Form is Not Matter

I have touched on this at other times, as here, here, and here. In the present post I am simply emphasizing the point more directly potentially for future reference.

If you receive an IKEA table in the mail, you have the parts that go to make up a table, but they are not yet put together in the form of a table. But very obviously, the form is not an additional part that you need to make the table. One does not say, “We need six parts for the table: the four legs, the tabletop, and the form of the table.” The form is something additional, but it is not an additional part. It is the “being put together as a table” that the parts require in order to be a table.

To say that the parts exist “in the form of a table” is also an informative expression here. One speaks as though “the form of a table” were a place, somewhat like Newton’s absolute space, in which the parts of the table exist together. This idea is helpful because just as Newton’s absolute space does not actually exist, so there will be analogous errors about form, as for example the idea that form is an additional part. Likewise, understanding the actual truth about place will help us to understand the truth about form.

Zeal for Form, But Not According to Knowledge

Some time ago I discussed the question of whether the behavior of a whole should be predictable from the behavior of the parts, without fully resolving it. I promised at the time to revisit the question later, and this is the purpose of the present post.

In the discussion of Robin Hanson’s book Age of Em, we looked briefly at his account of the human mind. Let us look at a more extended portion of his argument about the mind:

There is nothing that we know of that isn’t described well by physics, and everything that physicists know of is well described as many simple parts interacting simply. Parts are localized in space, have interactions localized in time, and interactions effects don’t move in space faster than the speed of light. Simple parts have internal states that can be specified with just a few bits (or qubits), and each part only interacts directly with a few other parts close in space and time. Since each interaction is only between a few bits on a few sides, it must also be simple. Furthermore, all known interactions are mutual in the sense that the state on all sides is influenced by states of the other sides.

For example, ordinary field theories have a limited number of fields at each point in space-time, with each field having a limited number of degrees of freedom. Each field has a few simple interactions with other fields, and with its own space-time derivatives. With limited energy, this latter effect limits how fast a field changes in space and time.

As a second example, ordinary digital electronics is made mostly of simple logic units, each with only a few inputs, a few outputs, and a few bits of internal state. Typically: two inputs, one output, and zero or one bits of state. Interactions between logic units are via simple wires that force the voltage and current to be almost the same at matching ends.

As a third example, cellular automatons are often taken as a clear simple metaphor for typical physical systems. Each such automation has a discrete array of cells, each of which has a few possible states. At discrete time steps, the state of each cell is a simple standard function of the states of that cell and its neighbors at the last time step. The famous “game of life” uses a two dimensional array with one bit per cell.

This basic physics fact, that everything is made of simple parts interacting simply, implies that anything complex, able to represent many different possibilities, is made of many parts. And anything able to manage complex interaction relations is spread across time, constructed via many simple interactions built up over time. So if you look at a disk of a complex movie, you’ll find lots of tiny structures encoding bits. If you look at an organism that survives in a complex environment, you’ll find lots of tiny parts with many non-regular interactions.

Physicists have learned that we only we ever get empirical evidence about the state of things via their interactions with other things. When such interactions the state of one thing create correlations with the state of another, we can use that correlation, together with knowledge of one state, as evidence about the other state. If a feature or state doesn’t influence any interactions with familiar things, we could drop it from our model of the world and get all the same predictions. (Though we might include it anyway for simplicity, so that similar parts have similar features and states.)

Not only do we know that in general everything is made of simple parts interacting simply, for pretty much everything that happens here on Earth we know those parts and interactions in great precise detail. Yes there are still some areas of physics we don’t fully understand, but we also know that those uncertainties have almost nothing to say about ordinary events here on Earth. For humans and their immediate environments on Earth, we know exactly what are all the parts, what states they hold, and all of their simple interactions. Thermodynamics assures us that there can’t be a lot of hidden states around holding many bits that interact with familiar states.

Now it is true that when many simple parts are combined into complex arrangements, it can be very hard to calculate the detailed outcomes they produce. This isn’t because such outcomes aren’t implied by the math, but because it can be hard to calculate what math implies. When we can figure out quantities that are easier to calculate, as long as the parts and interactions we think are going on are in fact the only things going on, then we usually see those quantities just as calculated.

The point of Robin’s argument is to take a particular position in regard to the question we are revisiting in this post: everything that is done by wholes is predictable from the behavior of the parts. The argument is simply a more extended form of a point I made in the earlier post, namely that there is no known case where the behavior of a whole is known not to be predictable in such a way, and many known cases where it is certainly predictable in this way.

