Place's article avoids dealing with an explicit analysis of mental concepts, in part because Place's goal is to demonstrate the logical possibility of the identity theory, and the logical possibility doesn't seem to depend on a particular analysis of the concepts involved. But, in order to provide a substantive identity theory, more work needs to be done: namely, and understanding of the meaning of mental concepts. In other words: Place makes a good case that "consciousness is a brain process" could be on similar footing with "lightning is electric charges." But, it seems much easier to understand the meaning of "lightning" than it is to understand the meaning of "consciousness", or any other mental concept.
I love Armstrong's honesty in admitting that he's not quite sure what's going on in conceptual analysis. This topic is bound to come up again and again during our readings. Unfortunately, and unsurprisingly, Armstrong does not solve the problem of conceptual analysis here. However, I want to point out two interesting things going on in his discussion of conceptual analysis:
(1) The idea of conceptual analysis as a research program (a la Lakatos) seems like a refreshing way to think about the nature of, and possible progress in, philosophical analysis. I'm pretty sure that Lakatos' approach to scientific theories has only been applied to the study of theory development/change in the natural sciences, and not to the social sciences. So it's a pretty big jump to think of conceptual analysis in philosophy along these lines. Still...
(2) Is the conceptual analysis of poison actually similar to the conceptual analysis of mental concepts? I don't know. What would a conceptual analysis of lightning look like? What does Armstrong mean when he says "it is surely not an empirical fact, to be learnt by experience, that poisons kill."
Armstrong and the Problem of the Secondary Qualities: Part of this I think has to do with qualia issues that we'll get to in future readings. His first response looks similar to Place's discussion of the phenomenological fallacy. Then he moves on to the nature of secondary qualities such as color. I'm content to leave this issue alone for the time being.
Monday, April 30, 2007
PCRG Reading Schedule Update
We'll go in the following direction (of course, suggestions and requests are always welcome):
- Armstrong's Materialism (one paper in Mind & Cognition and one photocopied in the office): Introducing the Causal Theory of Mind (Early Functionalism)...
- Prinz & Goldman/Pust. (photocopies in office) We detour (only slightly) into methodology: a look at conceptual analysis. What kind of philosophical and scientific work might/should we expect from the modal intuitions generated by the method of cases? Do they provide a privileged sort of data? What should we expect from the philosophy of mind, if anything, over and above what the 'sciences' of the mind might discover?
- Comparing and contrasting metaphysical essentialism with psychological essentialism. (photocopies in office). Are there any consequences (for instance) for Kripke's account of identity and necessity if metaphysical essentialism is ill-founded? Kripke relies heavily on the method of cases and semantic intuitions.
- Philosophical and Psychological Behaviorism. (Ryle, Skinner, Chomsky, Place, Quine, etc.). The shift from Behaviorism to Cognitivism in psychology is one of the most marked in recent scientific history. In the wake of that shift, Behaviorism has often come to be ridiculed as an embarrisingly untenable position. This is certainly unfair; it took the development of radically new technology and Chomsky, possibly the most celebrated intellectual in recent history to usher in a new paradigm. We should look closer to see what was motivating behaviorists, and where and why it was perceived to go wrong. What's the difference between Philosophical and Psychological Behaviorism? How are they related? I suspect we'll be on this for a while, once we get here.
Passing Thought on Kripke
Danny pointed out to me that we might be pulled to side with Kripke on the intuition that we can imagine heat in a world without creatures to sense the heat; there could still be the motion of molecules in such a world. I think there's more to be said about the identification of fundamentlly sensory properties like heat, but I won't investigate here.
Crucially, the question is can we imagine pain in a world without creatures to sense pain? I'm not sure how much it matters how we answer this question. If we take pain to be a property of nervous systems, which are physical things in the world, isn't asking if we can imagine pain where there're no creatures to sense it just like asking whether or not we can imagine heat in a world with no molecules? If so, Kripke's intuitions might be misleading, or maybe even incoherent. More later, but I'd like to hear thoughts about this...
Crucially, the question is can we imagine pain in a world without creatures to sense pain? I'm not sure how much it matters how we answer this question. If we take pain to be a property of nervous systems, which are physical things in the world, isn't asking if we can imagine pain where there're no creatures to sense it just like asking whether or not we can imagine heat in a world with no molecules? If so, Kripke's intuitions might be misleading, or maybe even incoherent. More later, but I'd like to hear thoughts about this...
Saturday, April 28, 2007
This Pain and the Concept, PAIN
To try to clear up some suggestions (mostly for myself) I made last time, let's consider some identity statements, coupled with counterfactual statements:
(1) This table is made of wood.
(1*) This table might have been made of ice.
(2) This table is a packing case.
(2*) This table might have been a coffin.
(3) Cicero is Tully.
(3*) Cicero might not have been Tully.
