The Identity Theory in 2-D

I plan on writing a series of posts discussing various themes that came up in discussion at the online consciousness conference.

I have long been a type-type identity theorist. There was a time when I thought that I would write my dissertation defending a version of identity theory (in fact the very first talk I gave at a professional meeting was what I thought of as a ‘pre-prospectus’ available here: Saying “I Do” to Identity. I presented this as a poster at the ASSC in Antwerp and as a talk at the SPP in Barcelona (I called this my “European Identity Tour”))…When I approached Michael Devitt about the idea he said that people used to be interested in the identity theory but that people had moved on…it turns out that people are getting re-interested in the identity theory in the wake of work by people like Tom Polger, Chris Hill, and Ned Block. One thing that came out very clearly in the discussion is the difference between the identity theory that Block holds from the kind that I hold. The main difference concerns how we will eventually come to discover the mind-brain identities. Broadly speaking there are two different camps.

It is useful to remind ourselves of what the originators of the identity theory held. In “Is Consciousness a Brain Process?” U. T. Place says,

The answer seems to be that we treat the two sets of observations as observations of the same event in those cases where the technical scientific observations set in the context of the appropriate body of scientific theory provide an explanation of the observation of the man in the street. Thus we conclude that lightning is nothing more than a motion of electric charges, because we know that a motion of electric charges through the atmosphere, such as occurs when lightning is reported, gives rise to the visual stimulation which would lead an observer to report a flash of lightning (p. 58 in Chalmers 2002)

J.J.C. Smart in “sensations and Brain Processes” writes,

Why do I wish to resist [the suggestion that qualia are irreducibly psychial]? Mainly because fo Occam’s razor. It seems to me that science is increasingly giving us a viewpoint whereby organisms are able to be seen as psyico-chemical mecanisms: it seems that even the behavior of man himself will one day be explicable in mechanistic terms…That everything should be explicable in terms of physics (together of course with the descriptions of the ways in which the parts are put together –roughly, biology is to physics as radio-engineering is to electro-magnetism) except the occurrence of sensations seems to me to be frankly unbelievable. Such sensations would be “nomological danglers,” to use Feigl’s expression

We can see here an emphasis on the notions of explanation and parsimony. 16 years later David Lewis and David Armstrong establish the alternative camp. Lewis puts it most clearly when he writes,

Psychophysical identity theorists often say that the identifications they anticipate between mental and neural states are essentially like various uncontroversial theoretical identifications: the identification of water with H2O, of light with electromagnetic radiation, and so on. Such theoretical identifications are usually described as pieces of voluntary theorizing as follows. Theoretical advances make it possible to simplfy total science by positing brdge laws identifying some of the entities discussed in one theory with entities discussed in another theory. In the name of parsimony, we posit those bridge laws forthwith. Identifications are made, not found.

In ‘An Argument for teh Identity Theory,” I claimed that this was a bad picture of psychophysical identification, since a suitable physiological theory could imply psychophysical identites –not merely make it reasonable to posit them for the sake of parsimony. The implication was as follows:

Mental state M=the occupant of causal role R (definition of M)
Neural state N=the occupant of causal role R (by the physiological theory)
Therefore Mental state M=neural state N (by transitivity of =)

Nor is this peculiar to psychophysical identifications. He goes on,

…the usual account is, I claim, wrong; theoretical identifications in general are implied by the theories that make them possible –not posited independantly. This follows from a general hypothesis about the meaning of theoretical terms: that they are definable functionally, by reference to causal roles (Psychophysical and Theoretical Identifications)

In a recent paper on functional reduction Ned Block targets the Lewisian view in favor of the Place/Smart view. Here is what he says,