The title of the present post of course refers us to this earlier post. In that post I discussed the tendency to set first and second causes in opposition, and noted that the resulting false dichotomy leads to two opposite mistakes, namely the denial of a first cause on one hand, and to the assertion that the first cause does or should work without secondary causes on the other.

In the same way, I say it is a false dichotomy to set the work of form in opposition with the work of matter and disposition. Rather, they produce the same thing, both according to being and according to activity, but in different respects. If this is the case, it will be necessarily true from the nature of things that the behavior of a whole is predictable from the behavior of the parts, but this will happen in a particular way.

I mentioned an example of the same false dichotomy in the post on Robin’s book. Here again is his argument:

But consider a key question: Does this other feeling stuff interact with the familiar parts of our world strongly and reliably enough to usually be the actual cause of humans making statements of feeling like this?

If yes, this is a remarkably strong interaction, making it quite surprising that physicists have missed it so far. So surprising in fact as to be frankly unbelievable. If this type of interaction were remotely as simple as all the interactions we know, then it should be quite measurable with existing equipment. Any interaction not so measurable would have be vastly more complex and context dependent than any we’ve ever seen or considered. Thus I’d bet heavily and confidently that no one will measure such an interaction.

But if no, if this interaction isn’t strong enough to explain human claims of feeling, then we have a remarkable coincidence to explain. Somehow this extra feeling stuff exists, and humans also have a tendency to say that it exists, but these happen for entirely independent reasons. The fact that feeling stuff exists isn’t causing people to claim it exists, nor vice versa. Instead humans have some sort of weird psychological quirk that causes them to make such statements, and they would make such claims even if feeling stuff didn’t exist. But if we have a good alternate explanation for why people tend to make such statements, what need do we have of the hypothesis that feeling stuff actually exists? Such a coincidence seems too remarkable to be believed.

I am currently awake and conscious, hearing the sounds of my keyboard as I type and the music playing in the background. Robin’s argument is something like this: why did I type the previous sentence? Is it because I am in fact awake and conscious and actually heard these sounds? If in principle it is predictable that I would have typed that, based on the simple interactions of simple parts, that seems to be an entirely different explanation. So either one might be the case or the other, but not both.

We have seen this kind of argument before. C.S. Lewis made this kind of argument when he said that thought must have reasons only, and no causes. Similarly, there is the objection to the existence of God, “But it seems that everything we see in the world can be accounted for by other principles, supposing God did not exist.” Just as in those cases we have a false dichotomy between the first cause and secondary causes, and between the final cause and efficient causes, so here we have a false dichotomy between form and matter.

Let us consider this in a simpler case. We earlier discussed the squareness of a square. Suppose someone attempted to apply Robin’s argument to squares. The equivalent argument would say this: all conclusions about squares can be proved from premises about the four lines that make it up and their relationships. So what use is this extra squareness? We might as well assume it does not exist, since it cannot explain anything.

In order to understand this one should consider why we need several kinds of cause in the first place. To assign a cause is just to give the origin of a thing in a way that explains it, while explanation has various aspects. In the linked post, we divided causes into two, namely intrinsic and extrinsic, and then divided each of these into two. But consider what would happen if we did not make the second division. In this case, there would be two causes of a thing: matter subject to form, and agent intending an end. We can see from this how the false dichotomies arise: all the causality of the end must be included in some way in the agent, since the end causes by informing the agent, and all the causality of the form must be included in some way in the matter, since the form causes by informing the matter.

In the case of the square, even the linked post noted that there was an aspect of the square that could not be derived from its properties: namely, the fact that a square is one figure, rather than simply many lines. This is the precise effect of form in general: to make a thing be what it is.

Consider Alexander Pruss’s position on artifacts. He basically asserted that artifacts do not truly exist, on the grounds that they seem to be lacking a formal cause. In this way, he says, they are just a collection of parts, just as someone might suppose that a square is just a collection of lines, and that there is no such thing as squareness. My response there was the same as my response about the square: saying that this is just a collection cannot explain why a square is one figure, nor can the same account explain the fact that artifacts do have a unity of some kind. Just as the denial of squareness would mean the denial of the existence of a unified figure, so the denial of chairness would mean the denial of the existence of chairs. Unlike Sean Carroll, Pruss seems even to recognize that this denial follows from his position, even if he is ambivalent about it at times.