(4) Heat is the motion of molecules.
(4*) Heat might not have been the motion of molecules
(5) Pain is a brain process.
(5*) Pain might not have been a brain process.
What distinctions might we draw here, and do they matter? The first thing that sticks out is that the 1-3 examples include either indexical reference or reference to particulars; 4-5 include general terms of reference. Also, the verification conditions for the 3 are ordinary, by which I mean they can be verified by the experience of the linguistically competent man on the street, given access to the particular referents. The latter 3 require sophisticated equipment, and maybe a lot of education to verify. I won't explore whether or not this matters here.
1-2 make reference to the composition of particulars, 3 includes only two names denoting a single object, 4-6 include reference to the composition properties. I'll try to unpack this below a little, because I think these distinctions are significant; they may affect which among these, if any, should be understood as necessary identities, such that it’s counterpart (*) is (metaphysically/logically?) impossible. I suggest that the case of the particular identities is importantly different from that of the general ones.
In 1-2 there is pull to the intuition that, once verified, the identities could not have been otherwise. When we go to the (*) counterpart sentences, it is not at all clear that were the table made of ice, or were the table a coffin put to another use, that we’d be talking about the same table in either (*) case. Maybe it is necessary that this table is made of wood, etc. ; there seems to be a straightforward sense in which indexicals rigidly designate.
With regard to 3, similar considerations apply. We may individuate reference for ‘Cicero’ and ‘Tully’ by different contingent facts functioning as descriptions about one and the same individual, but that we associate contingent facts with different names doesn’t imply that identity of the referents is contingent. Regardless of what descriptions apply, talk of Cicero and talk of Tully is talk of the same man. The (*) counterparts look impossible here, too; maybe proper names are good candidates for rigid designators, too.
The situation is less clear when we get to 4-5. We should look at them in turn. In 4, as was indicated, we refer to a property (not an object) and endorse its identity with a physical phenomenon. On the one side we have a property of a kind of subjective, apparently private, experience, the sensation of ‘heat’. On the other, the motion of molecules taken to be the same thing. As Kripke notes, we apparently use the contingent fact that ‘heat’ causes the sensation of ‘heat’, to identify ‘heat’. Crucially, there is supposed to be an analogy between contingent reference conditions for properties like ‘heat’ and contingent reference conditions for names like ‘Cicero’. We pick out Cicero by the contingent fact that he was a statesmen; so says Kripke, we pick out ‘heat’ by the contingent fact that it produces a particular kind of experience/sensation.
It is not clear at all to me that there is not some question begging going on here. If not, Kripke’s language is extremely confusing; he can’t mean to say we pick out ‘heat’ in the world by the contingent fact that it causes such and such a sensation. He must mean that we pick out the motion of molecules in the world by the fact that it produces such and such a sensation. But if that is right, and the sensation is only contingently related to the motion of molecules, then the identity is contingent. Kripke hasn’t shown that HEAT and MOTION OF MOLECULES are conceptually connected in such a way as to make the identity necessary. He would’ve had to show that there is something to the concept HEAT over and above the sensation. So, the (*) sentence does not express an impossible state of affairs in this case (4*), due to an important, if only implicit, disanalogy with cases of particular-object reference: we can imagine Cicero not being a statesmen, but we cannot imagine him not being Tully; but, unless HEAT is more than just a sensation correlated with a lot of molecular agitation, we can imagine that it is not identical with molecular motion.
What about the case of pain? In 5, we refer to a (less controversially, at least on the face of it) apparently private kind of state of consciousness, and endorse its identity with a neurological process. Kripke thinks this case is importantly different from (4): that is, we do not pick out states of pain by the contingent fact that we sense pain in a particular way. But here Kripke ignores the fact that we are no longer expressing an identity statement about a particular (and it may be that this owes to his target, strict identity, but his arguments against materialistic identity as a program appear to be defeasible); His crucial move seems to be this:
[it] 'might be true of the brain state [that we pick it out by the contingent fact that it affects us in a particular way], but it cannot be true of the pain. The experience itself has to be this experience, and I cannot say that it is a contingent property of the pain I now have that it is a pain.’
Fair enough, but that’s not what (5) says, and the material identity theorist doesn't need to be so strict. Even Place, in particular, might have been able to argue that Kripke conflates (5) with (7):
(7) This pain is a brain process.
(7*) This pain might not have been pain.
Now, consider:
(8) This heat is the motion of molecules.
(8*) This heat might not have been the motion of molecules.
Switching from general claims to specific claims does change the climate. But how so?
Presumably, PAIN should be read here as I indicated HEAT might be read above: there maybe nothing more to the experience of pain than the sensation or experience. Grant Kripke that this pain or that pain is necessarily pain; (7*) is impossible. But this does not imply that (5*), ‘Pain might not have been a brain process,’ is impossible. In other words, it may be necessary to claim that that 'this pain is this brain process,' but it need not be necessary that 'pain is a brain process': contra Kripke, ‘Pain is a brain process’ might really be a contingent identity statement, even though cases of particular pain might express necessary identity relations between particular experiences and whatever underwrites them.