If we want to know why water = H2O, freezing = molecular lattice formation, heat = molecular kinetic energy, temperature = mean molecular kinetic energy, etc, we have to start with the fact that water, temperature, heat, freezing and other magnitudes form a family of causally inter-related “macro” properties. This macro family is mirrored by a family of “micro” properties: H2O, mean molecular kinetic energy, molecular kinetic energy and formation of a lattice of H2O molecules. (Of course a given level can be micro with respect to one level, macro with respect to another.) The key fact is that the causal and explanatory relations among the macro properties can be explained if we suppose that the following relations hold between the families: that water = H2O, temperature = mean molecular kinetic energy, heat = molecular kinetic energy and freezing = lattice formation. For example, why does decreasing the temperature of water cause it to freeze? Why does ice float on water? Here is a sketch of the explanation: The oxygen atom in the H2O molecule has two pairs of unmated electrons, which attract the hydrogen atoms on other H2O molecules. When the kinetic energy of the molecules decreases, (i.e. the temperature decreases) each oxygen atom tends to attract two hydrogen atoms on the ends of two other H2O molecules. When this process is complete, the result is a lattice in which each oxygen atom is attached to four hydrogen atoms.Ice is this lattice and freezing is the formation of such a lattice, which is why decreasing temperature causes water to freeze. Because of the geometry of the bonds, the lattice has an open, less dense structure than amorphously structured H2O (viz., liquid water)–which is why ice (frozen water) floats on liquid water.

Suppose we reject the assumption that temperature is identical to mean molecular kinetic energy in favor of the assumption that temperature is merely correlated with mean molecular kinetic energy? And suppose we reject the claim that freezing is lattice-formation in favor of a correlation thesis. And likewise for water/H2O. Then we would have an explanation for how something that is correlated with decreasing temperature causes something that is correlated with frozen water to float on something correlated with liquid water, which is not all that we want. The reason to think that the identities are true is that assuming them gives us explanations that we would not otherwise have and does not deprive us of explanations that we already have or raise explanatory puzzles that would not otherwise arise. The idea is not that our reason for thinking these identities are true is that it would be convenient if they were true. Rather, it is that assuming that they are true yields the most explanatory overall picture. In other words, the epistemology of theoretical identity is just a special case of inference to the best explanation. (See Block, 1978a; Block, 2002; Block & Stalnaker,1999).

Block goes on to argue that the Lewis style view is incompatible with the metaphysics of physicalism. Block distinguishes between ontology and metaphysics. Ontological physicalism is just the claim that in our ontological commitment to the existence of qualia we commit ourselves only to physical entities (ontological dualists deny this). Metaphysical physicalism is the claim that qualitative properties are essentially or metaphysically physical. That is to say that all qualitative properties will share the same physical properties in so far as they are physical. the Lewis style physicalism is ontologically but nit metaphysically physicalist. This is because as it happens all of the realizers of mental states are physical but metaphysically pain is a functional state for Lewis and only contingently a physical state. Metaphysical physicalism –real physicalism in Block’s view– says that it is not contingent but necessary that pain is a physical state.

But if we adopt the 2-D framework and put the Lewisian claims in terms of it this is no longer a problem. On this kind of view the functional definition gives us the primary intension of ‘pain’ and the physical state gives us the secondary intension. This allows us to treat ‘pain’ just as we do ‘water’. ‘Water is H2O’ has a contingent primary intension and a necessary secondary intension. So we can update Lewis view that ‘pain’ isn’t a rigid designator as the claim that the primary intension of pain is contingent (just like ‘water’). ‘Pain’ is still a rigid designator in the ordinary sense that its secondary intension is necessary. In all worlds considered as counter-factual pain is a brain state. However we accommodate the conceivability of Martians and disembodied minds by noting that in some worlds considered as actual pain is not a brain state (just as in some worlds considered as actual water is not H2O). This does not threaten the identity; it is the usual way that theoretical identities work. Notice also that this 2-D identity theory is a metaphysical physicalism in Block’s sense and not merely an ontological physicalism.

Of course the real resistance to the 2-D Lewisian identity theory is that qualitative states are not supposed to be functionally definable. In fact Block and Chalmers often talk as though qualitative properties are definable as ‘the not functionally definable properties of experience’ (more on that later). If that is your view then you cannot do the Lewsian deduction of the identity. What are we to make of this? I will come back to this in the next post.

