Presented at Merck Summer Institute for Bioethics

1. Material Constitution and Identity: A Primer for Metaphysics What are we doing hearing about metaphysics? Isn't this about synthetic biology? Yes, but... There are interesting metaphysical questions in synthetic biology: “ How do we determine identity conditions for hybrid organisms that are built of both natural and synthetic components and may have components that do not exist in the natural world, and do not function like anything in the natural world?” In other words, what the hell are we making in synthetic biology? When are these synthetic things members of some kind or the same kind? When do the things that are being made have ethically relevant properties – i.e., life, organismhood? Who owns the genetic recipe for a particular synthetic creation when the materials that constitute it and the laws for their combination existed long before it was put together by so and so?

2. For example, take some arbitrary, artificial nano-device, AND, (for delivering some DNA). AND is made of matter, atoms composing molecules, composing proteins, composing... The matter composing AND is identical with AND, right? AND just is the matter it is constituted of. AND and the quantity of matter that compose AND are identical the same way that a statue and the clay it is made from are identical. The following claims are true, at least intuitively: A. When the statue is rained on, the clay is rained on. B. When the clay is exposed to light, the statue is exposed to light. Similarly: C. When the atoms are outside, AND is outside. D. When AND is exposed to radiation, its atoms, its matter are exposed. And so on for a long list of predicates or properties. But AND can be destroyed by some event e (say, dissolution by enzyme X). However, the exact atoms that constitute AND aren't destroyed by such dissolution, they just get spread over an area larger than AND took up. The quantity of matter that made up AND still exists and AND doesn't.

3. How can it be that AND doesn't survive something that the quantity of matter making up AND does survive, when AND and that quantity of matter are identical? It is a feature of the concept of identity that if any two things are identical, what is true of one is true of the other. That's just what “identical” means! So, if AND and the quantity of matter (QOM) constituting it are identical, then anything that is true of AND must be true of QOM and vice versa. But the statement “survives dissolution by enzyme X” is false of AND and true of QOM! So AND and QOM are not identical. But that's crazy! That means that AND and QOM, two distinct, separate objects, were in the same space at the same time before AND was dissolved by enzyme X, and two things can't be in the same space at the same time! That's just a truism – it's a fact about the world that we take to be obviously true. This is an antinomy – an apparently sound argument that results in a conclusion that is obviously absurd.

4. So, synthetic biology has built in metaphysical problems. And these could spin out into more practical problems. Just one example: Who owns AND and who owns QOM? If I buy QOM, and someone comes up with a way to invent AND, who gets to keep it? If I own a house, and Shelly comes over and paints it or moves some parts of it around, does Shelly own the house? Or is the changed house a distinct object that Shelly owns while I own the original house? Who gets to live there? If AND and QOM are not identical, can I own one and not the other? If I own AND and QOM, do I still own QOM after AND has been dissolved? Do I have partial ownership of anything that uses parts of QOM afterward? The AND-QOM antinomy has the exact same structure as the classic Statue-Clay antinomy. In fact, there are many “paradoxes of identity” that share similar features.

5. Statue-Clay: On Monday, a sculptor buys a lump of clay. On Tuesday, the sculptor shapes it into a horse – the clay is now a statue of a horse. On Wednesday, the sculptor (inexplicably) gets tired of horses and smushes the still-soft statue back into a nondescript lump of clay. On Monday, the clay existed. On Tuesday, the statue and the clay existed. On Wednesday, the clay still exists, but the statue doesn't. Let's introduce variables (briefly) to talk about it. If x and y are identical, then everything true of x must be true of y. Now, let's substitute the statue for x and the lump of clay for y. If the statue and the clay are identical, then everything true of the statue must be true of the clay. It is true of the statue that smushing destroys it, but it is not true that smushing destroys the clay. So the statue and the clay are not identical! Dion and Theon: There is a normal Greek man named Dion. Imagine Dion without his right foot. This sum of “normal Greek man” parts is just like Dion in every detail except that he doesn't have a right foot – call him Theon. Because any two things must have all the same properties (all of the same predicative statements must be true of them), and Dion has a right foot while Theon doesn't, Dion and Theon are not identical.

