Let us simply assume that the respectable thesis is false and that things fall into various natural classes—hereinafter, simply classes. Some of the classes into which we sort things are more comprehensive than others: all dogs are animals, but not all animals are dogs; all animals are living organisms, but not all living organisms are animals …. But is this so? If there are, can we identify them? The former term, if not the latter, presupposes a particular position on one question about the nature of being: that everything is, that the universal class is the class of beings, the class of things that are.
Universals, if they indeed exist, are, in the first instance, properties or qualities or attributes i. It may be that the novel War and Peace is a universal, a thing that is in some mode present in each of the many tangible copies of the novel.
All three terms are objectionable. Aristotle believed in the reality of universals, but it would be at best an oxymoron to call him a platonist or a Platonic realist. This term, too is objectionable. At one time, those who denied the existence of universals were fond of saying things like:. It would not be a mere puff of sound but would rather be what was common to the many puffs of sound that were its tokens.
The old debate between the nominalists and the realists continues to the present day. Most realists suppose that universals constitute one of the categories of being. This supposition could certainly be disputed without absurdity. Perhaps there is a natural class of things to which all universals belong but which contains other things as well and is not the class of all things. But few if any philosophers would suppose that universals were members of forty-nine sub-categories—much less of a vast number or an infinity of sub-categories.
If dogs form a natural class, this class is—by the terms of our definition—an ontological sub-category. A case can be made for saying that it does, based on the fact that Plato's theory of forms universals, attributes is a recurrent theme in Aristotle's Metaphysics. We shall be concerned only with ii.
In the terminology of the Schools, that criticism can be put this way: Plato wrongly believed that universals existed ante res prior to objects ; the correct view is that universals exist in rebus in objects. It is because this aspect of the problem of universals—whether universals exist ante res or in rebus —is discussed at length in Metaphysics , that a strong case can be made for saying that the problem of universals falls under the old conception of metaphysics.
And the question whether universals, given that they exist at all, exist ante res or in rebus is as controversial in the twenty-first century as it was in the thirteenth century and the fourth century B.
If we do decide that the problem of universals belongs to metaphysics on the old conception, then, since we have liberalized the old conception by applying to it the contemporary rule that the denial of a metaphysical position is to be regarded as a metaphysical position, we shall have to say that the question whether universals exist at all is a metaphysical question under the old conception—and that nominalism is therefore a metaphysical thesis.
There is, however, also a case to made against classifying the problem of universals as a problem of metaphysics in the liberalized old sense.
For there is more to the problem of universals than the question whether universals exist and the question whether, if they do exist, their existence is ante res or in rebus. For example, the problem of universals also includes questions about the relation between universals if such there be and the things that are not universals, the things usually called particulars.
Aristotle did not consider these questions in the Metaphysics. One might therefore plausibly contend that only one part of the problem of universals the part that pertains to the existence and nature of universals belongs to metaphysics in the old sense. At one time, a philosopher might have said,. Therefore, questions about its nature belong to metaphysics, the science of things that do not change.
But dogs are things that change. Therefore, questions concerning the relation of dogs to doghood do not belong to metaphysics. But no contemporary philosopher would divide the topics that way—not even if he or she believed that doghood existed and was a thing that did not change. Let us consider some aspects of the problem of universals that concern changing things.
That is, that concern particulars—for even if there are particulars that do not change, most of the particulars that figure in discussions of the problem of universals as examples are things that change. Consider two white particulars—the Taj Mahal, say, and the Washington Monument. And suppose that both these particulars are white in virtue of i. All white things and only white things fall under whiteness, and falling under whiteness is what it is to be white. We pass over many questions that would have to be addressed if we were discussing the problem of universals for its own sake.
For example, both blueness and redness are spectral color-properties, and whiteness is not. What is it about the two objects whiteness and the Taj Mahal that is responsible for the fact that the latter falls under the former?
