thought-content which the term expresses It is possible for a term to have a sense but no reference—fo e a ple, the se se of Od sseus is legendary Greek hero who endured such-and-such adventures in the Mediterranean, but (assuming Odysseus is fi tio al , Od sseus has o efe e t; a d the se se of elestial od fu thest f o the su is body in space which is such that there is no other body with a larger distance from the sun, but si e the e is o su h od , the te elestial od fu thest f o the su has o efe e e.1 1 I use quotation marks to refer to terms, italics to refer to senses of terms, regular font to refer to references of terms. Sometimes quotation marks mark a quotation, and italics emphasize. Use should be clear by context. Nicholaos Jones (2012) It is also possible for terms with different senses to have the same reference. The classic examples here a e the te s o i g sta a d e e i g sta . The se se of o i g sta is bright planet visible during sunrise; of e e i g sta , first planet visible after sunset. As it turns out, the reference of these terms is identical: the planet Venus. If e assu e that eall the sa e Aquinas means same in reference, and that b diffe e t i idea he means different in sense, the A ui as thesis i “T I.Q .A is a out the terms good ess a d ei g, a d e a efo ulate that thesis as: “T I.Q .A : The te s good ess a d ei g ha e the sa e efe e e ut diffe e t se ses. If we do this, then we need to figure out what Aquinas takes to be the sense and reference of good ess a d ei g. Our prior lecture indicates that, according to Aquinas, the se se of ei g, that which one thinks of something when one thinks of it as being, is existing—being identical to, or participating in, the act of existing; a d the efe e e of ei g is an actualization of potentiality: when a potential is actualized, that which was in potential comes to be in existence. Aquinas says that the essence of good is being in some way desirable. But understanding what he means here, and why he ight thi k that the efe e e of good that to hi h good efe s is a tualizatio of a pote tial, requires some background from Aristotle. Goodness, Desire, and Perfection In the Eudaimonian Ethics and Nicomachean Ethics, Aristotle investigates the nature of goodness. He otes that the efe e t of good diffe s i diffe e t ki ds of ei gs. For example, goodness in an axe (what it is to be a good axe) differs from goodness in an eyeball (what it is to be a good eyeball). The reason for this difference, according to Aristotle, is that different kinds of beings have different essences. The essence of an axe, for example, involves a potential for cutting, while the essence of an eyeball involves a potential for seeing. A good axe, accordingly, is an axe that is sharp (so that it actually cuts), while a good eyeball is an eyeball with sight (so that it actually sees). Eyeballs could, one might suppose, be used for cutting—if they were properly sharpened and hardened; but an eyeball that cuts would not be a good eyeball unless it also sees—it would be good-for-cutting despite failing to be good simpliciter. A o di gl , fo A istotle, a ei g s good ess o sists i the actualization of the potentialities it has by virtue of its distinctive essence. If we refer to these potentialities as specific potentialities, the relevant se se of good is actualization of species potentials. In his works on biology, Aristotle argues that different kinds of beings have different potentials by virtue of having different essences. The essence of a human, for example, is rational animal: rationality involves potentials for scientific understanding (via theoretical reasoning) and emotional harmony (via practical reasoning); animality involves potentials for perceiving (seeing, hearing, etc), nourishing (ingesting, digesting, excreting, etc), and growing. All humans have these potentials, by virtue of having the essence rational animal, even if some humans do not, or cannot, actualize these potentials. These potentials distinguish humans from other kinds of animals, insofar as other animals lack (say) rationality; and they distinguish humans from plants, insofar as plants lack both rationality and perception. These conclusions allo A istotle to e plai h the efe e t of good diffe s i diffe e t ki ds of ei gs: since different kinds of beings have different species potentials by virtue of having different essences, Nicholaos Jones (2012) and since the se se of good is actualization of species potentials, that to which good refers differs for different species.2 A ui as ag ees ith all of this: the efe e e of good is elati e to a ei g s esse e, a d the se se of good is actualization of species potentials. This has two salient consequences. First, insofar as potentials are human-independent a d the a e, if A ui as s ealis a out esse es is o e t , whether a being is good is an objective matter; and although goodness is relative, it is not relative to personal belief, culture, or anything else that human choices can alter—it is relative to essence. So Aquinas rejects self- and cultural- relativism. Second, insofar as the desires and wants of beings do not determine which