Teleology, Priority, and The Ambitions of Ontology:

A Defense of Classical Platonism 1

Jason Bowers

North Carolina Agricultural and Technical State University

Contemporary discussions of ontology have produced two research programs: one concerned

with existence and one concerned with priority, or grounding. Both claim to be ambitious—i.e.

to investigate substantive questions not asked by science—and yet each fails to account for this

ambition. The existence program fails because certain existence claims are trivial; the brute

priority program fails because its notion of priority, when intelligible, is borrowed from science

in a way so as to lose ambition. In light of these considerations I propose a third option—

Classical Platonism—which identifies metaphysical priority with functional teleology.

1. Two Ontological Research Programs

The idea that the world contains metaphysically basic elements—elements in virtue of which all

other things exist and upon which all other things depend—is an intuitive one, but it does not

admit of an uncontroversial analysis. Yet today metaphysicians have at their disposal a multitude

of accounts of priority and dependence, and with them, a multitude of accounts of what it is to be

a metaphysically fundamental element of being. The philosophical name for such an element is 2

“primary substance.”

Ontology is the philosophical study of primary substance. It aims to discover what the

primary substances are, to elucidate the relations in terms of which their primacy is defined, and

to do so in light of various philosophical puzzles, such as the One over Many, the puzzle of

change, and Theseus’ Ship. Ontological theories are theories about the world’s most

© 2010, 2017. Please do not cite or use without the author’s permission.1

Canonical among this multitude are Fine (2001), Hoffman and Rosenkrantz (1994), Lowe (1998: 2

136-154), and Schaffer (2003, 2009). See also Bennett (2011), Cameron (2008), Jenkins (2013), Raven (2015), Schneider (2006), Sider (2012:142-164), Tahko (2015: 93-116), Trogdon (2013), and Wilson (2014).

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metaphysically basic constituents—what they are, what makes them basic, and how they relate to

everything else.

In characterizing ontology this way I invoke an Aristotelian doctrine, according to which

“the question of being is just the question of substance.” This doctrine is controversial. Other 3

philosophers find the notion of substance to be hopelessly obscure. They recognize a research

program called “ontology,” but it is not concerned with metaphysical priority or primary

substances; it is simply concerned with what exists. Rather than phrasing the question of being

as the question of substance, such philosophers phrase it as Quine did, with the three Anglo-

Saxon monosyllables “what is there?” We thus have two philosophical research programs, both

of which are called “ontology.” We’ll call the first research program the priority program, and

call its defenders priority theorists; and call the second research program the existence program,

and its defenders existence theorists. 4

Following Schaffer (2009), we’ll distinguish the two programs by their different

treatments of questions of existence: priority theorists adopt the permissive stance, focusing their

inquiry on the primary substances; while existence theorists adopt the restrictive stance, focusing

their inquiry on what exists.

To adopt the permissive stance is to hold that existence questions—i.e. instances of the

schema “does X exist?”—have obvious answers when their topic is metaphysical, that the

answer is usually “yes,” and that such questions are therefore not the end of metaphysical

investigation. In other words, priority theorists hold that existence is cheap; everything exists in 5

some sense. This includes numbers, fictional characters, round squares, the gods of every

religion, and the mereological sum of Proclus the Successor and his eponymous lunar crater.

Yet priority theorists also claim to have sparse ontologies. For by their lights, one’s

ontology includes not what one takes to exist, but what one takes to be the primary substances,

Aristotle, Metaphysics 1028b2-4.3

Quine (1948) presents the most canonical existence program, though not under that name. 4

Contemporary existence theorists include Azzouni (2004), Hofweber (2004), Sider (2007), and Van Inwagen (1998). For canonical defenses of the priority program, see Fine (2001) and Schaffer (2009).

The qualifier “when the topic is metaphysical” cannot be over-emphasized. To adopt the permissive 5

stance is to take up an attitude towards existence questions in metaphysics, as opposed to existence questions that arise in the sciences. See premise (c) of the Triviality Argument below.

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which are some but not all of the things that exist. So although priority theorists will admit that

numbers exist, they might also defend nominalism by arguing that numbers are not primary

substances—i.e. that they are metaphysically dependent on something else. Similarly, priority

theorists can admit that gods exist, but may also defend atheism by arguing that gods are

fictional characters. 6

To adopt the restrictive stance, by contrast, is to hold that existence questions seldom

have obvious answers when their topic is metaphysical, that their answers are not usually “yes,”

and that subsequently, they are interesting and suitable for metaphysical inquiry. In other words,

existence theorists hold that existence is not cheap, and they tend to be as frugal with its

attribution as priority theorists are with their notion of substantial primacy.

2. Their Mutual Presupposition: Ontology is Ambitious

What these two research programs agree on is that ontology is ambitious. In the anti-

metaphysical preamble to The Empirical Stance, Van Fraassen (2002:11) presents two ways that

ontology might proceed in its investigations, one of which is “ambitious,” the other of which is,

by contrast, “modest.” He distinguishes them by their relation to science:

…Actually, this project (i.e. ontology) takes two forms, one apparently modest and the

other ambitious. The modest is to bring to light the ontic commitments of our best

theories in science; the ambitious is to continue science so as to answer questions

scientists do not ask, but in the same way that science answers its questions. The modest

project may be no more than a deep-going study of the sciences, although perhaps

charged with a contentious presupposition about what such a study will bring to light.

Leave that aside for now. Let us consider the more relevant ambitious project of an

ontology to go beyond answers to questions already dealt with by the sciences

themselves. This is the project to engage in metaphysics as an extension of the sciences,

putatively pursued by the same means and realizing the same values.

See Schaffer (2009), §2.1 for an example of this strategy.6

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To claim that ontology is ambitious, then, is to claim two things: first, that it “answers questions

scientists do not ask,” and second, that it does so “in the same way that science answers its

questions.” The second condition requires, among other things, that the answers to ontological

questions are not trivial—i.e. their answers are not obvious in a way that renders further

investigation unnecessary. If it turned out that either (a) ontological questions all have trivial

answers, or (b) that ontological questions are already asked by scientists, then ontology would be

unambitious. So any ontological research program that entails either (a) or (b) is inconsistent

with ontology’s ambition.

Both existence theorists and brute priority theorists--the latter holding that metaphysical

priority is a primitive, unanalyzable notion--argue that ontology is ambitious. But because each 7

side entails either (a) or (b), neither is able to account for this ambition. The existence program

entails (a), that the central questions of ontology are trivial; the brute priority program entails (b),

that the central questions of ontology are, when intelligible, already answered by science.

3. How The Existence Program Loses Ambition

The Triviality Argument, as I shall call it, is the most well-known argument against the 8

existence program for ontology. It purports to show that the existence program is incompatible

with ontology’s ambition because it entails (a), that the central questions of ontology have trivial

answers:

c. If the task of ontology is to say what exists, then the ontological status of

numbers, properties, propositions, composites, and fictional characters is trivial.

d. But the ontological status of numbers, properties, propositions, composites, and

fictional characters is not trivial.

Fine (2001) argues that the notion of grounding used in metaphysics is irreducible to any scientific 7

notion, and hence that metaphysical questions are not answered by science. Sider (2007) claims that answers to the special composition question are all “empirically adequate,” suggesting—though not requiring—that it is a distinctly metaphysical question. Van Inwagen (1998) argues that metaphysics, not science, is charged with regimenting scientific language in a way that yields metaphysical results. For more on the question of how ontology could be ambitious, see Hofweber (2009).

The most recent versions of this argument are presented in Fine (2001), Hofweber (2005), and Schaffer 8

(2009). Only Schaffer and Fine use the argument against the existence program; Hofweber argues for a distinction between two kinds of quantification, only one of which expresses ontological commitment.

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e. So it is not true that the task of ontology is to say what exists.