6. Debtors' Paradox: Imagine Dion borrows money from you on Monday. On Tuesday, you come collecting, only to find out that he cut off his right foot. But now it is no longer true of Dion that he has a right foot. So Dion on Monday and Dion on Tuesday are not identical. In fact Dion on Tuesday takes up the exact same space as Theon on Monday. Is Dion just Theon now? And does Theon owe you anything? You can't collect a debt from someone that didn't borrow anything from you, and Dion on Monday is not identical with Dion on Tuesday or with Theon on Monday, and neither of them borrowed from you. Ship of Theseus: There is a famous ship (from some city, maybe it was Theseus). It is made from planks of wood harvested from a particular forest, A. Eventually, it is housed in a museum to preserve it. Over time, the planks rot and are replaced, one by one, with wood planks from a different forest, B. Eventually, the ship in the museum is made up of entirely B-planks. Is this the same ship as the original? It is not true that the original ship was made of B-planks, but it is true of the ship in the museum that it is made of B-planks. Vice versa for A-planks. The A-planks are in a different place than the original ship, so the original ship is not identical with the planks that made it up.

7. These four situations all produce an antinomy because the conclusions that we are compelled to draw from them are inconsistent with the obvious truth that no two, distinct objects can occupy the same space at the same time. Let's call this... The One Object to a Space Principle (OOSP) : If two objects, x and y, are not identical, it is impossible for them to occupy the same space at the same time. In the Statue-Clay scenario, the statue, x, and and the lump of clay, y, are in the same place at the same time. In the Dion-Theon case, Dion and Theon are in the same place at the same time. A further crazy-sounding consequence results in the Debtor's paradox: Dion is destroyed by cutting off his right foot, and Theon survives. Dion and Theon have different “persistence conditions” - they survive under different conditions. Until Dion cuts off his right foot, Dion and Theon exist in the same space at the same time. In the Ship case, the A-planks are in a different place than the original ship after the replacement. Before, they are in the same space as the original ship.

8. We have good reasons to believe in the four non-identity theses. And OOSP is obviously true. Obviously. This is trouble. The non-identity theses can't be true if OOSP is true and vice versa. So what can we do? First, it helps to focus on one case. It reduces the amount of information we have to juggle. Let's focus on the Statue-Clay case, because it has the basic form that we are looking for. The argument leading us to believe that the state and the clay are not identical is this: 1. A lump of clay L exists on Monday, exists on Tuesday, and exists on Wednesday. 2. A statue S does not exist on Monday, exists on Tuesday, and does not exist on Wednesday. 3. For any two objects, x and y, if they are identical, then x and y share all of the same properties (everything true of x is true of y and vice versa). C. S and L are not identical. (Modus Tollens) And S and L exist in the same space on Tuesday. *Absurd! The conjunction of the conclusion of the argument and the fact that S and L are in the same place conflicts with OOSP.

9. The first thing to notice is that there are assumptions underlying the previous argument: Creation : It is assumed that the statue really comes into existence when the sculptor sculpts the clay and it really didn't exist before. Survival : It is assumed that the clay continues to exist after it has been sculpted into the statue. Existence : It is assumed that both statues and lumps of clay really exist. Absurdity : It is assumed the OOSP is true, so the conclusion of the argument is false. Leibniz' Law (the law of indiscernability of identicals): x is identical to y only if everything that is true of x is true of y and vice versa (Or, more naturally but circularly: x and y are identical only if they have exactly the same properties.)

10. Depending on what assumption we reject, we get a different solution to the antinomy. Reject Absurdity -> Cohabitation Theory or Coincidence of Objects Theory Reject Creation -> Just-Matter Theory Reject Existence -> Eliminativism/Nihilism Reject Survival -> Takeover Theory Reject Liebniz' Law -> Relative Identity Theory

11. Rejecting Absurdity -> Cohabitation Theory or Coincidence of Objects Theory (Let's call it COT). OOSP is false. It turns out that more than one object CAN occupy the same space at the same time. The clay and the statue are two separate objects that occupy the same space at the same time. We can prove they're not identical. The same goes for a book and the quantity of paper that make it up. And a table and the quantity of wood that make it up. Everywhere we think we see a single object, we actually see at least two: the object and the amount of matter that constitute it. The other assumptions of the antinomy actually constitute an argument against OOSP.

12. Reasons to accept COT: The arguments for the non-identity of familiar objects and their matter can be stated in something like a general form like so: P1. Liebniz' Law: for all x, if x=y, then Px implies Py. P2. For just about any object in any space at any time, we can show that the quantity of matter constituting it, which is in the same space at the same time, has different properties or that not everything true of the object is true of the matter constituting it. C. For any object, in any space, at any time, we can show that the quantity of matter constituting it is not identical to the object proper. Defending P1: This is a fundamental assumption of the logic of identity and just what the word “identical” means. Defending P2: - Persistence conditions i.) x is destroyed by an event e ii.) the quantity of matter making up x is not destroyed by an event e - Historical properties iii.) x did not exist at t1, does exist at t2, and does not exist at t3 iv.) the quantity of matter making up x existed at t1, existed at t2, and existed at t3