Or might it be that a particular like the Taj, although it indeed has universals as constituents, is something more than its universal constituents? Or might the Taj have constituents that are neither universals nor substrates?
Is the Taj perhaps a bundle not of universals but of accidents? Or is it composed of a substrate and a bundle of accidents? And we cannot neglect the possibility that Aristotle was right and that universals exist only in rebus. The series of questions that was set out in the preceding paragraph was introduced by observing that the problem of universals includes both questions about the existence and nature of universals and questions about how universals are related to the particulars that fall under them.
We can contrast ontological structure with mereological structure. A philosophical question concerns the mereological structure of an object if it is a question about the relation between that object and those of its constituents that belong to the same ontological category as the object.
For example, the philosopher who asks whether the Taj Mahal has a certain block of marble among its constituents essentially or only accidentally is asking a question about the mereological structure of the Taj, since the block and the building belong to the same ontological category. Many philosophers have supposed that particulars fall under universals by somehow incorporating them into their ontological structure. And other philosophers have supposed that the ontological structure of a particular incorporates individual properties or accidents—and that an accident is an accident of a certain particular just in virtue of being a constituent of that particular.
Advocates of other theories of universals are almost always less liberal in the range of universals whose existence they will allow. And it seems that it is possible to speak of ontological structure only if one supposes that there are objects of different ontological categories.
For a recent investigation of the problems that have been discussed in this section, see Lowe They make up the most important of his ontological categories. This last feature could be put this way in contemporary terms: if the prote ousia x exists at a certain time and the prote ousia y exists at some other time, it makes sense to ask whether x and y are the same, are numerically identical and the question must have a determinate answer ; and the question whether a given prote ousia would exist in some set of counterfactual circumstances must likewise have an answer at least if the circumstances are sufficiently determinate—if, for example, they constitute a possible world.
More on this in the next section. It is difficult to suppose that smiles or holes have this sort of determinate identity. The question whether there in fact are substances continues to be one of the central questions of metaphysics. Several closely related questions are: How, precisely, should the concept of substance be understood? Depending on how one understood the word or the concept one might say either that Hume denied that there were any substances or that he held that the only substances or the only substances of which we have any knowledge were impressions and ideas.
We now turn to topics that belong to metaphysics only in the post-Medieval sense. Philosophers have long recognized that there is an important distinction within the class of true propositions: the distinction between those propositions that might have been false and those that could not have been false those that must be true. Compare, for example, the proposition that Paris is the capital of France and the proposition that there is a prime between every number greater than 1 and its double.
Both are true, but the former could have been false and the latter could not have been false. Likewise, there is a distinction to be made within the class of false propositions: between those that could have been true and those that could not have been true those that had to be false. The types of modality of interest to metaphysicians fall into two camps: modality de re and modality de dicto.
If modality were coextensive with modality de dicto , it would be at least a defensible position that the topic of modality belongs to logic rather than to metaphysics. Indeed, the study of modal logics goes back to Aristotle's Prior Analytics.
But many philosophers also think there is a second kind of modality, modality de re —the modality of things. The modality of substances, certainly, and perhaps of things in other ontological categories.
There are two types of modality de re. The first concerns the existence of things—of human beings, for example. And if what she has said is indeed true, then she exists contingently. That is to say, she is a contingent being: a being who might not have existed. A necessary being, in contrast, is a being of which it is false that it might not have existed. Whether any objects are necessary beings is an important question of modal metaphysics.
Some philosophers have gone so far to maintain that all objects are necessary beings, since necessary existence is a truth of logic in what seems to them to be the best quantified modal logic. See Barcan for the first modern connection between necessary existence and quantified modal logic.
Barcan did not draw any metaphysical conclusions from her logical results, but later authors, especially Williamson have. The second kind of modality de re concerns the properties of things.