Since we can imagine PAIN in creatures very unlike us (like Lewis’ Martian) we don’t need to identify PAIN as a kind with 'pain' as referring to this or that sensation/experience. I think the same goes for HEAT. This or that sensation of heat rigidly designates the experience as the reference, but it doesn’t rigidly designate HEAT as the motion of molecules. Since the identity is plausibly a contingent one, the materialist is not required to answer Kripke’s challenge that ‘he has to show that [pains without brain states] are impossible.’
Tuesday, April 24, 2007
Kripke in ‘Heat’
I want to pick up on some points that Danny was bringing up in his last post…
To pit the relevant points against each other, Kripke’s attack is on the claim that, ‘consciousness is a brain process’, is a contingent identity statement. For the ID theorist, I guess, this kind of identity is desirable because it allows for a the conceptual independence of relata that are ontologically identical. This way the layman can talk about lightning without knowing anything about electric discharge, heat without knowing anything about molecules, and pain without knowing anything about neuroscience. This seems to be Place's antidote to dualist arguments resting on an insistence of the ontological independence of reference for distinct concepts.
Now embark an experiment in thought with Kripke guiding. We should entertain the question along the way as to whether Kripke is begging the question against ID by assuming that conceptual distinctions belie ontological ones. I find the experiment unconvincing, and I’d like to hear some input about whether or not I’ve got it right and why it has had so much pull for folks.
Imagine a population of Martians who feel ‘heat’ when they touch ice, or any other solid with exceptionally slow molecular motion and feel ‘cold’ when they touch fire, and other objects where there’s lots of molecular agitation. I think we can imagine this situation. Given the conceptual distinction here, are we entitled to say that ‘heat is the motion of molecules’ is a true identity statement of sorts? The ID guys say yes, but it’s a contingent identity; Kripke says yes, but it’s a necessary identity: the conceptual distinction we think we see isn't really there.
On Kripke's account, we just first say, yes, it’s just that Martian ‘heat’ is cold and Martian ‘cold’ is heat. But, of course, we aren’t talking about terms here, not about what Martians would say in martianese or in what they would say in English if they new it, when having a particular kind of experience. We’re talking about sensations, and Kripke invites (implores?) us to join him in the intuition that, even were there no creatures to feel ‘heat’, heat would still be identical with the motion of molecules. But this is altogether less obvious. If anything, if we are wont to award some pull to Kripke’s imagination, he seems to be readable as giving an argument for the non-identity of reference for our concepts of HEAT and MOTION OF MOLECULES.
For instance, where there are no creatures to sense ‘heat’, one might also be pulled to say that, sure, there might exist the motion of molecules, but that needn’t be identical with ‘heat’ as we know it. This is plausible if we allow imaginary things like Martians who feel ‘cold’ where we feel ‘heat’. The sensations themselves, as Kripke points out, are contingent. But there is no argument here that the sensation of ‘heat’ is essential to the motion of molecules, in fact, just the opposite seems to be supported. If we disallow contingent identity, we might wonder whether we have an identity statement here at all. All things being equal, functionalism is looking more and more attractive. If we allow that the motion of molecules might produce a different sensation in an exotic kind of ‘nervous system’, why assume that ‘heat’ is identical to the motion of molecules just because we sense it that way?
But it is worth noting that Kripke completely side-steps what Place and Smart have in mind: that sensations of ‘heat’ might be brain processes. Leaving this as an empirical hypothesis, there is room to say that other kinds of brains (maybe Martian brains) might sense the motion of molecules as ‘cold’. But this is either just a defense of the contingent identity holding between the referents of ‘heat’ and ‘motion of molecules’, or it’s an argument for the non-identity of these relata. But Kripke advocates neither.
Nevertheless, Kripke continues along this questionable line, taking it as a given that heat and the motion of molecules are the same thing (and necessarily so). What if there were no creatures initially, then some evolve, like the Martians, that sense what we call ‘heat’ as cold? Again, here, Kripke explicitly assumes the objectivity of the property of being hot and it’s identification with the motion of molecules. ‘Would we say,’ he asks, ‘that heat has suddenly turned to cold?’ No, he says, instead we’d say that Martians didn’t feel ‘heat’ when we do. But this seems to beg the question and to fail to address the issue of the phenomenological fallacy. We might say, to be more careful, that the Martians feel the motion of molecules differently. This, to some extent incompatible with Kripke's intuition that HEAT is the MOTION OF MOLECULES.