The Matrix & Nonphysical Properties

(cross-posted at Brains)

I have long wondered what dualists mean when they speak of nonphysical properties. Today I was reading Chalmers’ paper The Matrix as Metaphysics and he says something that may shed some light on the way in which he thinks of nonphysical properties. He argues that the matrix scenario can be construed as a metaphysical hypothesis about the ultimate nature of the physical world. If this is right then there is a sense in which dualism is true. The mind is a distinct entity that exists outside of physical space-time and causal interacts with the physical body. This is because the physical theory that is true of reality in the matrix is a computational theory on which the ultimate things which exist are bits (zeros and ones). Thus brains in the matrix are ultimately composed of bits and when people in the matrix talk about brains they ultimately are talking about bits. The brain which is outside of the matrix is not composed of bits (let us assume). It is ultimately composed of something else (let’s say strings). Thus the brain outside the matrix, when viewed from the perspective of someone who is in the matrix, is nonphysical. It is not something that could be deduced from a completed matrix microphysics (which would be phrased in terms of ones and zeros).

One might wonder whether a completed matrix physics would have to be supplemented with (from the perspective of the matrix) nonphysical laws in order to capture outside the matrix facts or whether we might view the truly completed matrix physics as being expanded to include the outside the matrix physics. On this latter view the laws of matrix-physics would be a special subset of the laws of outside-physics. If this were true then the matrix-physics would not be complete until it was expanded to include outside-physics and physicalism could still be true. One might also wonder whether people in the matrix had largely true outside-physics beliefs since the matrix world is a deliberate simulation of outside-physics.

But even setting aside these issues there are strange results. Suppose that physicalism is true and that consciousness is a purely physical property of the brain. Let us also assume that this is true of a brain that is not in a matrix scenario. Call this scenario 1. Now imagine that a physical duplicate of this physicalist brain that has been in a matrix scenario since birth Call this scenario 2). Then physicalism is true in scenario 1 and dualism is true of scenario 2. But these brains are physically identical! Furthermore this shows that we could not resolve the dispute between the physicalist and the dualist until one was in a position to determine whether or not one is in a matrix scenario. Since Chalmers himself admits that he cannot a priori rule out that he is not in a matrix scenario he must also admit that he is not in a position to a priori tell if physicalism or dualism true. So, suppose that we are actually in a matrix scenario then conceiving of zombies is just conceiving of a computer simulation composed completely of NPCs (non-player characters). But this doesn’t show that physicalism is false, since physicalism is best construed as the claim that lines up with the first brain; since with this understanding of nonphysical physicalism turns out to be nothing but the hypothesis that we are not in the matrix.

But even if we were in the matrix there is a sense in which we can say that physicalism is still ultimately true since in the above envisioned world qualitative properties turn out to be identical to properties which are physical in terms of outside-physics (since these properties are the very same as the ones in the world where physicalism is true).

Zoombies are creatures that are nonphysically identical to me in every respect and which lack nonphysical qualitative properties. I have in the past suggested that one way to conceive of zoombies is as Cartesian minds that only have thoughts but no qualia but now we can put it in terms of matrix scenarios. A zoombie has all of the same nonphysical properties that I in fact do. Suppose that I am in fact in scenario 2 above. Then a creature that has all of the nonphysical properties that I in fact do will have a brain that is identical to my outside-brain. This is to imagine scenario 1.

The traditional zombie is a creature that is physically identical to me and lacks consciousness. Now suppose that I have a zombie twin who is in a matrix scenario since birth. My matrix zombie twin has nonphysical properties (which are the very same properties that I physically have) but no qualitative properties. So, whether one has nonphysical properties or not is simply a matter of whether one is in the matrix or not. Chalmers’ defense of nonphysicalism can thus be seen as a defense of the claim that we are in the matrix.

Kripke on the Structure of Possible Worlds

Yesterday I attended Saul Kripke’s talk at the Graduate Center (there are quite a few interesting talk coming up…also looking good are the cogsci talks). The title of the talk was “The Structure of Possible Worlds: a Preface to a statement” and was subtitled, “Prolegomena to a talk on possible worlds, some considerations” so maybe I didn’t really attend a talk. Much of the talk, um preface to a prolegomena to a talk, consisted of Kripke going over the history of his thinking on modality, punctuated with his usual wit and humor. My two favorite moments were (a) the one where, after talking for an hour (the scheduled length of the talk), he stops and says “I may have to go over because I haven’t come to the main point yet” and (b) the one where, while discussing modal realism, he says “what does God have to do to make a really existing merely possible world actual; give it a kiss?” Ah, that Kripke should have his own reality show…I bet it’d be really popular!