Like the existence of things, the possession of properties by things is subject to modal qualification. Additionally there may be properties which some objects have essentially. A thing has a property essentially if it could not exist without having that property. Examples of essential properties tend to be controversial, largely because the most plausible examples of a certain object's possessing a property essentially are only as plausible as the thesis that that object possesses those properties at all.
For example, if Sally is a physical object, as physicalists suppose, then it is very plausible for them to suppose further that she is essentially a physical object—but it is controversial whether they are right to suppose that she is a physical object. And, of course, the same thing can be said, mutatis mutandis , concerning dualists and the property of being a non-physical object.
It would seem, however, that Sally is either essentially a physical object or essentially a non-physical object. The most able and influential enemy of modality both de dicto and de re was W.
Quine, who vigorously defended both the following theses. First, that modality de dicto can be understood only in terms of the concept of analyticity a problematical concept in his view. Secondly, that modality de re cannot be understood in terms of analyticity and therefore cannot be understood at all. Quine argued for this latter claim by proposing what he took to be decisive counterexamples to theories that take essentiality to be meaningful. What then, Quine proceeded to ask, of someone who is both a mathematician and a cyclist?
Since this is incoherent, Quine thought that modality de re is incoherent. Kripke and Plantinga's defenses of modality are paradigmatically metaphysical except insofar as they directly address Quine's linguistic argument. Both make extensive use of the concept of a possible world in defending the intelligibility of modality both de re and de dicto. For Kripke and Plantinga, no being, not even God, could stand outside the whole system of possible worlds.
A Kripke-Plantinga KP world is an abstract object of some sort. Let us suppose that a KP world is a possible state of affairs this is Plantinga's idea; Kripke says nothing so definite. Consider any given state of affairs; let us say, Paris being the capital of France.
This state of affairs obtains, since Paris is the capital of France. By contrast, the state of affairs Tours being the capital of France does not obtain.
The latter state of affairs does, however, exist, for there is such a state of affairs. Obtaining thus stands to states of affairs as truth stands to propositions: although the proposition that Tours is the capital of France is not true, there nevertheless is such a proposition. The state of affairs x is said to include the state of affairs y if it is impossible for x to obtain and y not to obtain.
If it is impossible for both x and y to obtain, then each precludes the other. A possible world is simply a possible state of affairs that, for every state of affairs x , either includes or precludes x ; the actual world is the one such state of affairs that obtains. Using the KP theory we can answer Quine's challenge as follows. In every possible world, every cyclist in that world is bipedal in that world.
Assuming with Quine that necessarily cyclists are bipedal. Apparently he had not foreseen adaptive bicycles. Nevertheless for any particular cyclist, there is some possible world where he the same person is not bipedal.
Once we draw this distinction, we can see that Quine's argument is invalid. More generally, on the KP theory, theses about de re essential properties need not be analytic; they are meaningful because they express claims about an object's properties in various possible worlds.
We can also use the notion of possible worlds to define many other modal concepts. For example, a necessarily true proposition is a proposition that would be true no matter what possible world was actual. Kripke and Plantinga have greatly increased the clarity of modal discourse and particularly of modal discourse de re , but at the expense of introducing a modal ontology, an ontology of possible worlds.
Theirs is not the only modal ontology on offer. What we call the actual world is one of these concrete objects, the spatiotemporally connected universe we inhabit. There is, Lewis contends, a vast array of non-actual worlds, an array that contains at least those worlds that are generated by an ingenious principle of recombination, a principle that can be stated without the use of modal language In the matter of modality de dicto , Lewis's theory proceeds in a manner that is at least parallel to the KP theory: there could be flying pigs if there are flying pigs in some possible world if some world has flying pigs as parts.
But the case is otherwise with modality de re. Since every ordinary object is in only one of the concrete worlds, Lewis must either say that each such object has all its properties essentially or else adopt a treatment of modality de re that is not parallel to the KP treatment. He chooses the latter alternative. If all Socrates' counterparts are human, then we may say that he is essentially human. If one of Hubert Humphrey's counterparts won the counterpart of the presidential election, it is correct to say of Humphrey that he could have won that election.