Hanson’s argument about the human mind is actually rather similar to Pruss’s argument about artifacts, and to Carroll’s argument about everything. The question of whether or not the fact that I am actually conscious influences whether I say that I am, is a reference to the idea of a philosophical zombie. Robin discusses this idea more directly in another post:

Carroll inspires me to try to make one point I think worth making, even if it is also ignored. My target is people who think philosophical zombies make sense. Zombies are supposedly just like real people in having the same physical brains, which arose the through the same causal history. The only difference is that while real people really “feel”, zombies do not. But since this state of “feeling” is presumed to have zero causal influence on behavior, zombies act exactly like real people, including being passionate and articulate about claiming they are not zombies. People who think they can conceive of such zombies see a “hard question” regarding which physical systems that claim to feel and otherwise act as if they feel actually do feel. (And which other systems feel as well.)

The one point I want to make is: if zombies are conceivable, then none of us will ever have any more relevant info than we do now about which systems actually feel. Which is pretty much zero info! You will never have any info about whether you ever really felt in the past, or will ever feel in the future. No one part of your brain ever gets any info from any other part of your brain about whether it really feels.

These claims all follow from our very standard and well-established info theory. We get info about things by interacting with them, so that our states become correlated with the states of those things. But by assumption this hypothesized extra “feeling” state never interacts with anything. The actual reason why you feel compelled to assert very confidently that you really do feel has no causal connection with whether you actually do really feel. You would have been just as likely to say it if it were not true. What could possibly be the point of hypothesizing and forming beliefs about states about which one can never get any info?

We noted the unresolved tension in Sean Carroll’s position. The eliminativists are metaphysically correct, he says, but they are mistaken to draw the conclusion that the things of our common experience do not exist. The problem is that given that he accepts the eliminativist metaphysics, he can have no justification for rejecting their conclusions. We can see the same tension in Robin Hanson’s account of consciousness and philosophical zombies. For example, why does he say that they do not “make sense,” rather than asking whether or not they can exist and why or why not?

Let us think about this in more detail. And to see more clearly the issues involved, let us consider a simpler case. Take the four chairs in Pruss’s office. Is it possible that one of them is a zombie?

What would this even mean? In the post on the relationship of form and reality, we noted that asking whether something has a form is very close to the question of whether something is real. I really have two hands, Pruss says, if my hands have forms. And likewise chairs are real chairs if they have the form of a chair, and if they do not, they are not real in the first place, as Pruss argues is the case.

The zombie question about the chair would then be this: is it possible that one of the apparent chairs, physically identical to a real chair, is yet not a real chair, while the three others are real?

We should be able to understand why someone would want to say that the question “does not make sense” here. What would it even be like for one of the chairs not to be a real chair, especially if it is posited to be identical to all of the others? In reality, though, the question does make sense, even if we answer that the thing cannot happen. In this case it might actually be more possible than in other cases, since artifacts are in part informed by human intentions. But possible or not, the question surely makes sense.

Let us consider the case of natural things. Consider the zombie oak tree: it is physically identical to an oak tree, but it is not truly alive. It appears to grow, but this is just the motion of particles. There are three positions someone could hold: no oak trees are zombie oaks, since all are truly alive and grow; all oak trees are zombies, since all are mere collections of particles; and some are alive and grow, while others are zombies, being mere collections of particles.

Note that the question does indeed make sense. It is hard to see why anyone would accept the third position, but if the first and second positions make sense, then the third does as well. It has an intelligible content, even if it is one that we have no good arguments for accepting. The argument that it does not make sense is basically the claim that the first and second positions are not distinct positions: they do not say different things, but the same thing. Thus the the third would “not make sense” insofar as it assumes that the first and second positions are distinct positions.

Why would someone suppose that the first and second positions are not distinct? This is basically Sean Carroll’s position, since he tries to say both that eliminativists are correct about what exists, but incorrect in denying the existence of common sense things like oak trees. It is useful to say, “oak trees are real,” he says, and therefore we will say it, but we do not mean to say something different about reality than the eliminativists who say that “oak trees are not real but mere collections of particles.”

But this is wrong. Carroll’s position is inconsistent in virtually the most direct possible way. Either oak trees are real or they are not; and if they are real, then they are not mere collections of particles. So both the first and second positions are meaningful, and consequently also the third.