The problem I suspect is an equivocation on the sensation of heat and a theoretical conception of HEAT. At all events, the situation is markedly less clear when we substitute the identical predicates, ‘agitation of molecules’ and ‘slowing down of molecular motion’ for heat and cold respectively. We should say, then, that the new creatures sense heat when molecules slow down and cold when they’re agitated, and then contingent identity is confirmed, unless we presuppose that heat just is the motion of molecules. But the support for this presumption was not strong.
In effect, there is an important sense in which Kripke and the classical ID theorist might be talking past each other: heat is not, and should not be identified with the motion of ‘external’ molecules. Rather, if I can pretend I’m an ID theorist, ‘heat’ is just a sensation, and so a property of the nervous system; do we have any independent evidence otherwise? As the thought experiment shows, maybe the sensation of ‘heat’ should just be identified with contingent brain processes. So it might be the motion of molecules, but not anywhere else but in a nervous system appropriately composed.
All this may just point to a categorical difference between ‘simple’ sensations like heat, pain, taste, etc. on the one hand and those which are annexed to concepts like LIGHTNING, or LIGHT, and even HEAT, in there theoretical senses, on the other. If we avoid the phenomenological fallacy, by saying that heat is no property of an experience (no property of the world outside nervous systems; which is not to say that it is a property of an experience in a phenomenal field), and that the visual experience of lightning is the same, etc., the question becomes whether we are miss identifying 'heat' with the motion of molecules in objects outside the nervous system. But I don't think this is a real worry; we're after contingent identity after all, and we can tell some story about how processes in the nervous system are causally correlated with the motion of molecules in objects, we get contingent identity, of sorts. Maybe, this is a little daunting, and I’m not sure where it leads; without a broader metaphysical realism it might appear to problematic, but this wouldn’t concern Place who explicitly advances a scientific hypothesis.
I’ll wind it up by saying that the analogy with mind-body identity is correspondingly weak here. With regard to Kripke’s argument, I don’t see an obvious reason why we can’t treat PAIN like HEAT, at least tentatively. Kripke says we pick out heat by the contingent fact that it affects us in a particular way, but isn’t this the case with pain as well? With 'heat we just have the further consideration of the correlation between neural states and molecular states in objects; with 'pain' we're concerned with neural states only; but neither need involve an irreducible phenomenological story. This is why I suggest that Kripke equivocates on two senses of ‘heat’. The sensation of heat could be contingently identical to brain processes and the motion of molecules in objects; the important thing is that that would not entail that our sensation of heat is not identical to molecular motion. We have ‘heat’ our sensation, which is contingently identical to the motion of molecules in nervous systems, and 'heat' independently understood as the external motion of molecules. Both are independently verifiable, but one is a property of molecules in external objects and one (according to Place) would be a property of a brain process. But we needn't defer immediately to the phenomenological fallacy. If the ID theorist is right, then the 'external' vs 'introspective' distinction is misguided (at least in some cases) to begin with. If so, contingent identity by composition is alive.
To pit the relevant points against each other, Kripke’s attack is on the claim that, ‘consciousness is a brain process’, is a contingent identity statement. For the ID theorist, I guess, this kind of identity is desirable because it allows for a the conceptual independence of relata that are ontologically identical. This way the layman can talk about lightning without knowing anything about electric discharge, heat without knowing anything about molecules, and pain without knowing anything about neuroscience. This seems to be Place's antidote to dualist arguments resting on an insistence of the ontological independence of reference for distinct concepts.
Now embark an experiment in thought with Kripke guiding. We should entertain the question along the way as to whether Kripke is begging the question against ID by assuming that conceptual distinctions belie ontological ones. I find the experiment unconvincing, and I’d like to hear some input about whether or not I’ve got it right and why it has had so much pull for folks.
Imagine a population of Martians who feel ‘heat’ when they touch ice, or any other solid with exceptionally slow molecular motion and feel ‘cold’ when they touch fire, and other objects where there’s lots of molecular agitation. I think we can imagine this situation. Given the conceptual distinction here, are we entitled to say that ‘heat is the motion of molecules’ is a true identity statement of sorts? The ID guys say yes, but it’s a contingent identity; Kripke says yes, but it’s a necessary identity: the conceptual distinction we think we see isn't really there.
On Kripke's account, we just first say, yes, it’s just that Martian ‘heat’ is cold and Martian ‘cold’ is heat. But, of course, we aren’t talking about terms here, not about what Martians would say in martianese or in what they would say in English if they new it, when having a particular kind of experience. We’re talking about sensations, and Kripke invites (implores?) us to join him in the intuition that, even were there no creatures to feel ‘heat’, heat would still be identical with the motion of molecules. But this is altogether less obvious. If anything, if we are wont to award some pull to Kripke’s imagination, he seems to be readable as giving an argument for the non-identity of reference for our concepts of HEAT and MOTION OF MOLECULES.