In addition to the obvious stark ontological contrast between the two theories, they differ in two important ways in their implications for the philosophy of modality. For Kripke and Plantinga, however, modal concepts are sui generis , indefinable or having only definitions that appeal to other modal concepts.
Secondly, Lewis's theory implies a kind of anti-realism concerning modality de re. Socrates, therefore, may well have non-human counterparts under one counterpart relation and no non-human counterparts under another.
And the choice of a counterpart relation is a pragmatic or interest-relative choice. But on the KP theory, it is an entirely objective question whether Socrates fails to be human in some world in which he exists: the answer must be Yes or No and is independent of human choices and interests. Whatever one may think of these theories when one considers them in their own right as theories of modality, as theories with various perhaps objectionable ontological commitments , one must concede that they are paradigmatically metaphysical theories.
They bear witness to the resurgence of metaphysics in analytical philosophy in the last third of the twentieth century. Long before the theory of relativity represented space and time as aspects of or abstractions from a single entity, spacetime, philosophers saw space and time as intimately related. Kant, for example, treated space and time in his Transcendental Aesthetic as things that should be explained by a single, unified theory. And his theory of space and time, revolutionary though it may have been in other respects, was in this respect typical of philosophical accounts of space and time.
As one can ask whether there could be two extended objects that were not spatially related to each other, one can ask whether there could be two events that were not temporally related to each other.
One can ask whether space is a a real thing—a substance—a thing that exists independently of its inhabitants, or b a mere system of relations among those inhabitants.
And one can ask the same question about time. But there are also questions about time that have no spatial analogues—or at least no obvious and uncontroversial analogues.
There are, for example, questions about the grounds of various asymmetries between the past and the future—why is our knowledge of the past better than our knowledge of the future? There do not seem to be objective asymmetries like this in space.
In one way of thinking about time, there is a privileged temporal direction marking the difference between the past, present, and future. Times change from past to present to future, giving rise to passage. Presentist A-theorists, like Prior , deny that the past or future have any concrete reality. Presentists typically think of the past and future as, at best, akin to abstract possible worlds—they are the way the world was or will be, just as possible worlds are ways the actual world could be.
Other A-theorists, like Sullivan , hold that the present is metaphysically privileged but deny that there is any ontological difference between the past, present, and future. More generally, A-theorists often incorporate strategies from modal metaphysics into their theories about the relation of the past and the future to the present.
According to B-theories of time, the only fundamental distinction we should draw is that some events and times are earlier or later relative to others.
According to the B-theorists, there is no objective passage of time, or at least not in the sense of time passing from future to present and from present to past. B-theorists typically maintain that all past and future times are real in the same sense in which the present time is real—the present is in no sense metaphysically privileged. It is also true, and less often remarked on, that space raises philosophical questions that have no temporal analogues—or at least no obvious and uncontroversial analogues.
Why, for example, does space have three dimensions and not four or seven? On the face of it, time is essentially one-dimensional and space is not essentially three-dimensional. It also seems that the metaphysical problems about space that have no temporal analogues depend on the fact that space, unlike time, has more than one dimension.
For example, consider the problem of incongruent counterparts: those who think space is a mere system of relations struggled to explain our intuition that we could distinguish a world containing only a left hand from a world containing only a right hand. So it seems there is an intuitive orientation to objects in space itself. It is less clear whether the problems about time that have no spatial analogues are connected with the one-dimensionality of time. Finally, one can raise questions about whether space and time are real at all—and, if they are real, to what extent so to speak they are real.
Or was McTaggart's position the right one: that space and time are wholly unreal? If these problems about space and time belong to metaphysics only in the post-Medieval sense, they are nevertheless closely related to questions about first causes and universals. First causes are generally thought by those who believe in them to be eternal and non-local.