Because premise (d) follows from the idea that ontology is ambitious, and because (e) follows

from (c) and (d), it is (c) that does all the philosophical work.

Premise (c) is justified by a series of short arguments from trivially true premises, each of

which shows that one of the kinds of entities in question exists. As an example, consider the

following argument for the existence of numbers: 9

f. There are just as many bachelors as there are unmarried men.

g. So the number of bachelors is the same as the number of unmarried men.

h. So there is a number that numbers both the bachelors and the unmarried men.

The argument looks sound. (f) is indisputably true, since it is true by definition. (f) and (g) are

truth-conditionally equivalent, and (h) follows from (g) in classical predicate logic. So it seems

the existence of numbers--which, according to existence theorists, is a central question of

ontology—can be proven from analytic premises! Since the existence of numbers is so easily

proved, it is a trivial matter, and there is no ambition in its philosophical investigation.

Argument (f)-(h) is not one of a kind; recent literature has witnessed many variants, each

of which concerns a different kind of entity. There are now trivial proofs for the existence of

numbers, properties, propositions, composites, and fictional characters—virtually all the entities

discussed by ontologists. Since the existence program claim that the task of ontology is to 10

investigate which things exist, arguments like (f)-(h) together show that the existence program

cannot account for ontology’s ambition.

Hofweber (2005).9

Fine (2001), Hofwever (2005), and Schaffer (2009). Hofweber’s arguments for numbers, properties, 10

and propositions proceed from analytically true claims like (f)—e.g. “either it is true or it is false that it is raining; therefore there is a proposition that is either true or false,” and “either Fido is a dog or not; therefore there is a property that Fido either does or does not have.” Schaffer’s arguments for numbers and properties are similar, but his arguments for composites and fictional characters proceed from obvious empirical truths instead of proceeding from analyticities—e.g. “my body has parts, such as hands; therefore something has parts,” and “Sherlock Holmes is a fictional character; therefore something is a fictional character.”

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Existence theorists are not helpless against the Triviality Argument. Azzouni (2006: 55,

82) denies that the quantificational idiom “there is” in (h) carries any ontological commitment—

i.e. that it implies anything about what exists. Distinguishing two sorts of quantification in

natural language, Hofweber (2005) argues that (h) only follows from (f)-(g) under a reading of

“there is” that carries no ontological commitment. Sider (2007) argues that (h) establishes the

existence of numbers only if the natural meaning of “there exists”--the one that “carves reality at

the joints”--is determined by our use of claims like (f)-(g). Van Inwagen (1998) employs the

notion of paraphrase to argue that (h) might not carry ontological commitment, depending on

available paraphrases. There are few knock-down arguments in philosophy, and, unsurprisingly,

the Triviality Argument is not one of them.

But an argument does not have to be knock-down for it to be sound, and I for one believe

it is sound. Azzouni (2006)’s “separation thesis,” according to which quantificational idioms

carry no existential commitment, precludes the most natural understanding of their truth

conditions. Hofweber (2005)’s similar denial about inference-preserving quantification in

natural language rests on the distinction between failing to refer and successfully referring to a

nonexistent object--one that blurs when attempting to say what reference to nonexistents would

have to be. Sider (2007)’s appeal to natural quantifier meanings employs a notion--11

naturalness--that is far richer than that of existence, resulting in something more like a priority

program than an pure existence program. Finally. one cannot avoid a theory’s commitments by

accepting something synonymous with it, but it is unclear what Van Inwagen (1998)’s notion of 12

paraphrase could be if not something like synonymy. I conclude that existence theories fail to

account for ontology’s ambition. Brute priority theories, however, are no better off.

4. How The Brute Priority Program Loses Ambition

There are two versions of the priority program: the brute version, which holds that metaphysical

priority is primitive and unanalyzable; and the defined priority program, which holds that

metaphysical priority can be defined in more basic terms.

See Hofweber (2000).11

Alston (1957) and Jackson (1980).12

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The Intelligibility Argument, as I shall call it, purports to show that the brute priority

program is incompatible with ontology’s ambition: 13

i. If the task of ontology is to say what is primary in a brute, purely metaphysical

sense, then ontological questions are unintelligible.

j. But ontological questions are intelligible.

k. So it is not true that the task of ontology is to say what is primary in a brute,

purely metaphysical sense.

Premise (j) just follows from the idea that ontology is ambitious, and (k) just follows from (i) and

(j); therefore it is (i) that does all the philosophical work.

Premise (i) is motivated by the idea that, while there are many intelligible notions of

priority, none of them are primitively and distinctly metaphysical. Rather, what contemporary 14

theorists call “metaphysical priority” is a family of vaguely similar relations, many of which

come from the sciences, and none of which can be identified with the metaphysical notion

without rendering ontology unambitious. This is revealed in the examples from Schaffer

(2009)’s defense of the brute priority program.

Schaffer (2009, 2010) defends a brute notion of metaphysical priority, claiming all of the

following as cases of it: (l) the relation between the quantum state of an entangled system and the

states of its components, (m) the relation between an entity and its singleton, (n) the relation

between Swiss cheese and its holes, (o) the relation between truths and the world, and (p) the

relation between the piety of an action and Euthyphro’s gods’ love of it. The problem is that,

although each of (l)-(p) is an example of a priority relation, none of them are examples of the

same relation, nor are any of them particularly metaphysical.

The argument is a variation on one presented in Hofweber (2009), though I ultimately draw a different 13

conclusion. We agree that a primitive, distinctly metaphysical notion of priority is unintelligible, but he defends a modified version of the existence program while I defend a modified version of the priority program.

R is a priority relation iff R is an anti-symmetric, irreflexive, transitive relation with a lower bound. Some 14

of the relations from (l)-(p) are like priority relations, in that they have most but not all of these formal properties. Mathematical derivability, for instance, lacks asymmetry. Unless the properties they lack are distinctly relevant to our discussion, however, these priority-like relations will also be referred to as “priority relations.”

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Consider the first case. It is true that the quantum state of an entangled system is prior to

its components, but only in a mathematical sense—i.e. only in the sense that the former is not

mathematically derivable from the latter. Schaffer writes that “the EPR state is… not derivable

from the state of its two particles,” and this is supposed to suggest something about their 15

metaphysical status. But is mathematical derivability the same thing as metaphysical priority?

Not if ontology is ambitious. The facts about mathematical derivability are already studied by

another field, namely mathematics, and ontology has little to contribute. Example (l) does not 16

illustrate anything primitively metaphysical, only something mathematical.

The same is true for (m). An entity is indeed prior to its singleton, but only in the sense

that the latter is defined in terms of the former. In set theory, sets are defined by their members,

not vice versa. The sense of priority according to which entities are prior to singletons is priority

of set-theoretic definition. But is priority of set-theoretic definition the same thing as

metaphysical priority? Presumably not—no more than the latter is the same as mathematical

derivability. Metaphysical priority cannot be identified with the set-theoretic priority of entity to

singleton, and so (m), like (l), fails to illustrate anything distinctly metaphysical.

Likewise for (n), the case of the Swiss cheese and its holes. The cheese is indeed prior to

its holes, but only in the sense that the holes are proper parts of it. The holes are in the cheese 17

in the same way that pages are in a book or stitches are in a sweater. The priority of cheese to

holes is a matter of mereology, which, like mathematics, has applications within ontology. But if

ontology is ambitious, it should not reduce to mereology any more than it should reduce to set

theory or mathematics. 18

Schaffer (2010).15

Additionally, Schaffer’s claim that metaphysical priority is irreflexive is incompatible with its being the 16

same thing as mathematical derivability.

The protagonist known as Argle defends this claim in a dialogue from Lewis and Lewis (1970). 17

Alternatively, one might treat the holes as limits of the cheese.