As to the content of the talk, or whatever, he seemed to be indicating that (he may have) changed his mind about how he conceives of possible worlds. Here is how he put it in the handout,

I used to think that a sufficient account of my view of what a possible world is might be given by something like a Russellian structured proposition describing it. Now i think that one cannot give an account of what a possible world is in and of itself, but only as part of the structure of all possible worlds, or at least that modal logic cannot rule this out. (Even if there is not a unique structure of all possible worlds, structures where the problem I have just described arise cannot be ruled out philosophically.)

A structured Russellian proposition is an abstract entity that has as its constituents the actual objects in the proposition. So, to modify the classic example, the proposition that Jennifer Aniston loves Brad Pitt has Jennifer Aniston (the actual person), Brad Pitt (the actual person), and the relation of loving as constituents and these constituents are ordered by the loving relation such that Jennifer loves Brad (which is a different ordering from Brad loving Jennifer). This is just a more refined way of putting the basic point of Naming and Necessity. When we ask if Al Gore could have won the election we are asking a question about the actual Al Gore. We are not talking about some distinct object which merely resembles Al Gore (or which merely has many of the same descriptions true of it). There is therefore no issue of how we re-identify Al Gore in various possible worlds; it is the actual Al Gore.

So why does he now think that we can’t do this? (Of course, he hasn’t really come to this conclusion officially. What he said was that it might be true and he sort of leaned towards thinking that it is true). The basic reasoning he employed relies on his argument that there can be objects which are indistinguishable in every way which are none the less distinct. There is no criterion of identity that distinguishes these objects; as Kripke put it “the only difference between them is that there is a difference.” His favorite example is the square root of -1, known as i. i is equal to whatever number equals -1 when multiplied by itself. This number is not on the real number line and so is known as an imaginary number. The problem comes when we realize that i and -i are distinct numbers and that everything that is true of the one is also true of the other. i and -i are distinct yet have no clear criterion of identity.

The problem that Kripke sees is that something like this might be true for possible worlds. To see this he talks about what he calls ‘grounded’ objects. So, let’s imagine a world where there is an person, let’s call him George, who does not exist in the actual world. Let’s say that George is the son of two people who actually exist but do not actually have kids. In the actual world the sperm and egg that come together to form George never meet, but they do in some possible world. So George is grounded in the actual gametes that he could be the product of. But there is also the possibility of ungrounded objects. So consider Georgette. Georgette is a women who does not exist in the actual world but does at some possible world, yet unlike George, Georgette is not the related to any past, present, or future actual person. The sperm and egg which come together to form Georgette at no time exist in the actual world; they are the products of an alternate history which does not overlap with the actual world (in this respect). Georgette is ungrounded.

So if there can be ungrounded entities then we can see that the following situation is possible. Imagine that there are two possible worlds each which has an extra hydrogen atom which is not related to anything that actually exists. These two extra hydrogen atoms are thus ungrounded. We can furthermore imagine that these two hydrogen atoms are indistinguishable from each other. Now if this is the case then the two possible worlds we are imagining are indistinguishable yet distinct. There is nothing that we could say about the possible world in and of itself that could distinguish between these two worlds. The only way that we could distinguish them is by noting their relative positions to each other in the overall space of possible worlds. Thus Kripke concludes that we cannot talk about individual possible worlds except in relation to the entire structure of modality, or to be more modest, he concludes that there is no a priori consideration that would rule this kind of automorphism out.

An interesting argument, and there is a lot more to say about it but I will come back to that later.

The Problem with 2-Dimensional Semantics

Central to the claim of Chalmers’ two dimensional semantics is the idea that there are two different ways of considering a possible world. We may consider it counter-factually in which case we hold the actual world fixed or we may consider as actual in which case the proposed possible world is thought of as being actual, with our world then a counter-factual world. Thus Twin Earth, considered as actual, is a world where water is not H20 but is rather XYZ. From their point of view it is a necessary truth that water=XYZ and so there would be no water here on Earth (considered counter-factually).