potentials are distinctive of their (or other beings') essence, goodness is independent of desires and wants. So Aquinas also rejects ethical subjectivism. This second consequence, that goodness is independent of desires, seems to conflict with A ui as lai that the esse e of good ess o sists i [ ei g] i so e a desi a le. Given the sense Aquinas as i es to good, the p i iple of ha it suggests that e atte pt to fi d so e se se of desi a le other than worthy of being desired or desired by something. He e s a suggestio : Aquinas means desi a le i the se se of tending toward ends distinctive of one's essence. Desires typically direct action toward achieving some end (that which is desired). If we understand "directing action" in an active sense, as an inclination or tendency to act, we can understand desire as a tending toward an end. If we take "desirable" to refer to desires directed toward ends things have by virtue of their distinctive essence, then being desirable is being tended toward ends distinctive of one's essence. Let s see the e te t to hi h this i te p etatio of being desi a le akes A ui as a gu e t i telligi le. The essence of a being, what makes the being the kind of being it is, makes certain goals available to the being and others unavailable. If we follow Aristotle (and Aquinas) in taking the essence of humans to be rational animal, humans aim at understanding (by doing science), emotional balance (by practicing virtue), perceiving (by touching, tasting, etc), nutrition (by eating), growth (by sexual intercourse), and so on. Non-rational animals can aim at some of these goals—perception, growth—but not others— understanding, emotional balance, e ause thei esse e i ol es fe e pote tials tha a hu a s essence. (Aquinas, following Aristotle and then-available biological theory, takes potentials to be nested in a kind of Porphyrian Tree.) If good humans are humans who actualize potentials associated with rationality, then the essence of human goodness consists in tending in some way toward being rational. If we generalize, from good human to good thing, and if we take the essence of goodness to be that which makes good things good, we obtain Aquina's first premise for the co-referentiality of "good" and "being," namely, that the essence of goodness consists in being desirable in some way. Understanding Aquinas' second premise, that something is desirable only insofar as it is perfect, requires understanding what he means by "perfect." Assuming that perfection is a superlative kind of goodness, then since being good is actualizing species potential, it follows that being perfect is fully actualizing such potentials. If there are degrees of actualization, such that something can actualize a potential without fully actualizing that potential (and Aquinas thinks this is possible), it follows that beings are more or less perfect in proportion to how much they actualize their species potential. Our interpretive efforts thus far offer the following "translation manual" for Aquinas' terminology: 2 A othe 30-31). a to put this: good is a att i uti e adje ti e athe tha a p edi ati e adje ti e. See Davies (2011: Nicholaos Jones (2012) essence of goodness  that which makes good things good x is desirable  x tends toward ends associated with its species potential x is perfect  x fully actualizes its species potential Let's re-write Aquinas' argument using this translation manual. 1. The essence of goodness consists in being desirable in some way. 2. Something is desirable only insofar as it is perfect. 3. Something is perfect insofar as it is actual. 4. Existence makes all things actual. 5. Hence, something is perfect insofar as it exists. 6. Therefore, goodness and being are really the same. 1.* That which makes good things good is their tending in some way toward ends associated with their species potential. 2.* Things tend toward ends associated with their species potential only to the extent that they actualize that potential. 3.* Things actualize their species potential to the extent that they are actual. 4.* Existence causes things to be actual. 5.* Hence, things actualize their species potential to the extent that they exist. 6.* The efo e, good a d ei g ha e the sa e reference. With Aquinas' argument explicated, we can turn to assessing its validity. That the conclusion follows from the premises is not entirely clear, primarily because many of the premises identify functional relationships between properties. The second premise treats actualization of potential as a function of progress toward an end; the third, actuality as a function of potential actualization; the fourth existence as a function of potential actualization. We can notice, however, that when one thing is a function of another, the former occurs if and only if the latter does. If we notice, further, that something is good if it actualizes the essence of goodness to at least some extent, we can infer the following corollaries: 1.' A thing is good iff it tends in some way toward ends associated with its species potential. 2.' A thing tends toward ends associated with its species potential iff it actualizes its species potential. 