More than one commentator has proposed that mereology is a piece of metaphysics, and that 18

mereology is somehow itself metaphysical. This is false. The reason why it is false is that we can develop all kinds of mereologies--classical ones, paraconsistent ones, fuzzy ones--and mereology is just the study of their formal properties. There is a metaphysical question about which mereology, if any, is the correct one--the one that “carves reality at the joints,” as it were. But such a question is no more part of mereology than the question of nominalism is part of algebra.

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Metaphysical priority cannot be identified with the relation obtaining between truths and

the world—the “true of” relation. For one thing, most alleged cases of metaphysical priority—

including (l)-(o)—involve pairs of entities that cannot have truth values. Furthermore, because

ontology does not tell us exactly which claims are true, its concern with truth would have to be

the investigation of the truth predicate’s semantic and syntactic properties. But this latter task

already falls in the domains of linguistics and logic. Linguistic science is one thing, metaphysics

another, and the “true of” relation, which barely resembles a priority relation to begin with,

certainly does not look like a metaphysical one. 19

Finally, the relation between the love of Euthyphro’s gods and the piety of an action they

love is, if not causal, at the very least a counterfactual relation: had the action not been pious, the

gods would not have loved it. Yet metaphysical priority cannot be counterfactual dependence, 20

for that would imply that every effect is metaphysically dependent on its cause--i.e. that causes

are more fundamental than their effects, which seems false. When a baseball shatters a window

by striking it, the shattering is counterfactually dependent on the striking, but the shattering is not

less fundamental than the striking. So metaphysical priority is not counterfactual dependence.

Just as (l)-(p) fail to distinguish a uniquely metaphysical relation, so does (p).

Brute metaphysical priority is not a single, univocal relation obtaining across cases like

(l)-(p). Nor can it be any one of the relations illustrated in (l)-(p), lest ontology lose its ambition.

To the extent that brute metaphysical priority is rendered intelligible through examples like (l)-

(p), its ontological study is unambitious.

Defenders of the brute priority program have three available responses to the

Intelligibility Argument. First, they could argue that metaphysical priority is a univocal but

multiply realizable relation, which is differently realized in each of (l)-(p). Second, they could

argue that metaphysical priority is a univocal but determinable relation, whose determinants

include the different relations from (l)-(p). Finally, they could argue that metaphysical priority is

Schaffer (2009: 375) appeals to truthmaking as a clear example of metaphysical priority, yet this does 19

not explain the notion at work so much as presuppose it. It is fully compatible, for instance, with “metaphysical priority” naming nothing but a family of vaguely similar but ultimately non-metaphysical relations.

Hofweber (2009) originally states this criticism.20

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a brute, distinctly metaphysical relation in addition to the other relations from (l)-(p). None of

these strategies, however, will save the brute priority program from the Intelligibility Argument.

First, one might argue that metaphysical priority is multiply realizable, like the properties

of being food or being a wing. Just as a variety of physical objects can all count as food,

provided that they play the same role in nourishing an organism, and just as a variety of physical

objects can all count as wings, provided that they play the same role in facilitating flight, so,

under this proposal, would each relation from (l)-(p) count as metaphysical priority, provided

that they play the same functional role in each instance. But what could this common functional

role be? Beyond some formal properties like irreflexivity, transitivity, and the like, which do not

constitute a functional role in any obvious sense, the relations from (l)-(p) resemble one another

very little, and there does not seem to be a common role they play in each example. So appeals

to multiple realizability will not save the priority program from the Intelligibility Argument.

Second, one might argue that metaphysical priority is a determinable relation, of which

the relations in (l)-(p) are determinants. For this to be true, however, metaphysical priority must

obey the logic of determinants and determinables. Central to this logic is the claim that no single

thing can have more than one determinant of the same determinable at once. So if metaphysical

priority is a determinable relation, and if the relations from (l)-(p) are among its determinants,

then no two things can stand in more than one of the relations from (l)-(p) at once. Yet two

things can stand in more than one of the relations from (l)-(p) at once: a pattern of dots on a dot-

matrix, for instance, is not only mathematically derivable from the positions of the individual

dots; it is defined in terms of them, and has them as proper parts. If metaphysical priority is a

determinable relation, and if its determinants include the relations in (l)-(p), then no pair of

objects can stand in more than one of the relations from (l)-(p) at once. Yet pairs of objects can

stand in more than one of the relations from (l)-(p) at once. So appeals to determinable relations

will not save the brute priority program from the Intelligibility Argument.

Finally, defenders of a brute priority program might hold that metaphysical priority is a

brute relation in addition to those of mathematical derivability, parthood, and the like; and that

the entities mentioned in (l)-(p) stand in relations of metaphysical priority in addition to the

relations already mentioned. The problem with such an approach is that, if metaphysical priority

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cannot be defined, and if metaphysical priority is completely distinct from every other relation--

such as derivability, definability, and causation--then ontological questions, like whether wholes

are prior to their parts, cannot be settled just by settling whether wholes are definable in terms of

their parts, or whether their features are derivable from their parts’ features, or whether the facts

about them supervene on the facts about their parts. Even if a whole has emergent properties, it

is still a fair question to ask, “what does that have to do with metaphysical priority?” Why

should the metaphysical priority of a whole follow from the non-derivability of its features?

Similarly, it is unclear how the metaphysical priority of part to whole could follow from the

whole’s supervening on its parts, or from the whole’s being defined in terms of them, or from

any other relation that might hold between the two. If metaphysical priority is brute, and entirely

distinct from relations of derivability and the like, then there is no prima facie reason for

inferring facts about the former from facts about the latter. An “in-addition” theory of brute

metaphysical priority thus places ontology among the occult disciplines, leaving no clear method

for its study. It will not save the brute priority theorist from the Intelligibility Argument.

In the end, there is no need to posit a brute relation of metaphysical priority. For as long

as a tight circle of inter-definability links the notions of metaphysical priority and primary

substance--with the primary substances just being whatever is metaphysically prior to

everything, and metaphysical priority just being the relation borne by the primary substances to

everything else--ontology will have to operate by canvassing intuitions about brute metaphysical

priority. Yet it is doubtful that we have such intuitions, especially once we distinguish brute

metaphysical priority from other relations, such as mathematical derivability, set-theoretic

membership, and proper parthood. Taking metaphysical priority and substantial primacy as

primitives, then, will not suffice for the foundations of an ontological program. If ontology has

ambition, there must be another way to account for it. Fortunately, there is.

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5. Classical Platonism: Metaphysical Priority is Teleological

Before dying of hemlock poisoning in the Phaedo, Socrates claims that a correct theory of the

Forms will explain why things exist, and that it will do so in terms of what is best. This kind of 21

normative explanation later came to be known as final or teleological causation, and identifying

metaphysical priority with it was what separated Plato’s followers from the rest of antiquity. 22

They saw the world as a mathematically structured teleological hierarchy, with the Form of the

Good at the top, pure mathematical patterns immediately below it, followed by goal-directed

systems which realize those patterns, and the material parts and aspects of such systems at the

very bottom.

Let Classical Platonism be the conjunction of two claims: 23

q. The task of ontology is to say what the primary substances are.

and

r. Metaphysical priority is teleological dependence.

Classical Platonists identify metaphysical priority with the relation that things bear to their

proper functions. Let us begin our discussion by examining this very relation in detail.

5.1. Teleological Dependence

To understand teleological dependence, let’s consider just one ordinary example: a

broom, whose proper function is to sweep. By noticing certain facts about the broom’s

relationship to sweeping, we will see that teleological dependence is a certain kind of normative

dependence—one that supports claims about value, in addition to claims about identity.

Phaedo 99-101, especially 97c-d: “If one wished to know the cause of each thing, why it comes to be or 21

perishes or exists, one had to find what was the best way for it to be, or be acted upon, or act.” (Tr. Grube.)