The problem with this line is that it assumes that we can tell a priori which possible worlds there are. Before we can consider a possible world as actual, we need to know whether it is possible or not. The two-dimensionalist simply asserts that some world is conceivable and then proposes to consider it as actual. But we have no non-question begging way of saying what is or is not really conceivable. Some claim that to be conceivable is simply to lack any contradiction in teh thing conceived. But just because there is no obvious contradiction in a proposed conceivable world does not mean that there is no contradiction in that coneption. Besides whihc, there are those who claim that contradictions are conceivable. Kripke famously proposed ‘non-normal’ worlds (sometimes called ‘impossible worlds’) these are worlds where contradiction are true or where standard laws of logic fail to apply (like the rule of necessitation). Are such worlds conceivable? Kripke seems to think so, others do not.

Until we resolve this issue two-dimensional semantics is hopelessly question begging. The only thing that we can consider as actual is, well, the actual world.

Kripke’s Argument Against 4-Dimensionalism

In celebration of my one year in the blogosphere I have decided to start a new (randomly published) series of posts highlighting a post from exactly one year ago that did not recieve much attention. Here is the third  installment.


As I sit here and type this in late 2007, in my living room, it seems to me that all of me is in the room that I am in right now. From a common sense perspective I am entirely in this room; we can put this by saying that I am wholly present in this room. The four-dimensionalist denies this common sense claim. They think that I have some parts, temporal parts, which are not in this room right now. For instance, I have a temporal part that is at work yesterday, or is my child-hood self back in Los Angeles. This is a very odd view indeed! 4-dimensionalism is closely related to eternalism, which Jason has recently defended in an audio post over at Philosophical Pontifications. Kripke has a well known argument which is supposed to show that four-dimensionalism is false. It is a very simple argument which claims that the four-dimensionalist cannot capture certain basic facts about the world. In particular it is not able to capture certain facts about whether a certain disk was spinning in its lifetime or not. Let us look at his very simply argument.

Kripke has argued (in unpublished lectures) that the, as he calls it, Holographic Theory (so-called because the temporal slices are presumed to be three-D, like holograms) has serious problems by suggesting that it is unable to model certain facts about the history of the world. His argument relies on two thought experiments. First, consider a disk made from uniform material. It is a single color and is made from entirely continuous matter. Now, a disk modeled in three dimensions (which turns into a cylinder as it ‘progresses’ through the third dimension) is akin to modeling a three dimensional object in time. Any problems that our three-D model of the disk will have will be simplified versions of problems for the view that objects are four-dimensional. So, now what if we are looking at the resulting cylinder, which represents the disk’s ‘life’, and we wonder ‘was the disk spinning during its life?’ 

The temporal stage theory is unable to answer this question. We cannot answer the question because the model of the disk’s ‘life’ is incapable of representing this kind of fact. What we need in order to answer the question is an answer to the question ‘is some specific part of the disk now in another place?’ The same thing being at a different place later is what motion is. Since we have no criterion to determine if we have the same substance in the same place we cannot, in principle, answer the question about the disk’s motion. Presumably the disk was either spinning or not and since there is no way to account for this, one way or the other, the temporal slice theory is in trouble. The second thought experiment is quite similar and involves an infinite river. He introduces this variation only so that he may avoid the objection that a disk made from uniform matter is impossible. The water in the river takes care of this. We need not rehearse it here, as it is basically a reiteration of the previous argument applied to the river.  Kripke concludes that the temporal slice theory is wrong and suggests we that need a primitive notion of the identity of substance.

This really should not come as much of a surprise as it is clear that Kripke had this idea in mind when he delivered the lectures now known as Naming and Necessity. He argues that we can stipulate that we are talking about certain substances and ask what would happen to them in a possible world. This is only possible because there are substances out there with which we have interacted. It is because I have interacted with Kripke that I can ask what would happen to him, Saul Kripke, had he not been interested in philosophy. Similarly I can stipulate that I am talking about this table right here and ask about what happened to it yesterday, or what might happen to it three days from now. The argument that Kripke advanced against 4-d-ism is merely making explicit something that has been implicitly accepted by anyone who finds Kripke’s arguments compelling; Namely that we must take the logical relation of the identity of substance (A=A) as a primitive notion.