3.' A thing actualizes its species potential iff it is actual. 4.' A thing is actual iff it exists. 5.' Hence, a thing actualizes its species potential iff it exists. 6.' Therefore, "good" and "being" have the same reference. Premises 1' – 5' entail that a thing is good iff it exists, and since to exist just is to have being (participate in the act of existing), it follows that a thing is good iff it has being. Something is referent of "good," accordingly, iff it is a referent of "being." And this is what Aquinas aims to prove. The third premise in this (reconstructed) argument is open to challenge. For while it is clear that only actual things can actualize species potential (since things lack actuality thereby lack actuality of species potential), it is not clear that actual things must actualize their species potential. In particular, if there are actual things of pure potential, then some actual things do not actualize their species potential to any extent whatsoever. The fourth, too, is open to a similar challenge. For while it is clear that whatever is actual exists (because whatever is actual is), it is not clear that whatever exists must be actual. In particular, if there are pure potentials, then these potentials exist (by virtue of being something) even though they are not actual (by virtue of being pure potentials). Nicholaos Jones (2012) Aquinas most likely rejects the possibility of pure potentials on the basis of his empiricism, according to which all of our knowledge must be grounded in empirically-accessible information. If only that which is actual is empirically accessible, it follows that there is no way to know whether there are pure potentialities – and if this is the case, it seems that postulating them in one's metaphysical framework is otioise. There is, of course, another premise in Aquinas' (reconstructed) argument open to challenge, namely, the fifth. For if Aquinas' realism about essences is mistaken, there are no such things as species potentials and so beings never actualize such things. Since it is obvious that beings exist, it follows that denying that there are essences entails denying Aquinas' fifth premise. The debate here centers on whether Aquinas' realism is correct—whether, as we say nowadays, there are "natural kinds." This debate continues today; you can check out the Stanford Encyclopedia of Philosophy's entry on Natural Kinds http://plato.stanford.edu/entries/natural-kinds/ for more information. (In Aquinas' day, the debate was between realists and so-called nominalists.) Nicholaos Jones (2012) Aquinas' Five Ways3 Orders of Efficient Causation Aquinas, following the ancient and medieval philosophical tradition inspired by Aristotle and transmitted through Islamic philosophers, distinguishes among orders of efficient causation. An order of causation is a kind of causal series. For Aquinas, there are two such kinds: per se and per accidens. A series of efficient causes is ordered per se iff w being F causes x to be G, x being G causes y to be H, y being H auses …. The salie t featu e of this o de i g is that the a i hi h so ethi g is ade to be as an effect is identical to the way in which that something acts as cause. The paradigm case of a per se ordering of efficient causes is a hand pushing a stick, which pushes a stone: the hand moving causes the stick to be moved, and the stick moving causes the stone to be moved. Not all series of efficient causes are ordered per se. When they are not, they are said to be ordered per accidens: w being F causes x to be G, x being H causes y to be I, y being J auses …. The salie t featu e of this ordering is that the way in which something is made to be as an effect is different from the way in which that something acts as cause. The paradigm case of a per accidens ordering of efficient causes is Abraham begetting Isaac, who in turn begets Jacob: Abraham's copulating causes Isaac to be born, and Isaac's copulating causes Jacob to be born. The generic properties of per se causal orders differ from those of per accidens causal orders. Two differences are relevant to understanding Aquinas' Five Ways. First, the members of per se orders, but not per accidens orders, "act together at the same time." The members of any causal series are particular instances of properties: this particular pushing, this particular copulating, and so on. And no particular instantiation of a property persists through time. So x being G can be caused by w being F and also cause y to be H only if x being G is caused and causes at the same time. The same is not true for members of per accidens causal series: Isaac, for example, can be born at one time and yet copulate at some later time. Hence, while per accidens causal series are chronological, per se causal series are not— the members of such series occur simultaneously—causes in per se orders precede their effects logically but not temporally. This atemporality of per se causal series entails a second important difference between the two orders of efficient causation, namely, that causal relations are transitive in per se orders but not per accidens orders. In a per se