The second and third positions are false, however, and the meaningfulness of this becomes especially clear when we speak of the human case. It obviously does make sense to ask whether other human beings are conscious, and this is simply to ask whether their apparent living activities, such as speaking and thinking, are real living activities, or merely apparent ones: perhaps the thing is making sounds, but it is not truly speaking or thinking.

Let us go back to the oak tree for a moment. The zombie oak would be one that is not truly living, but its activities, apparently full of life, are actually lifeless. In order to avoid this possibility, and out of a zeal for form which is not according to knowledge, some assert that the activities of an oak cannot be understood in terms of the activities of the parts. There is a hint of this, perhaps, in this remark by James Chastek:

Consciousness is just the latest field where we are protesting that something constitutes a specific difference from some larger genus, but if it goes the way the others have gone, in fifty years no one will even remember the controversy or bother to give the fig-leaf explanations of it being emergent or reductive. No one will remember that there is a difference to explain. Did anyone notice in tenth-grade biology that life was explained entirely in terms of non-living processes? No. There was nothing to explain since nothing was noticed.

Chastek does not assert that life cannot be “explained entirely in terms of non-living processes,” in the manner of tenth-grade biology, but he perhaps would prefer that it could not be so explained. And the reason for this would be the idea that if everything the living thing does can be explained in terms of the parts, then oak trees are zombies after all.

But this idea is mistaken. Look again at the square: the parts explain everything, except the fact that the figure is one figure, and a square. The form of a square is indeed needed, precisely in order that the thing will actually be a whole and a square.

Likewise with the oak. If an oak tree is made out of parts, then since activity follows being, it should be unsurprising that in some sense its activities themselves will be made out of parts, namely the activities of its parts. But the oak is real, and its activities are real. And just as oaks really exist, so they really live and grow; but just as the living oak has parts which are not alive in themselves, such as elements, so the activity of growth contains partial activities which are not living activities in themselves. What use is the form of an oak, then? It makes the tree really an oak and really alive; and it makes its activities living activities such as growth, rather than being merely a collection of non-living activities.

We can look at human beings in the same way, but I will leave the details of this for another post, since this one is long enough already.

Form and Reality

The ordinary sentence “There are four chairs in my office” is true (in its ordinary context). Furthermore, its being true tells us very little about fundamental ontology. Fundamental physical reality could be made out of a single field, a handful of fields, particles in three-dimensional space, particles in ten-dimensional space, a single vector in a Hilbert space, etc., and yet the sentence could be true.

An interesting consequence: Even if in fact physical reality is made out of particles in three-dimensional space, we should not analyze the sentence to mean that there are four disjoint pluralities of particles each arranged chairwise in my office. For if that were what the sentence meant, it would tell us about which of the fundamental physical ontologies is correct. Rather, the sentence is true because of a certain arrangement of particles (or fields or whatever).

If there is such a broad range of fundamental ontologies that “There are four chairs in my office” is compatible with, it seems that the sentence should also be compatible with various sceptical scenarios, such as that I am a brain in a vat being fed data from a computer simulation. In that case, the chair sentence would be true due to facts about the computer simulation, in much the way that “There are four chairs in this Minecraft house” is true. It would be very difficult to be open to a wide variety of fundamental physics stories about the chair sentence without being open to the sentence being true in virtue of facts about a computer simulation.

But now suppose that the same kind of thing is true for other sentences about physical things like tables, dogs, trees, human bodies, etc.: each of these sentences can be made true by a wide array of physical ontologies. Then it seems that nothing we say about physical things rules out sceptical scenarios: yes, I know I have two hands, but my having two hands could be grounded by facts about a computer simulation. At this point the meaningfulness of the sceptical question whether I know I am not a brain in a vat is breaking down. And with it, realism is breaking down.

I am not completely sure what Pruss means by “realism is breaking down,” but he is looking at something important here. One question that needs to be addressed, however, is what counts as a skeptical scenario in the first place. In the rest of the post, Pruss makes an interesting suggestion about this:

In order for the sceptical question to make sense, we need the possibility of saying things that cannot simply be made true by a very wide variety of physical theories, since such things will also be made true by computer simulations. This gives us an interesting anti-reductionist argument. If the statement “I have two hands” is to be understood reductively (and I include non-Aristotelian functionalist views as reductive), then it could still be literally true in the brain-in-a-vat scenario. But if anti-reductionism about hands is true, then the statement wouldn’t be true in the brain-in-a-vat scenario. And so I can deny that I am in that scenario simply by saying “I have two hands.”