God, for example—both the impersonal God of Aristotle and the personal God of Medieval Christian, Jewish, and Muslim philosophy—is generally said to be eternal, and the personal God is said to be omnipresent. To say that God is eternal is to say either that he is everlasting or that he is somehow outside time.
And this raises the metaphysical question of whether it is possible for there to be a being—not a universal or an abstract object of some other sort, but an active substance—that is everlasting or non-temporal. An omnipresent being is a being that does not occupy any region of space not even the whole of it, as the luminiferous ether of nineteenth-century physics would if it existed , and whose causal influence is nevertheless equally present in every region of space unlike universals, to which the concept of causality does not apply.
The doctrine of divine omnipresence raises the metaphysical question whether it is possible for there to be a being with this feature. But it is doubtful whether this is a position that is possible for a metaphysician who says that a white thing is a bundle composed of whiteness and various other universals. All theories of universals, therefore, raise questions about how things in various ontological categories are related to space.
And all these questions have temporal analogues. Related to questions about the nature of space and time are questions about the nature of objects that take up space or persist through time, and these questions form yet another central theme in post-medieval metaphysics.
Are some or all objects composed of proper parts? Can more that one object be located in exactly the same region? Do objects persist through change by having temporal parts?
Much work on persistence and constitution has focused on efforts to address a closely knit family of puzzles—the puzzles of coincidence. Consider a gold statue. Many metaphysicians contend that there is at least one material object that is spatially co-extensive with the statue, a lump of gold. This is easily shown, they say, by an appeal to Leibniz's Law the principle of the non-identity of discernibles. There is a statue here and there is a lump of gold here, and—if the causal story of the statue's coming to be is of the usual sort—the lump of gold existed before the statue.
Or so these metaphysicians conclude. But it has seemed to other metaphysicians that this conclusion is absurd, for it is absurd to suppose these others say that there could be spatially coincident physical objects that share all their momentary non-modal properties.
Hence, the problem: What, if anything, is the flaw in the argument for the non-identity of the statue and the lump? Tibbles is a cat. Suppose Tail is cut off—or, better, annihilated.
Tibbles still exists, for a cat can survive the loss of its tail. But what will be the relation between Tib and Tibbles? Can it be identity? No, that is ruled out by the non-identity of discernibles, for Tibbles will have become smaller and Tib will remain the same size. But then, once again, we seem to have a case of spatially coincident material objects that share their momentary non-modal properties. Both these constitution problems turn on questions about the identities of spatially coincident objects—and, indeed, of objects that share all their proper parts.
A third famous problem of material constitution—the problem of the Ship of Theseus—raises questions of a different sort. Baker is a defense of this thesis. In addition to the intrinsic interest of metaphysical issues, some argue, metaphysical understanding is a prerequisite for reasoned appraisal of competing moral theories: one cannot engage in productive reflection on how people ought to be treated without an understanding of what people are. Similar points can be made about the relation of metaphysical reasoning to theology, to the sciences, and to the social sciences.
In this course, we will study and evaluate some important positions within the realist metaphysical tradition. For example, we will reflect on theories of substance, essence, natural kinds, universals and particulars, properties, and relations as elements of a theory of the nature of reality. We will consider objections to traditional metaphysics based on empiricism, scientism, nominalism, skepticism, and other positions.
In addition, we will discuss how fundamental metaphysical issues bear on selected particular questions, such as the existence and nature of God, the relation of mind and body, and freedom of the will.
Metaphysical realism as opposed to anti-realism is the theory that the world and at least some objects exist independently of our knowing of their existence and our conceptualization of them. It is a doctrine, not about what exists, but about what it is to exist. Influential in the ancient Greco-Roman world and dominant in the medieval era, it lost ground to anti-realism e.
In the 20 th century, realism began to be taken seriously again, although anti-realism remains dominant in the social sciences and in much popular culture. This course first explores realism and its commitments.
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