Gerson (2005), ch.1.22

Today the word “Platonism” is usually used as a synonym for realism about transcendent universals, 23

particularly numbers. On my account, realism about transcendent universals is entailed by (r) and another Platonic idea, namely that the proper functions, which are prior to their possessors, exist as mathematical abstracta.

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To begin, let us note that having a proper function is different from performing it. A

broom can have the proper function of sweeping, even while it leans idly against a wall. As it

leans idly, we could point at the broom, and truthfully say that it is for sweeping, even though it

is not sweeping then. Furthermore, something can have a proper function without ever

performing it; consider a broom, which breaks right after being created, before it could ever be

used. During the brief moments of its existence, we could have pointed at the short-lived broom,

and truthfully said that it is for sweeping. Having a proper function does not, in general, require

one to perform it. 24

Likewise, it is possible to perform a proper function, which one does not have. For

example, in a pinch, you could sweep your floor with a live cat. You could even sweep quite

well, if the cat is fluffy and it cooperates. In such a case, the cat would perform the proper

function of sweeping. But even as Tibbles performed the proper function of sweeping, it would

not follow that sweeping is anything the cat is for. When rubbed across the floor as a makeshift

broom, Tibbles performs the proper function of sweeping without actually having it. 25

So there are two relations, which a thing can bear to its proper function: it can have that

proper function, or it can perform it. Which of these relations, exactly, is teleological priority?

Which one is the relation, which Platonists identify with metaphysical priority?

When we say that brooms are for sweeping, we mean that they have the proper function

of sweeping; thus, teleological dependence is this having relationship, which obtains between an

object and its proper function. If an object O has a proper function F then O is teleologically

dependent on F and conversely, F is teleologically prior to O. A broom is teleologically

dependent on sweeping, and sweeping is teleologically prior to the broom. The broom is for

sweeping, meaning that the broom depends on sweeping in a teleological way. Objects are

One potential counterexample to this, at first, might seem to be living organisms, if their proper function 24

is the activity of being alive. This is because the performance of such an activity consists in living, and an organism cannot exist unless it lives. However, for reasons discussed in §5.2 below, we should not think that an organism’s proper function is to be alive; we should think that its proper function is to flourish. Flourishing, moreover, is something an organism can fail to do, even while being alive; some living things do not flourish. So again, the possession of a proper function does not require its performance.

Sometimes, when we distinguish functions from proper functions, we do so on the basis of whether the 25

thing in question actually has the proper function that it performs. If it does, we say that the thing is performing its proper function, but if it doesn’t, we often say that performs a function, but not a proper one. This same distinction is present when we speak of merely serving a purpose rather than having one.

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teleologically dependent on whatever proper functions they have, and proper functions are

teleologically prior to the objects that have them. Let us turn to the details of this relation.

First, teleological priority is normative, in the sense that it provides a basis for claims

about value. Because a broom has the proper function of sweeping, this means a broom, which

can sweep efficiently, is a good broom. A broom, therefore, can be improved by acquiring traits,

which allow it to sweep more effectively. English parlance even permits us to say that treating

the broom, in a way that improves its performance, is good for the broom. Conversely, if a 26

broom cannot sweep efficiently, this makes it a bad broom. If a broom changes in ways that

make it less efficient at sweeping, this makes it worse. Ordinary English even permits us to say

that treating the broom, in a way that damages it, is bad for the broom. Thus, the broom’s

teleological dependence on sweeping provides grounds for evaluating it, and even for explaining

a sense in which we speak of something like its well-being. 27

Second, teleological priority is explanatory, in the sense that an object’s existence, along

with its behavior and its features, can be explained in terms of its proper function. Scholastic

Aristotelians famously called this sort of explanation “final causation,” and in English, we

request it with the question, “what’s the point?” In our example, the phrase “because it’s for

sweeping” is a perfectly good answer to several questions about the broom, including why it has

the shape that it does, why its owner wields it thusly, why its bristles are flexible, and even why

it exists at all. Not everything about the broom can be explained this way; depending on its

origins, there may be no purpose to its having a certain color, for instance, or a certain weight.

The explanations provided by proper functions are not the only explanations for such

phenomena; one could also explain the bristles’ flexibility by citing their constituent material, or

Thus Von Wright (1963: 50) writes, “It is not unnatural to say that lubrication is beneficial or good for the 26

car, or that violent shocks will do harm to a watch... Therefore that which is good for the car or watch is something that will keep it fit or in good order with a view to serving its purpose well.” As a contemporary example, consider the online help page for Mac OS X: it includes a section entitled, “Protecting your computer from harmful applications.” The two first sentences are particularly illustrative: “Some harmful applications exist that can cause problems for your computer. Frequently, a harmful application will try to appear as an innocent document, such as a movie or graphic file.”

Geach (1956)’s distinction between attributive and predicative adjectives is relevant here. There is a 27

huge difference between being a good broom and being a good thing which also happens to be a broom. For all its virtues, there may not be anything good about my broom from an ethical perspective. This is clearer if we replace the example with a weapon, such as a bomb. A good bomb is not necessarily something that is both a bomb and good.

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the forces that produced them, or their membership in some natural class. Yet teleology, which

states what the point of something is, supplies at least one kind explanation. That explanatory

relation is coextensive with teleological dependence. If an object has a proper function, then its

existence can be explained in terms of it.

Third, relations of teleological dependence provide constitutive standards; they establish

which kind of thing an object is. To see why, first note how impossible it is to ascribe multiple 28

proper functions to something without thereby classifying it as many different kinds of things.

If, in addition to sweeping, an object also has the proper function of swatting flies, this makes it a

fly-swatter or fly-whisk, in addition to a broom. If it acquires the proper function of decorating a

room for Halloween, this means the object becomes a Halloween decoration; and if it loses this

proper function, this means it ceases to be a Halloween decoration. The ascription of a proper

function requires membership in a natural kind. 29

Moreover, when we ask what distinguishes a real broom, on one hand, from something,

whose broom-like shape is due to mere coincidence, on the other, we find that the former, and

only the former, has the proper function of sweeping. What distinguishes brooms from broom

facsimiles, in other words, is what they are for. If a collection of wood and reeds happens to

congeal in a swamp, so that it becomes perfectly broom-shaped, and physically resembles a

broom in every way, down to the smallest structural detail, this would still not be a broom. The

reason why is that this “swamp-broom” would not be for sweeping. In fact, it would not be for

anything; there would be nothing on which it teleologically depends. What makes something a 30

Korsgaard (2009: 27-44).28

Here, “natural” means “not arbitrary or gerrymandered.” Thus, artifactual kinds, like the property of 29

being a table, or the property of being a butter knife, would count as natural. However, the property of being either a table or a butter knife, presumably, would not be natural.

The case in intentionally similar to the famous “swampman” case from Davidson (1987).30

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broom is not its broom-like shape or its suitability to be used as a broom. Rather, what makes

something a broom is its teleological dependence on sweeping. 31

For the same reason, teleological dependence explains why, if someone endowed a

perfectly usable, naturally-occurring “swamp broom” with the proper function of sweeping, that

would make it a broom. Intuitively, if someone found a perfectly usable, naturally-occurring

knot of swamp vegetation, which physically resembled a broom in every way, down to the

smallest structural detail, and if one took this “swamp broom” home and used it daily to sweep

one’s floor, it seems that, years later, one could truthfully point to it, saying, “that is my broom.”

Someone could do this, moreover, without changing the knot of vegetation in any other way. Yet

earlier, before using it or touching it, one could have pointed to that very same knot of

vegetation, and truthfully said, “that’s no broom.” What accounts for this? How can something

become a broom, if it undergoes no change in structure or composition? The answer is that, to be

a broom, it is not enough to be perfectly broom-shaped or perfectly usable as a broom. To be a

broom, one must be for sweeping; one must be teleologically dependent on it. Before being

adopted and habitually used, the knot of swamp vegetation was not for sweeping; after the right

pattern of use, however it acquired the proper function of sweeping. It became a broom by

coming to depend on sweeping, teleologically.