13. These pairs of statements can be substituted into for most arbitrary objects, so most objects are not identical to the matter making them up. COT resolves the antinomy by just removing one of the two ideas that are in conflict. Reasons not to accept COT: 1. The Explosion of Reality(!): We can come up with an infinite number of properties that could separate things that are intuitively not separate objects. Imagine a statue outdoors and a statue indoors. The statue, when it is outdoors has the property “being outdoors”. The statue, while indoors, has the property “being indoors”. By using the argument form above, we can say that the statue-while-outdoors (outstatue) is not identical to the statue-while-indoors (instatue). And so on for anything that can ever happen to a statue. The laptop in front of me is not just a laptop, but a quantity of laptop matter, a sum of laptop parts, an in-laptop, a table-laptop, a Ralph-laptop, a lit-laptop, a … If we want to rule out some of those objects as absurd, we need a reason for it. Why rule out in-laptops and lit-laptops? Is there a reason to rule these other objects out other that isn't anthropocentric?

14. 2. Impenetrability: Try walking through a wall or a table or a laptop. You can't occupy the same space! Toss a baseball at a tv. No occupying the same space! OOSP is just true! 3. Extensionality: a response to impenetrability is that the wall and I aren't made of the same parts. If we were, there would be no problem. Sometimes two objects are made of the same matter. No problem. But that leads to the Extensionality problem: How can two things with exactly the same parts be different objects or have different properties? Normally, what parts a thing is made of is what allows us to tell it apart from other things – the difference between a beef hamburger and a veggie burger. Or, think of a house painted red and a house made of the same parts in the same place painted green. It's the same house, but a different color... isn't it? 4. Grounding: normally, we think of some properties being “dependent” on other properties. The kinds of properties that are different between statues and clay are “non-categorical” properties. The properties they share are “categorical” properties. We think of non-categorical properties being dependent on or “grounded” in categorical properties. How can this grounding relation allow for different non-categorical properties to be grounded in the same categorical properties? Is grounding a completely indeterministic relation?

15. So, there are good reasons not to accept COT and to keep accepting OOSP. What are our other options? Reject Creation -> The Just-Matter Theory (JMT) “ Turns out, just hunks.” - Steve Brule The JMT says that the statue is not created when the clay is sculpted. We really ought to identify the statue with the quantity or “hunk” of matter it is made of from the very beginning – and that matter existed long before the sculpting. The statue is never actually created – it just is the hunk of matter that eventually makes it up and it has whatever properties the hunk of matter has at any given time. It's also incredibly rare that matter is destroyed, too. Since the statue is identified with the hunk of matter, the statue actually survives anything that the hunk of matter survives, including smashing, exploding, and being strewn across the galaxy. And the antinomy is avoided because there is only the hunk of matter in statue form or in clay form or in some form in any space at a given time.

16. Reject Existence -> Eliminativism/Nihilism (EN) EN rejects the Creation assumption implicitly by rejecting the Existence assumption. Statues and tables and people don't exist – of course they're never created. Rather than identifying objects with the hunk of matter they are made of, we should just say that, strictly speaking, there are no objects at all, there are only objectlike configurations of basic things that do exist – of matter. Reduce objects to the fundamental particles that make them up. There is no additional entity that exists in addition to the particles. The antinomy doesn't come up because there aren't multiple objects in the same space, there are just n fundamental particles distributed about a certain area. Both JMT and EN say that all of the properties of objects are explained by the fundamental things that objects are made of. The only disagreement is over whether we should talk about those objects existing in a literal or a figurative sense. (The difference between JMT and EN is held by some to be merely verbal – a disagreement about whether the statement “statues exist” is true that depends on language more than on the way the world is. The view that the entire debate about identity conditions is all just a verbal mess is called Deflationism. It's complicated, I'm going to skip it.)

17. Reasons for accepting JMT and EN: The views are suggested by the success that physical science has had reducing things to configurations of matter. We just supplement the idea of everything being made of matter by identifying certain quantities of matter with objects that we are more familiar with or eliminating those familiar objects from the category of things that really exist. Either seemingly resolves the antinomy. A potential objection to both views might be that objects both exist and are created and destroyed. Isn't that obvious? To say that objects never come into our out of being, either because they exist wherever their matter is or because they never actually exist is equally absurd as denying OOSP. I can see and feel objects and watch them take shape and lose it. JMT/EN proponents can respond by saying that that doesn't mean that there are objects “over and above” the objectlike configurations of particles or quantities of matter. Sensory evidence does not distinguish between n fundamental particles and n particles plus the object itself. Just like sensory evidence doesn't tell between being on Earth or being a brain in a vat.