To illustrate Kripke talks about possible states of two six-sided die. The fundamental question is what we are to say in the cases where we get a four and a three, say. Is there just one state or are there two? Kripke argues that each possible state of the dice is distinct. These states will be distinct because the two die are enduring substances that we can rigidly designate. So each die will have a unique state that it can be in or not. Let us call the two die Alice and George. Then there is one possible state where Alice is four and George is three and another possible state where George is four and Alice is three. These two states are distinct even though the two dice, and so the two states, are qualitatively identical. Kripke’s basic admonishment is that we cannot count possible states of an object simply by qualitative similarity, as that collapse the number of possibilities.

In the next post I want to address Ted Sider’s temporal counter-part theory as a response to Kripke’s argument.

My Body has a Limp

Over at TAR Brian Weatherson offers an argument for thinking that the mind and body are not identical. He begins by discussing Ryle’s example of a limp and ask us to consider two sentences

5. I have a limp

6. My body has a limp

He suggests that 5 is true but 6 is false and that it is a kind of category mistake. This suggests that I am not my body (since I seem to have properties that my body doesn’t). He then goes on to say that this provides evidence for his favored view that people are events and so natually couldn’t be bodies.

The problem with this line of reasoning is that 6 will be true or false depending on whether 7 is true or false.

7. I am my body

If 7 is true then 6 will be true if 5 is. If 7 is false then 6 will be false independently of whether 5 is or not. Weatherson’s 6 is defective in the way that 8 is

8. Superman wears glasses

It sounds weird but we will ultimately admit that it is true because we accept ‘superman is Clark Kent’ and 8 follows from that and ‘Clark Kent wears glasses’. So his intuition that 6 is defective isn’t evidence that the mind and body are distinct; it is evidence that Weatherson thinks that they are.

The Terminator and Philosophy: Call for Abstracts

The Terminator and Philosophy

Edited by Richard Brown and Kevin S. Decker

The Blackwell Philosophy and Popular Culture Series

Please circulate and post widely.

Apologies for Cross-posting.

To propose ideas for future volumes in the Blackwell series please contact the Series Editor, William Irwin, at

Abstracts and subsequent essays should be philosophically substantial but accessible, written to engage the intelligent lay reader. Contributors of accepted essays will receive an honorarium.

Possible themes and topics might include, but are not limited to, the following:

“Can We Really Change the Future?” or “Killing Sarah Connor”: Cyberdyne Systems, time travel and the grandfather paradox; Skynet and John Connor: philosophy of technology and creating our own enemies; “Sentience, Sapience, and Self-Awareness”: issues in philosophy of mind; Neural Net to Supercomputer to ‘Software in Cyberspace’: Skynet and multiple realization;“Is Skynet Justified in Defending Itself?” the ethics of war and artificial intelligence; “Irrefutable Delusions”: Sarah Connor, Delusional Beliefs, and Standards of Evidence in T2;“Stop Miles Bennett Dyson”: Sarah Connor’s transformation into a killer (is violence contagious?) or Sarah Connor’s transformation from ‘80’s ditz to Feminist Icon; “Judgment Day is Unavoidable” or “No Fate but what we Make”: eternalist vs. presentist perspectives on the original versus modified timelines; “John Connor is the Most Important Person in the World”: causality and the meaning of life; “To Preserve and Protect”: the contrastive values of human versus artificial life; “What is a Terminator?”: The Ontology of Fictional Objects; “I Have Data Which Could be Interpreted as Pain”: machines, consciousness, and simulated perception; The T-1000: adaptable machines and emergence; How Did They Build Skynet?: “truthmakers” and knowledge with no source; Andy and the Turk: killing the innocent to save the innocent or Are scientists responsible for their inventions?; “Terminatrix”: the T3 gynoid , feminism, and trangressive cyborgs; “Should we Stop the Future?”: Conservatism and the “Terminator Argument” in bioethics; “The Closest Thing to a Father I Have”: John Connor & the Terminator; “Desire is Irrelevant, I am a MACHINE”: Who is Responsible for the Terminator’s Actions? Or freewill vs determinism; “Assume the Shape of Anything it Touches”: The Metaphysics of Transformation in T2 & T3; The Govinator: Fantasy and reality in politics; Does the Future Exist now?: The nature of spacetime and reality; Embodied Artificial Intelligence: Is AI actually possible, and if so, how close are we to creating it?; Monstrous Technology: From Frankenstein to the Terminator.