Teleological dependence has these three features, then: it provides a basis for evaluation,

for a certain kind of explanation, and for determining membership in natural kinds.

s. If an object O teleologically depends on proper functions F - Z, then by appealing

to F - Z, one can measure both O’s excellence and O’s well being, as well as

explain both O’s existence and O’s membership in natural kinds.

Likewise, consider a similar case. If, on the planet Zoth, intelligent creatures fashion a decorative 31

sculpture for the purpose of religious tribute, and if this sculpture just so happens to physically resemble a broom in every way, down to the smallest structural detail, this would still not be a broom. Again, the reason is that the Zothic sculpture is not for sweeping; it is for something else, namely paying religious tribute. A Zothic sculpture teleologically depends on the proper function of paying religious tribute; a broom teleologically depends on sweeping. A broom and a Zothic sculpture have different proper functions, and this is why a Zothic sculpture would not be a broom, and also why neither a broom from Earth nor a “swamp broom” from Zoth would be a Zothic sculpture.

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Here, (s) is not a definition of teleological dependence; it’s an identifying description in terms of

the relation’s most philosophically important properties. To complete our characterization, we

must consider two more: its many-to-many cardinality and its gradability. These properties are

connected, in that gradability solves a puzzle about teleological dependence, which arises when

considering its many-to-many cardinality.

A relation’s cardinality is many-to-many exactly when the relation can connect any

number of things to any other number of things. The authored by relation is many-to-many,

since many books can be authored by the same writer, just as the same book can be authored by

many writers. The in debt to relation is many-to-many, since many people can be in debt to the

same entity, just as the same person can be in debt to many entities. If a relation’s cardinality is

many-to-many, then, it means that it can relate any number of things to any other number of

things.

To say that teleological dependence is many-to-many, then, is to say that many objects

can be teleologically dependent on the same proper function, and also that the same object can be

teleologically dependent on many proper functions. The first claim is unproblematic: it is easy to

imagine several brooms that all have the same proper function of sweeping. The second claim,

however, may initially seem to pose a problem.

The problem is that improving an object’s capacity to perform one proper function might

interfere with its capacity to perform another, so that the very same changes to a single object

would simultaneously improve it while also making it worse. Since it is absurd for something to

be simultaneously improved and worsened by the very same changes, it would seem to follow

that, either no object can have more than one proper function, or else proper functions cannot be

used as standards of value.

As an example, consider a festively-constructed object O, which simultaneously has the

proper functions of a broom and of a Halloween decoration. O has the proper function of

sweeping, which makes it a broom, and O has the proper function of decorating the space in

which it is placed for Halloween, which makes it a Halloween decoration. Now suppose that, if

O’s bristles were bound with black and orange ribbons, this would make it a better Halloween

decoration, since it would improve the way in which O decorates its surroundings. However,

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binding O’s bristles with ribbons would also make it a worse broom, since the ribbons would

decrease the efficiency of its sweeping. So consider this single object. Would it improve O to be

tied with ribbons? Would the ribbons improve it? It seems we are faced with an absurdity: the

ribbons would simultaneously improve and also worsen the object, since it would make the

object a better decoration but a worse broom. Call this the Multiple Purpose Puzzle.

Fortunately, the Multiple Purpose Puzzle admits of several solutions. The first is to deny

that there is only one object in the imagined case. One could solve the problem, in other words,

by maintaining that there are two different objects—the decoration and the broom—which,

despite their distinctness, are co-located in the same space and constituted by the same materials.

If this were the case, then we would not have one single thing, which was simultaneously

improved and worsened by the ribbons; instead, we would have one thing—the decoration—

which is improved by the ribbons, and another thing—the broom—which is worsened by them. 32

A second way out of the puzzle is to deny that an object can be improved or harmed

simpliciter, and to say that a thing can only be improved or worsened relative to its various

proper functions. In our example, this second solution would imply that the object is made

worse, but only relative to the standard of sweeping, and also better, but only relative to the

standard of decorating. Furthermore, when one asks whether the object is made worse

simpliciter—whether it is just plain worse—this question would be treated as some kind of

category mistake. (Whether an object is just plain harmed, independently of its being harmed

relative to this or that function, would be like asking whether a sweater just plain fits,

independently of its fitting this or that individual.) Thus, the Multiple Purpose Puzzle can be

solved by relativizing the notions of harm and benefit to proper functioning: O would be

damaged in one way, and improved in another, rather than being impossibly damaged and

improved in the same way at the same time.

This solution is identical to the view about material objects, which Conee and Sider (2008) call 32

“Cohabitation,” and it is a long-standing proposal for solving the traditional puzzle of material constitution. One problem with Cohabitation is that it does not work well with living beings, particularly ourselves. If the same changes, for instance, would make me a worse professor but a better party animal, there would remain a lingering question of whether those changes would be good for me, that is, good for the single being, which is either the professor or the party-goer but not both. To say that the professor and party-goer are distinct beings, in other words, raises the absurd question of which one, exactly, I am, as well as the question of why I should care about what happens to the other one.

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Finally, a third solution to the Multiple Purpose Puzzle is to let teleological dependence

to admit of degrees. In other words, the solution is to let an object depend more on some proper

functions than on others. This would allow us to say that the proper function, on which an object

is most teleologically dependent, is the one that most determines its excellence or well-being. In

our example, the object O would be made just plain worse if it was more dependent on sweeping

than on decorating, and O would be made just plain better if it was more dependent on

decorating than on sweeping. In our example, the ribbons would make the object just plain

worse if the object is mainly for sweeping, and the ribbons would make the object just plain

better if the object is mainly for decorating. Thus, the Multiple Purpose Puzzle’s third solution is

to let teleological dependence be gradable, and to let things be damaged or improved based on

whatever they most depend on.

When combined with the second solution, this third solution provides an effective way to

model our understanding of how a thing’s purpose relates to its conditions of well-being. On a

combined view, multi-purposed objects like O can be damaged or improved in various ways,

each of which is relative to a proper function. Since teleological dependence is gradable,

moreover, this lets some of these ways be more important than others. Thus, in our example, O

not only could be damaged and improved in different ways; O also could be just plain damaged,

by being damaged relative the proper function it most depends on. Call this the Hybrid Solution

to the Multiple Purpose Puzzle.

We should accept the Hybrid Solution. The reason why is that, by making teleological

dependence gradable, it makes sense of how, in ordinary English, we rank different proper

functions as we ascribe them. This practice would be mysterious otherwise.

We commonly distinguish a thing’s primary function—its main function—from its

secondary or auxiliary functions. The seat cushions on commercial airlines were designed as

floatation devices, although that is not their main purpose. A mammal’s heart and kidneys are

supposed to secrete hormones, although that is not their primary function. A student might

attend class in order to see her friends, although she mainly attends in order to learn, or to get a

grade.

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Ordinarily, this way of speaking might seem mysterious. What is it for a proper function

or purpose to be primary, or main? It’s not that a primary function is the one an object acquires

first, or earliest, since an object can have multiple proper functions from the very beginning of its

existence, even while one of them is primary. Nor is an object’s primary function the one it

performs most often, since a bomb shelter, whose main purpose is to protect people from bombs,

might be used more often to store supplies. Nor is an object’s primary function the one it

performs most efficiently, since the main purpose of a student’s attendance, namely learning or

earning a grade, may be performed with far less efficiency than the secondary purpose of seeing

friends in class. Ordinarily, the phenomenon of ranking proper functions seems mysterious.