18. Reasons for rejecting JMT: If objects just are the hunks of matter they are made of, then not only are they not created by changing shape, they are not destroyed. This is problematic. The statue survives being smashed? What about a person? Does a person survive a dramatic change in the hunk of matter that makes it up like exploding or otherwise dying? Socrates died thousands of years ago and his matter is dispersed. The Just-Matter theory implies that Socrates is still around. The hunk of matter making up Socrates still exists, it is just in a different configuration – dispersed throughout the earth. So, if Socrates just is that hunk of matter, Socrates still exists, just dispersed around the earth. Similarly, the quantity of matter making up me has existed for at least thousands of years, it was just never in a configuration that resulted in a person walking around and making powerpoints until recently. But it still existed. If I am that hunk of matter, then I have existed for thousands of years, just in a different shape. But, both of these conclusions are just about as absurd as the idea that two things can occupy the same space at the same time, so a theory that entails them is no better alternative.

19. Reasons to reject EN: Even though sensory evidence can't directly show that EN is false, it is still hard to swallow – as hard as the idea of more than one object to a space – and that counts against it. There may not be fundamental particles. Physical science has progressively unveiled level upon level of increasingly tiny, increasingly fundamental particles. Molecules gave way to atoms, which gave way to subatomic particles, which gave way to quarks. Suppose that goes on forever. EN is committed to denying everything but fundamental particles, if there are none, then EN denies everything – which is much more absurd than Cohabitation.

20. Rejecting Survival -> Takeover Theory (TT) Since OOSP states that it is absurd that more than one object can occupy the same space, we can resolve the antinomy by supposing that the clay ceases existing when the statue begins existing. This is the Takeover Theory. The statue takes over the quantity of matter that was the clay. At 3pm, a hunk of matter x satisfies predicates p1-pn. At 4pm, some changes have taken place and x no longer satisfies some of p1-pn. So, x-at-3pm and x-at-4pm are not identical, but there is just x-at-4pm because x-at-4pm takes over the matter that x-at-3pm previously had “control” over. The change destroyed x-at-3pm and x-at-4pm replaces it. The rearranged fundamental parts constitute different objects at different times depending on their arrangement. No antinomy! There is only one object at any given time in any given space. What determines whether a particular object takes over a lump of matter after an event or a change depends on the kind of object that the matter was just prior (the “dominant kind” of object). A lump of matter controlled by statue-kind (arranged so that it is a statue) must retain statue shape or else something else takes over. A lump of matter controlled by person-kind could be taken over by corpse-kind if certain changes happen to it.

21. Reasons to accept TT: Solves the antinomy. Allows for creation and destruction in the statue-clay case, which are intuitively plausible. Is somewhat consistent with physical science – fundamental particles in configurations exist and the nature of these configurations determines what properties the resulting objects have. Reasons to reject TT: It's highly implausible that a lump of clay can be destroyed by an act like sculpting it into a statue. Even with the rule about kinds determining persistence conditions, it's unclear when a change or event destroys an object because it's unclear when one kind is dominant over another. Weird cases: Imagine that we start treating a rock like a work of art – displaying it in galleries, writing essays about it. If this makes the rock a piece of art, then it destroys the rock. But how can looking at and talking about a rock in a certain way destroy a rock?

22. Rejecting OOSP (again) -> Four Dimensionalism (4-D) Return to Cohabitation/Coincidence of Objects Theory. The problems with COT were impenetrability, the explosion of reality, extensionality, and grounding objections. We can answer some objections to COT with 4-D. Maybe that makes the 4-D version of COT worth believing. Time is like space – objects can have parts in different locations in space and in time. My arm is in a different location than my nose. The legs of the table are in a different space than the table top. 4-D just holds that one object can have different parts in time. We call different parts different objects. The statue is just the temporal part of the clay that is statue shaped. The clay has other parts too – temporal parts where it is lump shaped. Reasons to accept 4-D: The argument for COT. Accept the response to impenetrability, and then resist the extensionality problem.

23. 4-D resolves the extensionality problem by saying that objects are distinguished by their parts – including their temporal parts. The clay and the statue don't have the exact same parts – the statue is the temporal part part of the clay that is statue shaped and the clay is made of the statue-shaped temporal parts and the lump-shaped temporal parts. 4-D could solve the grounding problem by saying that the difference in non-categorical properties of the statue and the lump are grounded in the fact that they are different temporal parts. I'm not sure what this means. Reasons to reject 4-D: 4-D doesn't resolve the Explosion problem, it accepts it. In fact, 4-D takes Explosion farther. Each change takes place over time and each instant of time is a new temporal part. In fact, we can think of arbitrary temporal parts. We can carve up any object into 14 second long temporal parts. This is still an absurd conclusion, and there is no nonanthropocentric and intuitive way of ruling out new temporal parts, each of which is a new object. If this is implausible, it counts against 4-D. Also, there is the chance that the image of time being like space might fail in favor of another image. Maybe it's just not right to think of time like space. Lumpl and Goliath. Two objects with all of the same temporal parts.