Submission Guidelines:

1. Submission deadline for abstracts (100-500 words) and CV(s): September 8, 2008.

2. Submission deadline for drafts of accepted papers: November 3, 2008.

Kindly submit by e-mail (with or without Word attachment) to: Richard Brown at

The Refutation of Rationalism

I am back from my vacation in Liberty City 🙂

Seriously though, gta 4 is a lot of fun and very addictive!

I have recently been very interested in showing that rationalism is hopeless. To be open, I confess that I used to be a rationalist when I was younger. When I first started studying philosophy I was very influenced by Descartes and found his talk of clear and distinct ideas and ‘the light of nature’ very compelling. There is no suprise here, as rationalism has been the dominant view in the Western tradition since its inception. But, as rationalists like Bonjour admit, rationalism has suffered several notorious and embarrassing setbacks. Perhaps the first of which goes back to Gallileo showing empirically that Aristotle’s physics was wrong in assuming that heaverier bodies fall faster than lighter bodies. More dramtically, perhaps, is the discovery of non-Euclidean geometry which showed that various of the fundamental postulates of geometry were not necessary (like the parralel postulate). We should perhaps add to this the discovery of Russell’s paradox and the various self-referential semantic/syntactic problems (i.e. Godel, the liar, etc) which have led to the development of alternative logics.

What this shows is that intellectual seemings are fallible. It cannot therefore be argued that something seeming to need no empirical support and seeming to be justified purely by reason is enough to establish that the fact in question is really justified independently of experience or not. So, take 1+1=2. It certainly seems that this is true, in fact it is hard for me to imagine how it could be otherwise. There is a strong subjective sense of certainty that I experience when I think about it. All of this is no doubt true. But we have as of yet no reason to think that it is REALLY necessary, or that its justification is independant of experience. This is because we can not tell a priori whether the intelectual seeming is indeed correct. This shows that rationalism is in serious trouble. There is no other reason to take rationalism seriously other than the strong pull these rational insights have on us.

One might want to reply by saying that is overly skeptical. We shouldn’t abandon a priori knowledge just because we have mistakenly identified somethings as necessary which weren’t. So too, the objector goes on, just because we hallucinate doesn’t mean that we don’t normally see objects. Fair enough. But then what we need is an actual account to back this up. What is the difference between the cases? We can give that in the empirical case. We can describe ways in which we could find out whether the person was hallucinating or not based on our ability to monitor the brain of the animal in question and our visual impressions of the experimental set up. We can give a sketch, if not every detail, of a story which desribes how the brain interacts with the enviornment it finds itself in and generates representations of that environment. But can you do the same for rationalism? To date no one has. What is an eternal, necessary, non-physical/non-natural object like a number or modus ponens really like? How do we interact with it? No one knows. How could they?

Now this would be a pressing concern if it were impossible for us to fully understand the world we live in except for the truth of rationalism. But this certainly isn’t the case. We have good candidates for materialistic accounts of every disputed area. For instance, in the area I know most about, we have the mind-brain identity theory and the higher-order theory of consciousness. I do not mean to say that we know that they are true, but only that they are viable candidates. For all we know right know they could be true. They have not been absolutely refuted by any a priori arguments, nor have they shown themselves to be inconsistent with the findings of science, quite the converse actually. As for math and logic we have either constructivism or Mill’s view that they are empirical generalizations (I interpret this to mean that they are an attempt to model the way that the physical world works and to grow into Quine’s indispensibility argument that the justification for mathematic is empirical), or a more modern version of deflationism or fictionalism about this stuff. The same is true for ethics.

Again, none of these has been demonstrated to be correct. The point, rather, is that we should prefer natuaristic/materialistic accounts ove their non-natural/non-physical competitors. They automatically become more plausible because of their reliance on the more plausible empiricist/scientific account of knowing.