The Classical Platonist who adopts the Hybrid Solution, however, can easily solve this

mystery. To say that an object’s primary proper function is F is to say that, among the object’s

proper functions, F is the most important in answering questions about damage, improvement,

harm, and benefit. Since this importance is due to a gradable relation of teleological

dependence, it is natural to say that an object’s primary function is the one that it depends on

most. If teleological dependence admits of degrees, in other words, and if this dependence is

what determines an object’s conditions of well-being, then it follows that an object’s conditions

of well-being are most determined by the functions, on which it most teleologically depends:

t. If an object O teleologically depends on proper functions F - Z, and if O

teleologically depends most on F, then O’s ability to perform F is what most

affects O’s excellence and well-being.

Classical Platonism includes (t) as well as (s), meaning that teleological dependence is a gradable

relation of many-to-many cardinality, the facts about which provide a basis for evaluating

material objects, as well as explaining both their membership in natural kinds, as well as their

very existence.

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To complete the groundwork for a Classical Platonist ontology, we must discuss its

primary substances. What are these things—proper functions—whose very being explains why

we exist? What are these entities, which, according to Classical Platonism, are sources of value

and purpose? It is to these primary substances—Platonic Forms—that we will shortly turn,

before ultimately returning to the question of ontology’s ambitions.

Here, however, it is crucial to address a deep misunderstanding about Classical

Platonism, Platonic Forms, and teleological realism in general. It is an ethical misunderstanding

—one which has lead not only to pernicious theories but actual harm to human beings. Before

completing our survey with an examination of the Forms, we absolutely need to clarify why

realism about teleology does not support homophobia or transphobia, nor does it imply that

there is anything dysfunctional about LGBTQ relationships in any way.

5.2 Human Beings and Other Organisms

The proper function of an individual organism is to flourish, and that the proper function

of an organism of a specific kind is to flourish in a way that is distinct to that kind. As Foot

(2001) observes, we must distinguish this normative use of “proper function” from a purely

descriptive one, found in evolutionary biology, which refers to traits developed in the course of a

species’ adaptation to selection pressures: “To say that some feature of a living thing is an

adaptation is to place it in the history of a species. To say that it has a function is to say that it

has a certain place in the life of the individuals that belong to the species at a certain time.” An 33

ethics based on proper functioning, therefore, must distinguish an organism’s proper function

from traits, which are merely adaptive.

Many cases of adaptation are also cases of proper functioning, but the phenomena are

distinct. We human beings have adapted to possess aggressive and jealous tendencies, which, in

the lives of individuals, produce more misery than flourishing. Jealousy might be adaptive, for

instance, but it need not be part of our proper functioning. Likewise for biological reproduction,

which Benatar (2008) argues is merely adaptive. Or consider the case from Plantinga (1993:

194-199), in which evil geneticists have made it adaptive for a population to suffer from painful

Foot (2001: 32), footnote 10, emphasis added. 33

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blindness. Not all adaptations are proper functions, and being adaptive does not mean that

something is conducive to flourishing.

Likewise, not every way to flourish need be evolutionarily adaptive. Imagine a species,

whose flourishing consists in the exercise of abilities that developed as spandrels rather than as

adaptations. Imagine, for instance, an animal which flourishes through creative, artistic

expression, but whose capacity for it was neither artificially nor naturally selected. We human

beings may very well be examples of such an animal. Our flourishing, in other words, may well

consist in living a meaningful life, full of personal connections to profound phenomena—

something that evolution simply doesn’t select for.

To understand what human flourishing is, therefore—as opposed to hedgehog flourishing,

dung beetle flourishing, or mushroom flourishing—we cannot exclusively look to biology.

Instead, we must begin first with the question of what the best sort of human life is, as well as

which activities make it choice-worthy. Goods such as friendship and love, along with the

narrative features of a meaningful existence, and social projects such as the pursuit of justice and

peace, would presumably figure into the answer. Presumably, too, the best sort of human life

would be multiply realizable across different sorts of life-projects; one might live the best sort of

life as an artist, or as an engineer, or both, or neither. Whatever the general sorts of activities are,

which make a human life most choice-worthy, the Classical Platonist takes to be components of

human flourishing; and whatever the traits are, which allow human beings to perform those

activities, the Classical Platonist takes them to be the human virtues. Thus, the human purpose

and its associated ethics, according to Classical Platonism, is determined not merely by biology,

but also by psychological, sociological, narrative, and other evaluative factors.

This is why something as simple as biological reproduction cannot be the same thing as

human flourishing. To identify them would be to treat the human purpose as neither more nor

less interesting than that of plants or bacteria. It would fail to account for our creativity, our

complexity, and the diversity of ways we find meaning as we love and support one another. It

would mean that the most virtuous human being is simply one that breeds well—something

which should strike us as wholly absurd.

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Following (t), an organism’s flourishing plays a central role in determining its conditions

of well-being. So according to Classical Platonism, human beings exist in order to flourish and

do well in life. Yet this does not show what flourishing is, nor does it privilege conceptions of

human flourishing, which are heterosexist or otherwise chauvinistic. The meaning of life,

according to Classical Platonism, is to pursue the activities—whatever they may be!—which

lead to a healthy, meaningful, fulfilling existence. Exactly what those activities are, however, is

a further question—one not settled by biology alone, nor by culturally-bound prejudices.

5.3. Sweeping Itself, Flourishing Itself, and Other Platonic Forms

On one hand, a proper function is a type of process. More specifically, it is a

determinable type of process—meaning that it can be performed in different ways—and its

tokens, or instances, are individual performances of it. So the proper function of a broom,

sweeping, is a type of process that can be performed in a variety of ways: slowly, quickly, well,

poorly, and so on.

On the other hand, a Platonic Form is an abstract entity with “participants,” which is

somehow more fundamental than those participants, and whose being explains those participants’

existence, membership in natural kinds, and conditions of well-being. So the Platonic Form of 34

the Broom would be an abstract entity, which explained why brooms exist, what makes them

brooms, and why various conditions are either good or bad for brooms. Likewise, the Form of

the Hedgehog would be an ideal standard of hedgehog flourishing, whose existence explains the

purpose of being a hedgehog, as well as hedgehogs’ conditions of well-being.

Because Classical Platonism includes both (s) and (t), it is natural to identify proper

functions with Platonic Forms. If proper functions, in other words, are the primary substances of

reality, and if they are sources of being, value, and purpose in the way described so far, then a

Classical Platonist’s primary substances will be very much like the Forms described in Plato’s

dialogues.

Thus, for the Classical Platonist, proper functions are determinable transcendent

universals, whose instances are performances of them. Because they are determinable, a Form

34

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will have a multitude of determinants, each of which is a maximally specific way to perform it. A

determinant of the Form of the Broom, for instance, would be a maximally-specific way to

perform the proper function of sweeping. It would include everything from the broom’s shape

and appearance to the force with which it swept, the sorts of resistance it met, and the duration of

the sweeping. It would be one of many specific possible ways to sweep. Because there are

uncountably many ways to sweep, the Form of the Broom will have uncountably many

determinants. Likewise, a determinant of the Hedgehog Form would be a maximally-specific

way to flourish as a hedgehog. It would include the hedgehog’s physiology, its way of

developing, the details of every breath it ever took, they types of adventures it enjoyed, and so

on. A determinant of the Hedgehog Form, in other words, would be one of many specific

possible hedgehog lives. Because there are uncountably many ways to live as a hedgehog, the

Form of the Hedgehog will have uncountably many determinants. Thus, along with her

commitment to determinable Forms, the Classical Platonist also acquires an ontology of abstract

possibilia, in the form of those Forms’ uninstantiated determinants. These determinants can be

put to the same sort of work, to which Lewisian counterparts and possible worlds are assigned.

The determinants of a Platonic Form, moreover, have components of their own. In order

to live one of many possible hedgehog lives, for instance, one must have a great number of

properties, as well as parts with properties. Such properties include everything from spikiness

and mammal-hood to the property of being an eyeball, and even unit negative charge. By

appealing to the Forms’ determinants, Classical Platonism has access to possibilia; by appealing

to those determinants’ components, Classical Platonism has access to a theory of properties in

general.