24. Rejecting Liebniz' Law -> Relative Identity Theory (RIT) There is no absolute identity relation, identity is only a relative relation – relative to kinds. A statue is the same statue as the lump of clay and the same clay as the lump of clay. There is no reason to think they ought to have all of the same properties as each other – they each need to only have the properties of the kind they are both associated with. More generally: x is the same F as y and y is the same F as x, but x and y are different Gs, and it doesn't make sense to just say that “x is the same as y”. Think of the Debtors' paradox: Dion is the same kind, person, as Theon even though they are distinct in other ways – they have different masses, they have different lists of parts. Reasons to accept RIT: It solves some problems quickly and to intuitive satisfaction; the statue-clay, the debtors, Dion-Theon... and all problems with their exact structure.

25. Reasons to reject RIT: RIT rejects seemingly basic concepts of identity. Rejecting Liebniz' Law is intuitively just as absurd as rejecting the idea that two objects can't be in the same space at the same time. In fact, Liebniz' Law has had a very respectable place in logic and semantics. It might be stronger than OOSP. In predicate logic with identity, identity is defined by 4 axioms: Reflexivity: For all x, x = x Symmetry: For all x and all y, if x= y, then y = x Transitivity: For all x and all y and all z, if x= y, and y = z, then x = z. Substitutivity: For all x and all y, if x = y, then if x is F, y is F That is, Liebniz' Law is successfully captured in logic, and it is pretty useful, but RIT has us reject it. Further, on RIT's account, it makes no sense to say that A = B. First, it does make sense to us normally. Second, a major part of set theory is the axiom of extensionality. If sets A and B have the same members, they are identical sets. And they are not different Gs! We must make sense of whether or not a set A is plain old identical to a set B or whether a member x of a set is the same member as y (and not a different G) or else revise set theory a lot.

26. Take home points: There is an antinomy – apparently sound argument that leads to an obviously false conclusion or that is inconsistent with something that seems obviously true. The crucial idea: The keys to resolving the antinomy are i.) knowing that there are assumptions underlying the antinomy and ii.) systematically and carefully thinking about what is being assumed and how those assumptions inferentially relate to the conclusions. Exposing the assumptions requires figuring out how they support the inconsistent statements. But... rejecting some of the assumptions will have consequences, and this is what distinguishes the various theories of identity. We have to figure out which consequences we are willing to live with and which ones we aren't. These ideas hold for just about everything that can be debated. It's good to carefully think about the assumptions and inferential connections for any problem.

27. Bibliography : Ted Sider. (2005) Riddles of Existence Ryan Wasserman. (2009) “Material Constitution” Stanford Encyclopedia of Philosophy Harold Noonan. (2009) “Identity” SEP Harry Dutsch. (2007) “Relative Identity” SEP Achille Varzi. (2009) “Mereology” SEP John Pollock. (1990) Technical Methods in Philosophy W.V. Quine. (1950) Methods of Logic Ernie Lepore (2000) Meaning and Argument

28. First-hand reading: 4-Dimensionalism: Ted Sider. (2001) Four Dimensionalism David Lewis (1976) “ Survival and Identity” Ed. A. Rorty. The Identities of Persons. Takeover Theory (Dominant Kinds): Micheal Burke (1997) “Preserving the Idea of One Object to a Place...” Ed. Micheal Rea. Material Constitution . Explosion of Reality: Eli Hersch. (1982) The Concept of Identity. Ernest Sosa (1987) “Subjects Among Other Things” Ed. J.E. Tomberlin. Philosophical Perspectives. Eliminativism/Nihilism: Trenton Merrick (2001) Objects and Persons. Peter Unger (1979) “There are No Ordinary Things” Synthese . Peter van Inwagen (1990) Material Beings. Just-Matter Theory: Roderick Chisolm (1976) Person and Object. Cohabitation/Coincident Objects: David Wiggins (1968) Identity and Spatio-Temporal Continuity. David Lewis (1976) “Survival and Identity” Ed. A. Rorty. Identities of Persons. Relative Identity: Peter Geach (1967) “Identity” Review of Metaphysics. Deflationism: Rudolf Carnap (1950) “Empiricism, Semantics, Ontology” International Review of Philosophy.