For instance, where there are no creatures to sense ‘heat’, one might also be pulled to say that, sure, there might exist the motion of molecules, but that needn’t be identical with ‘heat’ as we know it. This is plausible if we allow imaginary things like Martians who feel ‘cold’ where we feel ‘heat’. The sensations themselves, as Kripke points out, are contingent. But there is no argument here that the sensation of ‘heat’ is essential to the motion of molecules, in fact, just the opposite seems to be supported. If we disallow contingent identity, we might wonder whether we have an identity statement here at all. All things being equal, functionalism is looking more and more attractive. If we allow that the motion of molecules might produce a different sensation in an exotic kind of ‘nervous system’, why assume that ‘heat’ is identical to the motion of molecules just because we sense it that way?
But it is worth noting that Kripke completely side-steps what Place and Smart have in mind: that sensations of ‘heat’ might be brain processes. Leaving this as an empirical hypothesis, there is room to say that other kinds of brains (maybe Martian brains) might sense the motion of molecules as ‘cold’. But this is either just a defense of the contingent identity holding between the referents of ‘heat’ and ‘motion of molecules’, or it’s an argument for the non-identity of these relata. But Kripke advocates neither.
Nevertheless, Kripke continues along this questionable line, taking it as a given that heat and the motion of molecules are the same thing (and necessarily so). What if there were no creatures initially, then some evolve, like the Martians, that sense what we call ‘heat’ as cold? Again, here, Kripke explicitly assumes the objectivity of the property of being hot and it’s identification with the motion of molecules. ‘Would we say,’ he asks, ‘that heat has suddenly turned to cold?’ No, he says, instead we’d say that Martians didn’t feel ‘heat’ when we do. But this seems to beg the question and to fail to address the issue of the phenomenological fallacy. We might say, to be more careful, that the Martians feel the motion of molecules differently. This, to some extent incompatible with Kripke's intuition that HEAT is the MOTION OF MOLECULES.
The problem I suspect is an equivocation on the sensation of heat and a theoretical conception of HEAT. At all events, the situation is markedly less clear when we substitute the identical predicates, ‘agitation of molecules’ and ‘slowing down of molecular motion’ for heat and cold respectively. We should say, then, that the new creatures sense heat when molecules slow down and cold when they’re agitated, and then contingent identity is confirmed, unless we presuppose that heat just is the motion of molecules. But the support for this presumption was not strong.
In effect, there is an important sense in which Kripke and the classical ID theorist might be talking past each other: heat is not, and should not be identified with the motion of ‘external’ molecules. Rather, if I can pretend I’m an ID theorist, ‘heat’ is just a sensation, and so a property of the nervous system; do we have any independent evidence otherwise? As the thought experiment shows, maybe the sensation of ‘heat’ should just be identified with contingent brain processes. So it might be the motion of molecules, but not anywhere else but in a nervous system appropriately composed.
All this may just point to a categorical difference between ‘simple’ sensations like heat, pain, taste, etc. on the one hand and those which are annexed to concepts like LIGHTNING, or LIGHT, and even HEAT, in there theoretical senses, on the other. If we avoid the phenomenological fallacy, by saying that heat is no property of an experience (no property of the world outside nervous systems; which is not to say that it is a property of an experience in a phenomenal field), and that the visual experience of lightning is the same, etc., the question becomes whether we are miss identifying 'heat' with the motion of molecules in objects outside the nervous system. But I don't think this is a real worry; we're after contingent identity after all, and we can tell some story about how processes in the nervous system are causally correlated with the motion of molecules in objects, we get contingent identity, of sorts. Maybe, this is a little daunting, and I’m not sure where it leads; without a broader metaphysical realism it might appear to problematic, but this wouldn’t concern Place who explicitly advances a scientific hypothesis.
I’ll wind it up by saying that the analogy with mind-body identity is correspondingly weak here. With regard to Kripke’s argument, I don’t see an obvious reason why we can’t treat PAIN like HEAT, at least tentatively. Kripke says we pick out heat by the contingent fact that it affects us in a particular way, but isn’t this the case with pain as well? With 'heat we just have the further consideration of the correlation between neural states and molecular states in objects; with 'pain' we're concerned with neural states only; but neither need involve an irreducible phenomenological story. This is why I suggest that Kripke equivocates on two senses of ‘heat’. The sensation of heat could be contingently identical to brain processes and the motion of molecules in objects; the important thing is that that would not entail that our sensation of heat is not identical to molecular motion. We have ‘heat’ our sensation, which is contingently identical to the motion of molecules in nervous systems, and 'heat' independently understood as the external motion of molecules. Both are independently verifiable, but one is a property of molecules in external objects and one (according to Place) would be a property of a brain process. But we needn't defer immediately to the phenomenological fallacy. If the ID theorist is right, then the 'external' vs 'introspective' distinction is misguided (at least in some cases) to begin with. If so, contingent identity by composition is alive.