But maybe I am moving too fast here. Maybe “I have two hands” could be literally true in a brain-in-a-vat scenario. Suppose that the anti-reductionism consists of there being Aristotelian forms of hands (presumably accidental forms). But if, for all we know, the form of a hand can inform a bunch of particles, a fact about a vector or the region of a field, then the form of a hand can also inform an aspect of a computer simulation. And so, for all we know, I can literally and non-reductively have hands even if I am a brain in a vat. I am not sure, however, that I need to worry about this. What is important is form, not the precise material substrate. If physical reality is the memory of a giant computer but it isn’t a mere simulation but is in fact informed by a multiplicity of substantial and accidental forms corresponding to people, trees, hands, hearts, etc., and these forms are real entities, then the scenario does not seem to me to be a sceptical scenario.

A skeptical scenario, according to Pruss, is a situation where the things we normally talk about do not have forms. If they do have forms, we are not in a skeptical scenario at all, even if in some sense we are in a computer simulation or even if someone is a brain in a vat. On the face of it this seems a very odd claim: “form” seems to be a technical philosophical explanation, while asking if we are in a skeptical scenario seems to be asking if our everyday common sense understanding of things is mistaken.

Nonetheless, there is a lot of truth in his explanation. First let us consider what is meant by a skeptical scenario in the first place. In terms of his example, it is supposed to go something like this: “Is it possible that you are a brain in a vat without realizing it? If so, then almost everything you believe is false, since you do not have hands, the people you speak to are not real, and so on.”

In the post Pruss is pointing out a problem with the skeptical question. The skeptical question is like a skeptic in the remote past asking, “Is it possible that the earth is spinning without us realizing it? If so, then our everyday opinion that the sun rises every morning is false, since the sun does not move.”

The response to the second skeptic is evident: our everyday opinion that the sun rises every morning is not false, not even if the earth turns out to be spinning, because “the sun rises every morning,” is to be understood in whatever way is needed in order for it to be true. It refers to what happens every morning, whatever that actually happens to be.

Pruss is pointing out that we can answer the first question in the same way: our everyday opinion that we have hands is not false, not even if we are in a computer simulation or in a vat, because “I have two hands” is to be understood in whatever way is needed in order for it to be true. It refers to these two things in front of me right now, whatever they actually are.

Let’s suppose the skeptic tries to come up with a response. He might say, “Look, computer programs do not have hands, and brains do not have hands. So if you are a computer program or a brain in a vat, then you just do not have hands, period. So those scenarios do indeed mean that your common understanding would be false.”

It is certainly true that according to our common understanding, brains in vats do not have hands. So there is a tension here: the argument that it would be true to say we have hands even in that situation seems like a good argument, but so does the argument that it would be false that we have hands.

The answer to the difficulty is that we need to consider the meaning of “I am a brain in a vat.” Just as the word “hands” should refer to these two things in front of me, whatever they are, so the word “brain” refers to things inside of people’s heads, whatever they are, and the word “vat” refers to other things we sometimes experience in real life, at occasionally, or something very like them. But this means that just as “I have two hands” is to be understood in whatever way is needed to make it true, so also “I am not a brain in a vat,” is understood in whatever way is needed to make it true.

This means that correct answer to the original question was simply, “No, it isn’t possible that I will turn out to be a brain in a vat, regardless of any later discoveries, and it isn’t possible that the sun will turn out not to rise, regardless of discoveries about the motion of the sun and of the earth.”

The skeptic will want to insist. Surely events like those of The Matrix are at least conceivable. And if some such situation turned out to be true, then wasn’t it true that you were in a skeptical scenario and that your beliefs about hands and brains and vats were all false, and especially would it not be the case that your belief that you weren’t in a situation like that was false?

The correct answer, again, is that your original beliefs were not false. But in view of your new knowledge of the world, you might well want to adopt a new mode of speaking, and say things that would sound opposed to your original beliefs. They would not be opposed, however, but would simply be speaking about things you did not originally speak about.

Note however that “your belief that you weren’t in a situation like that” could now be taken in two ways. It could mean my belief that I am not a brain in a vat, and this belief will never turn out to have been false. Or it could mean a belief that there is not some larger view of reality where “he was a brain in a vat” would be a reasonable description, in the way that someone coming out of the Matrix would acquire a larger view. In reality I have the latter belief as well, as I consider it improbable that any intelligent beings would behave in such a way as to make that scenario probable. But I don’t think it is impossible for this belief to be falsified; and if it were, I would not say that my previous common sense beliefs had been false. This corresponds to what Pruss says at the end of his post, where he says that as long as things have forms, it is not really a skeptical scenario, even if in some sense he is in a computer simulation or whatever.