causal series, if w being F causes x to be G and x being G causes y to be H, then w being F causes y to be H: since the hand moves the stick and the stick moves the stone, the hand moves the stone. Not so with per accidens orders: even though Abraham's copulating causes Isaac to be born and Isaac's copulating causes Jacob to be born, Abraham's copulating does not cause Jacob to be born. The Nature of Aquinas' Proofs Aquinas's aim in proving the existence of God is to infer from empirically accessible features of the world to God's existence. There are two competing approaches to interpreting the nature of the inference Aquinas wants to make. One interpretation maintains that Aquinas' inferences are deductive: such-andsuch features are the case only if God exists. A competing interpretation maintains that they are 3 These notes are heavily indebted to Patterson Brown's "Infinite Causal Regression," Philosophical Review 75 (1966): 510-525. Nicholaos Jones (2012) explanatory: such-and-such features are intelligible if God exists. Call these the deductivist and explanationist interpretations of Aquinas' Five Ways, respectively. If the deductivist interpretation is correct, then Aquinas' arguments succeed if, and only if, their premises are true and their common conclusion (that God exists) must be true if the premises are true; and the reason to accept the conclusion is that the premises deductively entail it. (For logicians, iff the arguments are sound.) According to the Principle of Charity, we should interpret Aquinas' inferences as deductive only if either this interpretation makes his arguments good ones or there is no alternative interpretation which makes his arguments better than the deductivist interpretation does. If the explanationist interpretation is correct, then Aquinas' arguments succeed if, and only if, their premises are true and their common conclusion (that God exists), if it were true, would be the best (or only) explanation of the truth of the premises; and the reason to accept the conclusion is that it would best explain the premises. (This is known as inference to the best explanation; importantly, this is not a question-begging argument, because whether the truth of the conclusion would explain the premises is independent of whether the conclusion is true.) Whether one claim explains another depends, in part, on what counts as an explanation, and on what makes one explanation better than another. Aquinas subscribes to Aristotle's account of explanation: P explains Q just if P deductively entails Q and P is a "first principle"—that is, a claim the truth of which requires no explanation. (One way a claim can require no explanation is by being necessarily true. Note that a claim can be necessarily true even if it is possible to doubt whether it is true—or, as Aquinas says in ST I.2.1, a thing can be self-evident in itself but not to us.) Hence, according to the explanationist interpretation, Aquinas' arguments succeed if: their premises are true; the Aristotelian account of explanation is correct; the explanans (explainer) for these premises, if true, would entail the premises; and the truth of the explanans requires no explanation. (I don't say that the arguments succeed only if they satisfy the preceding conditions, because there are models of explanation other than Aristotle's; even if Aquinas' arguments do not succeed on the terms he sets, they might explain on terms set by another.) According to the Principle of Charity, we should interpret Aquinas' inferences as explanatory only if either this interpretation makes his arguments good ones or there is no alternative interpretation which makes his arguments better than the explanationist interpretation does. To decide which of these interpretations is best, we need to figure out what the premises of Aquinas' arguments are. Then we can determine whether the premises entail Aquinas' conclusion, whether his conclusion would explain the premises were it true, and so on. First Way – From Motion Aquinas' first argument for God's existence appeals to ordering among motions. "Motion," for Aquinas, has a wider connotation than locomotion, and refers generally to any kind of change-in-state (growth, creation, and so on). 1.1 Some things are in motion. 1.2 Whatever is in motion is put in motion by another. a. Motion is reduction of something from potentially moving to actually moving. b. A thing is reduced from potentially moving to actually moving only if something actually moving causes the thing to actually move. c. Nothing that is potentially moving is, at the same time, actually moving in the same respect. 1.3 Hence, there is a causal series of motions. Nicholaos Jones (2012) 1.4 No causal series of motion can go on to infinity. a. If there were an infinite number of members in a causal series of motion, there would be no first member of that series. b. If there were no first member in a causal series of motion, there would be no other members. c. But there are members in some causal series of motions (see #1.3). 