Monday, April 23, 2007
What do you mean we, Kripke?
I didn't see Mike's post on the identity stuff until now, so this isn't at all a response to it, it's just my take on the Kripke paper. Here's what I think is going on:
According to identity theorists (IT), pain is identical with a neural state of type x. Those who oppose IT argue that we can imagine pain existing without that neural state, and therefore it can't be the case that pain is identical with a neural state. The standard IT reply is that this possibility of pain existing without that neural state doesn't justify a conclusion that pain is not identical with a neural state. Rather, this possibility shows that the identity statement is contingent, rather than necessary, and this shouldn't worry us because this is just another contingent scientific identification, similar to the identification of heat with molecular motion.
According to Kripke, there is an important difference between the identification of pain with a neural state, and the identification of heat with molecular motion. True identity statements of the form 'x is y' have the following setup: We observe something by way of some sort of description. We then give a name to the object that matches that description, and that name 'x' rigidly designates the object. Now, here's the important thing: If the description that we use to pick out the object rigidly designated by 'x' is an essential property of the object, then, if it is true that 'x is y', 'y' must have that essential property as well.
Often what happens in the case of (what Kripke thinks are mistakenly labeled) contingent identity statements is that we pick out 'x' with a contingent property, pick out 'y' with a different contingent property, and then discover that 'x' and 'y' rigidly designate the same object. This is what happens in the case of the identification of heat with molecular motion: we pick out 'heat' with the contingent property of producing a certain sensation (Kripke argues that this is contingent because we can imagine the existence of heat without it being felt, so therefore the sensation of feeling heat must be a contingent, rather than essential, property of heat), and pick out 'molecular motion' with a different contingent property, and then discover that 'heat' and 'molecular motion' designate the same object.
However, according to Kripke, pain is different: "Although we can say that we pick out heat contingently by the contingent property that it affects us in such and such a way, we cannot similarly say that we pick out pain contingently by the fact that it affects us in such and such a way." That is, Kripke has the following intuition (to be fair, derived from a thought experiment): There is a crucial distinction between pain and heat. We are able to imagine the existence of heat without it being felt, so therefore the sensation of feeling heat must be a contingent, rather than essential, property of heat. We are unable to imagine the existence of pain without it being felt, so therefore the sensation of feeling pain must be an essential, rather than contingent, property of pain.
If Kripke's argument works, it seems to undermine the IT reply to the objection that points out that we can imagine pain existing without that neural state. Remember, the IT reply is that this is just another contingent scientific identification. But Kripke has argued that contingent scientific identifications are true identity statements insofar as it isn't the case that [we pick out the object designated by 'x' with an essential property of that object, yet we can imagine the object designated by 'y' lacking that property]. And in the case of pain, Kripke has argued, we pick out 'pain' with the essential property of feeling pain, yet we can imagine the neural state (say, C-fiber stimulation, although that's not what neuroscientists think anymore, right?) lacking that property.
When I first read this article, I was extremely frustrated by it. To some extent, I still am. But I think I'm understanding the argument a little better, and it's a pretty cool way to block the IT reply. My problem with the argument is that it relies on notions such as "essential" that I can't make sense of and weird modal intuitions. How do we determine whether a certain property is an essential property of a particular object, or whether it is a contingent property? Is it dependent on what we would call that object if it lacked that property? Who is the "we"?
According to identity theorists (IT), pain is identical with a neural state of type x. Those who oppose IT argue that we can imagine pain existing without that neural state, and therefore it can't be the case that pain is identical with a neural state. The standard IT reply is that this possibility of pain existing without that neural state doesn't justify a conclusion that pain is not identical with a neural state. Rather, this possibility shows that the identity statement is contingent, rather than necessary, and this shouldn't worry us because this is just another contingent scientific identification, similar to the identification of heat with molecular motion.
According to Kripke, there is an important difference between the identification of pain with a neural state, and the identification of heat with molecular motion. True identity statements of the form 'x is y' have the following setup: We observe something by way of some sort of description. We then give a name to the object that matches that description, and that name 'x' rigidly designates the object. Now, here's the important thing: If the description that we use to pick out the object rigidly designated by 'x' is an essential property of the object, then, if it is true that 'x is y', 'y' must have that essential property as well.
Often what happens in the case of (what Kripke thinks are mistakenly labeled) contingent identity statements is that we pick out 'x' with a contingent property, pick out 'y' with a different contingent property, and then discover that 'x' and 'y' rigidly designate the same object. This is what happens in the case of the identification of heat with molecular motion: we pick out 'heat' with the contingent property of producing a certain sensation (Kripke argues that this is contingent because we can imagine the existence of heat without it being felt, so therefore the sensation of feeling heat must be a contingent, rather than essential, property of heat), and pick out 'molecular motion' with a different contingent property, and then discover that 'heat' and 'molecular motion' designate the same object.