Einstein and the a Priori

Tanasije has recently offered up Einstein as an example of how empirical science is dependent on a priori knowledge. His point seems to be that once Einstein had his two fundamental principles (i.e. the principle of relativity and the principle of the constancy of the speed of light) he was able to use ‘pure reason’ and deduce a priori the rest of his physics. But the question of a priori knowledge, I think, is the question of the status of the first principles and the status of the rules that we use to deduce the rest of the physics. It is only if you think that the two principles + rules for deduction are known to be necessary facts about the nature of reality independently of experience and solely by reason.

The empiricist can account for what Einstein did; the two principles followed from empirically validated theories of the time (the principle of relativity is stated by Galileo and is a part of Newtonian physics as Einstein knew it and the constancy of light is predicted by Maxwell’s equations). The rules that are used to deduce (i.e. classical logic) are highly useful empirical generalizations. So Einstein does indeed start from first principles and deduce physics (if that is indeed what happened), but nothing in the story told by the empiricist is really independent of experience.

In order to have some serious rationalism going on, one would have to add to Tanasije’s accoount the claim that Einstein’s principles and the rules of classical logic are known by reason to be necessary facts about reality. Einstein does seem to cite a thought experiment as evidence for the constancy of the speed of light. He says he imagines chasing after a beam of light. What would it look like? If Einstein could catch up with the beam and look at it how would see the light standing still, which is unintuitively odd. So, he must not actually be able to catch up to the beam. But the only way that that is possible is if its speed were constant relative to Einstein no matter how fast he went. QED.

But is this really evidence for rationalism? Not quite. Some scientists (Paul Davies, for instance) think that that the speed of light may have been slowing down since the Big Bang. What is going on here seems to be this. We have a theory wich is the one that best unites disperate phenomena and is empirically adequate. We usually have outlying data and often scientists take creative leaps to integrate these outlying data points and thereby unite more disperate phenomena and provide greater empirical adequacy. It is plausible to think that Einstein himself was motivated by a conflict between theories he found intuitively compelling for the reasons cited above.

The moral of the story? Intuitions are theory driven and not ‘tother way ’round!

Armstrong on Naturalism and Empiricism

I was reading the NPDR reviewof a recent book on the philosophy of David Armstrong. I found this review very interesting as I have been very influenced by David Armstrong myself (and have even had the privilege of auditing his course on truthmakers at the Graduate Center) though I can’t say I agree with all of his views. At anyrate, in light of all of the zombie stuff lately this got me to thinking.

Naturalismis a metaphysical thesis that claims that everything that exists does so entirely in one single space-time system. Both idealists and materialists/physicalists can be naturalists in this sense.  This is to be distinguished from empiricism which is the epistemological thesis that claims that the only way to acquire knowledge is the empirical a posterori way used by science. Armstrong’s main argument for naturalism relies on what he calls the  Eleatic principle. This principle says that we ought NOT to posit the existence of entities that have no causal powers. So, if empiricism is correct then the Eleatic principle offers strong support for naturalism and from naturalism to materialism/physicalism.

Why should we adopt empiricism? The best argument I have seen is Devitt’s abduction. He argues that when we have two competing theoretical explanations we should opt for the one that is better understood. I think there are other, related reasons for adopting empiricism. In the first case we have never had to appeal to non-natural entities in any succesful explanation. Each time we have appealed to some non-natural entity we have eventually discovered a plausible candidate for a natural explanation. I have also argued that if anything like evolution turns out to be true then we cannot appeal to intuition as evidence for rationalism (and against empiricism). This is because, given that the our experience of the world has been regular and uniform up until now, we would expect that there would be certain truths which seem to be self-evident but are really just the product of a long process of natural selection in response to a stable environment. If this were the case we would have the very same intuitions that the rationalist appeals to and so the rationalist must have another argument. But none that I know of have been given.

The Eleatic principle also is wielded as an argument from naturalism to materialism. If a non-material entity has no causal powers then according to empiricism we cannot know about it and so would never have any reason to posit its existence. If it does have causal efficacy then it is of a type that is completely mysterious and unlike anything that we have hitherto encountered. So materialism is itself an empirical hypothesis.

 So, if one were to ask ‘but why is it matter rather than something else?’ The answer would be ‘because we discovered that waht it is’. If one wanted more than this, and insisted on asking ‘but what is the reason that it was that way to be discovered?’ The answer would be that it happens to be the case that the actual world is one where there is causation and you need material for that.