Why the insistence on form? This is related to what we called the Semi-Parmenidean Heresy. There we discussed Sean Carroll’s view, and noted that his position in essence is this: Metaphysically, the eliminativists are right. But it is useful to talk as though they are wrong, so we’re going to talk as though they are wrong, and even say they are wrong, by saying that common sense things are real.

This is ultimately incoherent: if the eliminativists are mistaken, they are mistaken in their metaphysics, since the position is just a certain metaphysical position.

It is not difficult to see the connection. According to a strict eliminativist, it would be literally true that we do not have hands, because there is no such thing as “we” or as “hands” in the first place. There are just fundamental particles. In other words, eliminativism would be even more of a skeptical scenario than the Matrix; the Matrix would not imply that your common sense beliefs are false, while eliminativism simply says that all of your beliefs are false, including your belief that you have beliefs.

And on the other hand, no scenario will be truly skeptical, even one like the Matrix, if it admits that our common sense beliefs are true. And as I said at the end of the post on Carroll’s view, this requires a metaphysics that allows those beliefs to be true, and this requires formal causes.

Alexander Pruss, however, seems to me to interpret this in a rather narrow way in his concluding remark:

If physical reality is the memory of a giant computer but it isn’t a mere simulation but is in fact informed by a multiplicity of substantial and accidental forms corresponding to people, trees, hands, hearts, etc., and these forms are real entities, then the scenario does not seem to me to be a sceptical scenario.

It is not clear what it means to be “real entities” rather than being unreal, given that you acknowledge them in the first place, and it isn’t clear to me what he means by a “mere simulation.” But this sounds a lot to me like, “If the world isn’t Aristotelian, understood in a very narrow way, then that would be a skeptical scenario.” This seems to me a kind of stubbornness much like that of James Larson. Disagreeing with you is not a war against being, and believing that your account of form and matter didn’t get every detail right, is not saying that our common sense beliefs are not true.

As an illustration of the narrowness in question, consider Pruss’s position on artifacts:

Suppose I am a plumber, and I take a section of pipe, insert a blowgun dart, and blow.  I just shot a dart out of a blowgun.  When did the pipe turn into a blowgun, though?

Did it happen when I formed the intention to use the pipe as a blowgun?  No: I do not have the power to make new material objects come into existence just by thinking about it.

When I picked up the pipe?  There are at least there is contact.  But surely it’s not the right kind of contact.  It would be magic if I could make a new material object come into existence by just picking up a material object with a certain thought in mind.

When I inserted the dart?  Presumably, not any insertion will do, but one with a plan to blow.  For I could just be doing plumbing, using the outer diameter of the dart to measure the inner diameter of the pipe, and that shouldn’t turn the pipe into a dart.  Again, we have some magic here–thinking about the pipe in one way while inserting the dart creates a blowgun while thinking about it another way leaves it a boring pipe.  Moreover, putting the dart into the pipe seems to be an instance of loading a blowgun rather than making a blowgun.

The solution to all this is to deny that there are pipes and blowguns.  There is just matter (or fields) arranged pipewise and blowgunwise.  And for convenience we adopt ways of speaking that make it sound like such objects are among the furniture of the universe.

Pruss is not simply putting out a position for discussion; this is what he believes to be true, as is easily confirmed elsewhere on his blog. Note that he is falling into the Semi-Parmenidean heresy here, except that he is even going farther than Carroll, and suggesting that “there are no pipes and blowguns” is a true statement, which Carroll would rightly deny. In this way Pruss is almost a pure eliminativist about artifacts. (He does also speak elsewhere more in the manner of Sean Carroll about them.)

To the degree that he is eliminativist about artifacts, he contradicts common sense in the same kind of way that someone contradicts common sense who says, “You do not have hands.” He just contradicts it about different things. And why about these things, and not others? I suggest that it is because under the ordinary Aristotelian account, it is likely that a man or a horse has a substantial form, but unlikely that a pipe has one. And although a pipe would have various accidental forms, the idea of a unified form of “pipeness” seems pretty unlikely. If this is actually his reason or part of it, then he is identifying skepticism with disagreeing with his philosophical opinions, even though his own opinions actually contain the skepticism: namely, disagreement with common sense.