However, according to Kripke, pain is different: "Although we can say that we pick out heat contingently by the contingent property that it affects us in such and such a way, we cannot similarly say that we pick out pain contingently by the fact that it affects us in such and such a way." That is, Kripke has the following intuition (to be fair, derived from a thought experiment): There is a crucial distinction between pain and heat. We are able to imagine the existence of heat without it being felt, so therefore the sensation of feeling heat must be a contingent, rather than essential, property of heat. We are unable to imagine the existence of pain without it being felt, so therefore the sensation of feeling pain must be an essential, rather than contingent, property of pain.
If Kripke's argument works, it seems to undermine the IT reply to the objection that points out that we can imagine pain existing without that neural state. Remember, the IT reply is that this is just another contingent scientific identification. But Kripke has argued that contingent scientific identifications are true identity statements insofar as it isn't the case that [we pick out the object designated by 'x' with an essential property of that object, yet we can imagine the object designated by 'y' lacking that property]. And in the case of pain, Kripke has argued, we pick out 'pain' with the essential property of feeling pain, yet we can imagine the neural state (say, C-fiber stimulation, although that's not what neuroscientists think anymore, right?) lacking that property.
When I first read this article, I was extremely frustrated by it. To some extent, I still am. But I think I'm understanding the argument a little better, and it's a pretty cool way to block the IT reply. My problem with the argument is that it relies on notions such as "essential" that I can't make sense of and weird modal intuitions. How do we determine whether a certain property is an essential property of a particular object, or whether it is a contingent property? Is it dependent on what we would call that object if it lacked that property? Who is the "we"?
Sunday, April 22, 2007
Some Considerations Regarding Identity
To frame what the identity theory is up against and, and prime for the Kripke thing, I’ll look in a little more detail here at what it would be for any one thing to be identical to another. Here is a plausible and more or less typical account (let’s call it L-identity, because I like nicknames and I think it’s Leibniz’s) of what it is for two things to be identical (tip your 40 to Leibniz):
(x)(y)(x = y → (Fx iff Fy))
That is, take any thing x and anything y: x is y only if, for any property F, if x is F then y is F (and vice versa). In other words, finally, two things are identical if and only if they share all properties in common. For our purposes, L-identity dictates that:
Consciousness is a brain process only if, for any property F, if consciousness is/has property F then some brain process is/has property F (and vice versa).
This seems to be enough to support the claim that strict identity clearly fails on this widely accepted criterion for identity. The non-identity theorist needs only to point out that conscious states like pain, pleasure, joy, and sorrow apparently have properties that whatever brain process(es) are correlated with them do not. Presumably these would be the so-called phenomenal properties. Neuro-cellular events are not, in and of themselves, joyous or painful unless a subject is consciously experiencing the states.
Of course, whether or not types or tokens of such states always underwrite the qualitative states is not especially important, because correlation is no criterion for identity. Smoking is correlated with lung-cancer, but they aren’t the same thing. Even perfect correlation doesn’t necessarily implicate an identity relation or even a causal relation. The point generalizes to cases of perceptual states like visual representations; for instance, there are no black or hot pink neural states, though particular neural states presumably underwrite the experience of color. By all counts, strict material identity fails if L-identity is our criterion.
But L-identity is not what Place appears to be talking about, and the ‘is’ of composition seems like it has the potential to do a lot of work here: ‘lightning is the motion of electric charges’ is an identity statement, but one with merely contingently identical relata, both of which are incapable of being simulaneously apprehended by a subject. We might ask whether the two relata share all properties in common, as is necessary if we accept L-identity, but this would miss the point that some phenomena are apparently identical in a different sense, though they may have radically different descriptions and radically disparate verification conditions.
So, Place leans on the following: (1) that whether or not the application of LIGHTNING and MOTION OF ELECTRIC CHARGES are appropriate in a particular case is an empirical question, depending on independently verifiable objects, and (2) to doubt that identical objects can have different verification conditions is to fall victim to the Phenomenological Fallacy (PF) which I’ll repeat here:
When a subject s describes his ‘introspective’ observations of so-called qualitative states (i.e. his experience of looks, smells, sounds, feels, and other seemings), s describes literal properties of objects and events experienced in the ‘phenomenal field’.