1.5 Hence, there must be a first mover which causes motion without being caused to move. 1.6 Therefore, God exists. While he does not explicitly say so, Aquinas' example of the hand moving the staff might be a clue that he has in mind per se causal series of motion (because the hand-stick case is a paradigm case of per se causal order). The causes of motion in such a series occur simultaneously with their effect. If the explanationist interpretation is correct, the argument must contain an explanandum (probably 1.1), the argument for 1.4 establishes a constraint for explaining this explanandum, and the support for 1.5 is that, given this constraint, the existence of an unmoved mover is the best (or only) explanation of the explanandum. In addition, 1.4 probably should be re-interpreted to say that no infinite series of (per se) motions explains why some things are in motion. Second Way – From Efficient Causation Aquinas' second argument for God's existence appeals to "an order of efficient causes." (Is this a per se order or a per accidens order? Which interpretation is most charitable to Aquinas?) 2.1 Some things are caused. 2.2 Nothing is an efficient cause of itself. a. Causes are prior to their effects. b. Nothing is prior to itself. 2.3 Hence, there is an order of efficient causes. 2.4 No order of efficient causes can be infinite. a. If there were an infinite number of members in a causal series, there would be no first member of that series. b. If there were no first member in a causal series, there would be no other members. c. But there are members in some causal series (see #2.3). 2.5 Hence, there must be a first cause which causes without being caused. 2.6 Therefore, God exists. Which kind of causal order does Aquinas have in mind? If the deductivist interpretation is correct, the argument must have all true premises and be valid. Certainly, as reconstructed, it is valid. The weakest link, it seems, is 2.4—and, in particular, 2.4b. If the explanationist interpretation is correct, the argument must contain an explanandum (probably 2.1), the argument for 2.4 establishes a constraint for explaining this explanandum, and the support for 2.5 is that, given this constraint, the existence of an uncaused causer is the best (or only) explanation of the explanandum. In addition, 2.4 probably should be re-interpreted to say that if there no infinite regress of efficient causes explains why something is caused. Nicholaos Jones (2012) Third Way – From Possibility Aquinas' third argument appeals to "possibility"—that is, to the existence of things that are "possible to be and not to be." These things are beings that exist at some, but not all, times—beings, as Aquinas would say, that exist "in" time. (A thing that exists "outside" of time is either a thing that exists at all times or a thing that exists at no time. Since, of these, only the former (exists at all times) is a being, a being exists "outside" of time if and only if it exists at all times.) 3.1 Some beings exist at some, but not all, times. 3.2 If a being exists at some, but not all, times, its essence does not involve existence. a. Every being has its essence at all times. b. Hence, if a being's essence were to include existence, the being would exist at all times. c. Therefore, etc. 3.3 If a being's essence doesn't involve existence, it participates in something else that gives it existence. 3.4 Something can give existence only if it exists (has existence to give). 3.5 Either all beings are such that their essence does not involve existence, or some being is such that its essence involves existence. 3.6 But it is not the case that all beings are such that their essence does not involve existence. a. Suppose (for reductio) that all beings are such that their essence does not involve existence. b. Then any being which gives existence participates in something else which gives it existence. c. Hence, there is an infinite regress of beings participating in other beings for their existence. d. Such a regress is impossible. e. Therefore, etc. 3.7 Hence, some being is such that its essence involves existence. 3.8 Therefore, there is a being whose essence is identical to existence. a. If a ei g s esse e e e to i lude existence without being identical to existence, existence would be a category of that being. b. Existence is not a category of any being. c. Therefore, etc. The eg ess i . is a ki d of ausal se ies: … auses to exist [at time t]; w's existing [at time t] causes x to exist [at time t]; x's existing [at time t] causes y to exist [at time t]; y's existing [at time t] auses …. This satisfies the conditions for being a per se causal order. Hence, it is atemporal and transitive. If the explanationist interpretation is correct, the argument must contain an explanandum (probably 3.1), the argument for 2.6d establishes a constraint for explaining this explanandum, and the support for 3.7 is that, given this constraint, the existence of a being whose essence involves existence is the best (or only) explanation of the explanandum. In addition, 3.6 probably should be interpreted to say that no being whose essence doesn't involve existence explains the existence of other beings whose essence doesn't involve existence. Nicholaos Jones (2012)