A fully fleshed-out Classical Platonist ontology would include a complete Theory of the

Forms, with details about the modal systems it permits, discussions of alien properties, and

comparisons between “bundles” and “thick particulars.” The completion of such a theory lies

beyond this paper’s scope. However, the preceding sketch should provide an effective

groundwork for its completion.

Classical Platonism says that our world is ultimately a world of ideal purposes and

standards, which various things strive to perform. This striving need not be conscious; trees do

�24

not consciously grow towards the sun, nor do amoebae consciously split. Nor, unfortunately, is

there any guarantee that any striving is ever successful; perhaps no society will truly be just and

fair, just as, perhaps, no organism might ever be perfectly happy and healthy. Yet despite all

imperfection and unconsciousness, the ideals towards which all material beings strive are real,

indeed more real than the beings which strive. The ideal of hedgehog flourishing—that is, the

Form of the Hedgehog—is the reason why any hedgehog exists. It is the purpose of being one.

To perfectly instantiate the Hedgehog Form would be to live the perfect hedgehog life; to live a

worse hedgehog life would be to instantiate the Form of the Hedgehog less well; something that

instantiates the Hedgehog Form as poorly as possible would be a hedgehog, whose existence is

truly wretched; and a hedgehog, who ceases to instantiate the Hedgehog Form at all, also ceases

to live. The many different hedgehogs are all dependent on this one single Form, like many

different shadows cast by a single illuminated body. No hedgehog can exist apart from their

Form; shadow cannot exist without substance. On the Classical Platonist view, every material

object is as dependent on the Forms in this way. We, too, are shadows cast by greater purposes.

Our immersion in the world of material beings, therefore, is immersion in a world of

secondary substances. The physical objects—the tables, chairs, and parts thereof, with which we

are most immediately familiar—are also the least fundamental parts of reality. Our life among

such things is like a life among shadows, like the life of Plato’s cave-bound prisoners. And like

the escaped prisoner’s upward exploration, along the path that connects sunlight to shadow, our

own exploration of teleological dependence was meant to be a journey of increasing

illumination. Let us complete our journey by returning to the start, where we may face the shady

specters of triviality and unintelligibility.

6. The Intelligibility and Non-Triviality of Classical Platonism

The phenomenon of teleological dependence, though initially mysterious, has turned out to be a

very specific relation, whose features—both logical and metaphysical—can be stated in familiar

philosophical terms. Again, it turned out to be a gradable relation of many-to-many cardinality,

which connect material objects to processes that explain their existence, their natural kind

membership, and their conditions of well-being.

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We may conclude, therefore, that Classical Platonism avoids the specter of

unintelligibility. Unlike brute priority theories, Classical Platonism can specify the relation of

ontological dependence in informative terms. It does not require a commitment to an unanalyzed

relationship of grounding or priority.

More threatening to the Classical Platonist project, it seems, is the specter of triviality—

not because facts about proper functions follow from any statement whatsoever, as facts about

numbers appear to—but rather because facts about proper functions are discovered through

empirical observation and science, rather than through metaphysical theorizing. That a broom’s

proper function is to sweep, for instance, is not a conclusion of metaphysics; it’s the product of

ordinary practice. Likewise, the fact that the peacock’s feathers are for mating is not a

metaphysical discovery, gleaned from the mind of Dr. Pangloss; it is a discovery of biology. In

general, it seems that proper functions are discovered and studied outside the philosophy

classroom. So Classical Platonism, which identifies the study of proper functions with

fundamental ontology, threatens to hand the entire discipline of ontology over to the natural

sciences!

We must therefore face two pressing questions: first, are there any proper functions, or

facts about proper functions, which are properly studied in the philosophy classroom? Second,

is there any room for the traditional problems and methods of metaphysics, if Classical

Platonism is true?

Yes there are, and yes there is.

First, Classical Platonism provides semantic values for teleological discourse, in the

same way that a theory of possible worlds provides semantic values for modal discourse. To

illustrate, consider what a theory of possible worlds does for our modal talk. By positing and

appealing to possible worlds, we can clarify a host of modal phenomena: possibilities,

necessities, essences, dispositions, counterfactual dependence, and more. A theory of possible

worlds does not tell us which things are possible, or which things have essences; to know that,

we need to leave the philosophy armchair. A theory of possible worlds only explains how modal

claims can be true, and how they systemically relate. Likewise, by positing a theory of the

Forms, Classical Platonism can clarify a host of teleological phenomena: proper functions,

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virtues, vices, goals, processes, harms, and flourishing. A theory of the Forms would not tell us

which things have purposes, or what their purposes are; knowing that, like knowing which things

are possible, requires non-philosophical research. Nonetheless, a theory of the Forms explains

how teleological claims can be true, and how they systematically relate. Classical Platonism

provides a foundation for realism about teleology, in the way that possible worlds provide a

foundation for realism about modality.

Second, as discussed in section 5.2, the question of what constitutes human flourishing

cannot be answered through mere deference to biology, or even to the combined sciences of

biology, psychology, and sociology. For there is, in addition to these factors, purely

philosophical questions—central ones!—about what makes a life meaningful, fulfilling, and,

above all, good. How do love and friendship relate to the good life? How does a commitment to

justice? The question of human flourishing, though informed by the sciences, is still proper to

philosophy. Likewise for the question of identifying the virtues of human beings and their

societies. According to Classical Platonism, these are all questions of fundamental ontology.

Finally, there is the question of Goodness Itself, or the Form of the Good, which, if

included among Classical Platonism’s posits, will turn out to be a second-order Form, or the

purpose of purposes. Proper functions, according to Classical Platonism, are the link between

world and value. They connect how things are with how they are supposed to be. They bridge

the descriptive and the normative. Proper functions, in other words, are means to achieve

goodness. They teleologically depend on it. In light of (r), however, this would make goodness

itself—-the Form of the Good—into Classical Platonism’s sole primary substance. By positing a

Form of the Good, in other words, Classical Platonism would culminate in Platonic Monism, a

view which claims that everything is derived from the Good or the One, which is a simple,

abstract, principle of perfection. So there is an ontological question about whether Classical

Platonism entails a commitment to what, in history, has been known as Neoplatonism. The

question of this entailment, and the metaphysics of value associated with its investigation, is not

a scientific question. It, too, is an ontological one, investigated in the philosophy room, and it is

far from trivial.

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In addition to including the metaphysics of teleology and value, however, the Classical

Platonist project also vindicates, and makes new contributions to, traditional metaphysical

puzzles. Two of the most important ones are that of non-mereological aggregation in the

metaphysics of properties, and the Special Composition Question about material objects.

For some time, metaphysicians have sought a relation, which makes one thing out of

many, but which is neither the set-theoretic relation of membership nor the mereological relation

we call “ordinary parthood.” This sought-after relation is supposed to unite properties, in ways 35

that neither of the aforementioned relations can. In particular, this sought-after relation is 36

supposed to let components be integrated into a composite more than once at the very same time.

In an effort to construe this sought-after relation as a species of parthood, some philosophers

defend “compositional pluralism,” claiming that a single whole can have the same part “twice

over.” Yet the sought-after relation is so different from our ordinary ideas of parthood, and its

uses in metaphysics are so technical, that compositional pluralism has been mired in the hopeless

task of defending it’s name’s legitimacy. So far, like a creature of myth, this sought-after relation

has eluded capture by those who believe in it.

Yet the Classical Platonist claims to have found it: it is teleology. A teleological relation 37

can make one thing out of many, but not in a mereological way or in a set-theoretic way.