My own response to this question would be different: being is said in many ways, and consequently also form and unity. And I reject any disagreement with common sense: men and horses are real, but so also are pipes. If I am not mistaken, all of these will have being and form in the way that is appropriate to them.

Composing Elements

Suppose we have two elements, as for example water and earth (not that these are really elements.) How do we make something out of the elements? We can consider two different possible ways that this could happen.

Suppose that when we combine one part water and one part earth, we get mud, and when we combine one part water and two parts earth, we get clay. Thus clay and mud are two different composite bodies that can be made from our elements.

How do we expect clay and mud to behave? We saw earlier that the nature of the physical world more or less requires the existence of mathematical laws of nature. Now we could say, “Clay and mud are made of earth and water, and we know the laws governing earth and water. So we can figure out the behavior of clay and mud using the laws governing earth and water.”

But we could also say, “Although clay and mud are made of earth and water, they are also something new. Consequently we can work out the laws governing them by experience, but we cannot expect to work them out just from the laws governing earth and water.”

These two claims are basically opposed to one another, and we should not expect that both would be true, at least in any particular instance. It might be that one is true in some cases and the other is true in some cases, or it might be that one side is always true. But in any case one will be true and not the other, in each particular situation.

Someone might argue that the first claim must be always true in principle. If water behaves one way by itself, and another way when it is combined with earth, then you haven’t sufficiently specified the behavior of water without including how it behaves when it is beside earth, or mixed with earth, or combined in whatever way. So once you have completely specified the behavior of water, you have specified how it behaves when combined with other things.

But this way of thinking is artificial. If water follows an inverse square law of gravity by itself, but an entirely different mathematical law when it is combined with earth, rather than saying that the entirely different law is a special case governing water, we should just admit that the different law is a law governing clay and mud, but not water. On the other hand, it is not unreasonable to include various potential interactions in your laws governing water, rather than only considering how water behaves in perfect isolation. Thus for example one would want to say that water suffers gravitational effects from all other bodies, rather than simply saying that water attracts itself. Nonetheless, even if the distinction is somewhat rough, there is a meaningful distinction between situations where the laws governing the elements also govern the composites, and situations where we need new laws for the composites.

In one way, the second claim is always true. It is always the case that something is true of the composite which is not true of the elements in themselves, since the composite is a whole composed of elements, while the elements in themselves are not. This is true even in artificial compositions; the parts of a bicycle are not a bicycle, but the whole is. And I can ride a bicycle, but  I cannot ride the individual pieces of metal that form it. Likewise, it is evidently true of living things, which are alive, and in some cases have conscious experience, even though the individual elements do not.

In a second way, the second claim is almost always true. If we consider our laws as practical methods for predicting the behavior of a physical system, in practice we will almost always need special laws to predict the behavior of a complex composite, if only because it would be too complex and time consuming to predict the behavior of the composite using laws governing only the parts. Thus people who wish to predict the weather use generalizations based on the experience of weather, rather than trying to predict the weather simply by considering more general laws of physics, despite believing that the weather is in fact a consequence of such general laws.

In a third way, the first claim is true at least frequently, and possibly always. If we consider the behavior of a bicycle or a computer, not with respect to general questions such as “can I ride it?” or “can it calculate the square root of two?”, but with respect to the physical movement of the parts, there are good reasons to think that the behavior of the whole can be determined from the behavior of the parts of which it is composed. For these are human inventions, and although experience is involved in such inventions, people make guesses about new behavior largely from their understanding of how the parts behave which they plan to put together. So if the whole behaved in ways which are significantly unpredictable from the behavior of the parts, we would not expect such inventions to work. Likewise, as said above, there is little reason to doubt that the weather results from general principles of physics that apply to earth, air, water, and so on.

I say “possibly always” above, because there is no case where the second claim is known to be true in this sense, and many instances, as noted, where the first is known or reasonably believed to be the case. Additionally, one can give reasons in principle for expecting the first claim to be true in this way, although this is a matter for later consideration.

An important objection to this possibility is that the fact that the second claim is always true in the first way mentioned above, seems to imply that the first claim cannot be true even in the third way, at least in some cases. In particular, the conscious behavior of living things, and especially human free will, might seem inconsistent with the idea that the physical behavior of living things is in principle predictable from laws governing their elements.