Teleology can make one process out of many steps, by connecting them to an end or goal. The

formal properties of teleological unity, moreover, differ from those of mereology. Most

importantly, the very same end can require a certain step to be taken multiple times, even

multiple times at once. For a party to achieve the end of singing “Happy Birthday,” for instance,

they might need to sing the note C# multiple times, and even multiple times at once. The step of

singing C# is related to the process of singing Happy Birthday, but as a step, not a part. A whole

cannot have a single part many times over at once, but a process can require taking a certain step

multiple times over at once.

See Armstrong (1986), Bennett (2013), Bowers (2017), Hawley (2010), Lewis (1986), and McDaniel 35

(2009).

Structural universals are properties, aggregated this way; states of affairs, or “thick particulars,” are 36

properties aggregated this way with thin particulars.

Bowers (2017)37

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Classical Platonism, therefore, offers a new way to make one thing out of many: a new

aggregative relation, which is neither mereological nor set-theoretic, and which allows

components to be had “many times over.” It is exactly what so many philosophers have been

seeking in the metaphysics of properties. It is philosophical gold. Yet it requires a metaphysic,

which treats structures and states of affairs as teleologically-infused composites. It requires us to

give Classical Platonism some consideration.

Secondly, Classical Platonism offers a promising new answer to Van Inwagen (1990)’s

Special Composition Question: under which conditions, exactly, do a collection of materials

compose something? Must they be glued together, or what? Following Plato and Aristotle,

Classical Platonism uses teleology to distinguish composite objects from mere heaps of parts.

It says that a collection of materials composes something exactly when there is a proper function,

for the sake of whose performance the materials have been arranged. Composite objects, in other

words, have proper functions. Mere heaps do not. According to Classical Platonism, composite

objects are goal-directed systems, whose parts are arranged for the sake of performing some

function; mere heaps, by contrast, are not goal-directed systems, and their materials are not

united for any purpose. That is the Classical Platonist’s answer. It not only vindicates the

ontological status of the Special Composition Question, and the legitimacy of its investigation; it

also makes a further, novel contribution towards its answer.

Classical Platonism avoids the specter of triviality, therefore, while also providing a

demonstrably intelligible account of an ambitious ontological project. It includes not only an

account of ontology, which is consistent with current philosophical practice; it also makes

significant contributions to that practice.

7. Conclusion: Ontology’s Ambitions and the End(s) of the World

Classical Platonism says that ontology studies purposes, treating them as fundamental units of

reality. In so doing, it gives light to what it means, exactly, to be fundamental, and it provides a

detailed groundwork for discussing proper functions, material objects, value, properties, and the

very meaning of life. It vindicates the practice of ontology, by tying it to notions of purpose and

value. It is clear and intelligible; it is far from trivial. We may indeed follow Aristotle’s

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suggestion to keep truth as a closer friend than Plato, but if the preceding investigation is correct,

we should happily enjoy the company of both. 38

Works Cited

Alston,William P. 1957. “Ontological Commitments.” Philosophical Studies: 8–17.

Aristotle. The Basic Works of Aristotle. McKeon (tr.). 2001. Modern Library Press.

Armstrong, David M. 1986. “A Defense of Structural Universals.” Australasian Journal of

Philosophy 64 (1): 85-89.

Azzouni, Jodi. 2004. Deflating Existential Consequence. Oxford University Press.

Bennett, Karen. 2017. “Having a Part Twice Over.” Australasian Journal of Philosophy 91 (1):

83-103.

-2011. “By Our Bootstraps.” Philosophical Perspectives 25 (1):27-41.

Bowers, Jason. Forthcoming. “Neither Mereology Nor Magic, but Teleology.” Southern Journal

of Philosophy.

Cameron, Ross P. “Turtles All the Way Down: Regress, Priority, and Fundamentality.”

Philosophical Quarterly 58: 230.

Fine, Kit. 2001. “The Question of Realism.” Philosophers’ Imprint 1/1.

Foot, Philippa. 2001. Natural Goodness. Oxford University Press.

Previous drafts of this paper were greatly improved with comments from Robert M. Adams, Simon 38

Blackburn, Thomas Hofweber, Katherin Koslicki, Bill Lycan, Ram Neta, Laurie Paul, C.D.C. Reeve, John Roberts, Geoff Sayre-McCord, Jonathan Schaffer, Meg Wallace, and Susan Wolf. I am indebted to their assistance, as well as to the editors and referees at Synthese.

�30

Gerson, Lloyd P. 2005. Aristotle and Other Platonists. Cornell University Press.

Hawley, Katherine. 2010. ‘Mereology, Modality, and Magic’. Australasian Journal of Philosophy 88 (1): 117-133.

Hoffman, Joshua. and Rosenkrantz, Gary. 1994. Substance Among Other Categories. Cambridge

University Press.

Hofweber, Thomas. 2009. “Ambitious, yet Modest, Metaphysics.” Printed in Metametaphysics,

ed. Chalmers, Manley, and Wasserman. Metametaphysics. Oxford University Press.

-2005. “A Puzzle About Ontology.” Nous 39: 256-283.

-2000. “Quantification and Non-Existent Objects.” in Empty Names, Fiction and the

Puzzles of Non-Existence, pp. 249-73. Anthony Everett and Thomas Hofweber (eds.) CSLI

Publications.

Jackson, Frank. 1980. “Ontological Commitment and Paraphrase.” Philosophy 55 (213):

303-315.

Jenkins, Carrie. 2013. “Explanation and Fundamentality.” In M. Hoeltje, B. Schnieder and A.

Steinberg (ed.s), Varieties of Dependence (Basic Philosophical Concepts Series), 2013, Munich:

Philosophia Verlag, pp. 211-42.

Korsgaard, Christine M. 2009. Self-Constitution. Cambridge University Press.

Lewis, David. 1986. “Against Structural Universals.” Australasian Journal of Philosophy 64 (1):

25-46.

�31

-1970. “Holes.” Co-authored with Lewis, Stephanie R. Australasian Journal of Philosophy

48: 206-12.

Lowe, Jonathan. 1998. The Possibility of Metaphysics. Oxford University Press.

McDaniel, Kris. 2009. ‘Structure-Making’. Australasian Journal of Philosophy 87 (2): 251-274.

Plato. Phaedo. Printed in Grube (tr.). 2002. Hackett Publishing Co.

Raven, Mike. 2015. “Ground.” Philosophy Compass 10 (5):322-333 (2015)

Reeve, C.D.C. 2007. “Plato on the Beautiful, the Philosophical, and the Genital.” Delivered at

the Illinois Classical Conference, Loyla University Chicago, October 5-6.

Schaffer, Jonathan. 2010. “Monism: The Priority of the Whole.” Philosophical Review 119:1, pp.

31-76.

-2009. “On What Grounds What” in Metametaphysics, ed. Chalmers, Manley, and

Wasserman. Metametaphysics. Oxford University Press.

Schnieder, Benjamin. 2006. “A Certain Kind of Trinity: Dependence, Substance, Explanation,”

Philosophical Studies 129: 393–419

Sider, Theodore. 2012. Writing the Book of the World. Oxford University Press.

-2007. “Ontological Realism.” Delivered at the University of North Carolina at Chapel Hill

Philosophy Colloquium.

-2001. Four-Dimensionalism. Oxford University Press.

�32

Tahko, Tuomas. 2015. An Introduction to Metametaphysics. Cambridge University Press.

Trogdon, Kelly. 2013. “An Introduction to Grounding.” In M. Hoeltje, B. Schnieder and A.

Steinberg (ed.s), Varieties of Dependence (Basic Philosophical Concepts Series), Munich:

Philosophia Verlag.

Quine, Willard Van Orman. 1948. “On What There Is.” Review of Metaphysics 2: 21-38.

Van Fraassen, Bas. 2002. The Empirical Stance. Yale University Press.

Van Inwagen, Peter. 1998. “Meta-Ontology.” Erkenntnis 48: 233-250.

Wilson, Jessica M. 2014. “No Work for a Theory of Grounding.” Inquiry 57 (5-6):535–579.

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