He explains PF in the context of after-images in a phenomenal field, but we can generalize to the experience of lightning. The lightning case, too, seems to fail L-identity, but this only seems important if we place too much stock in the phenomenological ‘data’. It may be that the point here is just the relatively simple one that one and the same event/object can have different descriptions. Do the motion of electric charges and lightning share all properties in common? Not phenomenologically, but if it is a true identity statement by composition, then yes, they do; we just can't from the perspective of a single subject, verify the identity simultaneously. All this is of course consistent with the fact that a hallucination of a bolt of lightning, or a dreamt experience of lightning is not identical with some instance of electrical charges in motion, since it does not pick out something so composed. It’s just that we’re in a brain state similar to that which are in when we experience real lightning. But to make the inferential leap from the conceptual independence of LIGHTNING and MOTION OF ELECTRIC CHARGES, together with their phenomenological independence, to non-identity is a species of PF, and is not clearly warranted at all. Moreover, it appears to be a contingent fact that the relata are identical, and that Place was right to insist that the claim ‘Consciousness is a Brain Process’ is a scientific hypothesis on par with ‘Lightning is the Motion of Electric Charges’.
What we might try to do is to qualify L-identity with a supervenience clause or something, so as to accommodate the ‘is’ of composition. This'll be messy, but, take anything x and anything y:
x is y only if, for any property F, if x is F then y is F (and vice versa), and bona fide occurrences of x are perfectly correlated with y such that if F is a directly observable phenomenal property, then F supervenes on G (a predicate describing the composition of x).
It’s sloppy and I won’t even bother trying to formalize it. But you can see what I’m thinking, F might have multiple descriptions, each depending on the level of material composition one is addressing. As Place notes, an accurate description of composition should not be ruled out as a candidate for an identity statement just because different properties are involved. Of course, this is not super-satisfactory with regard to other intuitions about identity. We still might be wont to say, motivated by L-identity, that we need more than descriptions that appear to be related, we need something like L-identity to guide us, otherwise we’re just begging the question as to whether two relata pick out the same phenomena.
'Brains' Post: 'Explaining What It's Like'
The latest post on Brains is relevant to our current discussion. Take a look...
Wednesday, April 18, 2007
Identity Theory, Behaviorism, etc.
Place distinguishes between mental concepts where some sort of "inner process story" is unavoidable [consciousness/sensation], and mental concepts [cognitive/volitional] where some sort of inner process story is avoidable, and an analysis of the concepts can be provided in terms of dispositions to behave. Is there anything to this distinction? Why would a behaviorist be inclined to maintain it? Would psychologists/philosophers make a similar distinction nowadays between these mental concepts (thought not in terms of dispositions to behave)? Did behaviorists deny that cognitive/volitional mental concepts can be analyzed in terms of brain processes? If so, isn't it weird that the identity theory came first for consciousness/sensation (which seem, to me, prima facie harder to analyze in terms of brain processes), and only later for cognition/volition?
Place's initial worry is that accepting inner processes entails dualism. Historically, is this because at the time inner processes were seen as mysterious, especially perhaps in the heyday of behaviorism?
Logic, ontology, and meaning:
Place points out two ways in which people have mistakenly dismissed the identity theory on logical grounds alone. I think I understand Place's argument for the mistake in the first way: (I don't think I'm setting this up any differently than Mike did, but I'll set it up again in case I made a mistake here that contributes to why I don't understand Place's argument for the mistake in the second way)
The mistake is in failing to distinguish between the 'is' of definition and the 'is' of composition. If we fail to make that distinction, then we have 2 (rather than 3) cases involving 'is':
1) 'x is y and nothing else' makes sense.
2) 'x is y and nothing else' is nonsense.
The mistake occurs in thinking that if x and y are logically independent, it can't be the case that 'x is y and nothing else' makes sense. Furthermore (here's where ontology kicks in), if 'x is y and nothing else' is nonsense, then x and y are ontologically distinct.
Once we make the distinction, we see that there are two ways for 'x is y and nothing else' to make sense. So even if we show that "consciousness" and "brain process" are logically independent, it can still be the case that "consciousness is a brain process and nothing else" makes sense.
But I am puzzled by the second way in which Place claims that people have mistakenly dismissed the identity theory on logical grounds alone. The second way involves the argument from the logical independence of two expressions to the ontological independence of the entities to which they refer. Place maintains that the argument works when Rule A (as Mike calls it) works, yet Rule A doesn't always work.
But I don't understand the role of Rule A in Place's argument. Place begins his article by stressing that "consciousness is a brain process" is definitely not a thesis about meaning. If so, we shouldn't be worried about cases where the expression used to refer to x doesn't entail the expression used to refer to y, right?
Mabye he's trying here to demonstrate why he is adamant about his article not being a thesis about meaning, but if so, what does this have to do with operations of verification? That is, I thought he already explained that "a cloud is a mass of tiny particles" contains an "is" of composition rather than definition, and this (rather than non-simultaneous verification) is why "there is nothing self-contradictory in talking about a cloud which is not composed of tiny particles in suspension." So, when it comes to clouds, lightning, and consciousness, it seems to me that these cases involving identity aren't breaking Rule A. Rather, these are simply cases involving the "is" of composition rather than definition.
So: What Place really seems to be worried about is how to maintain an identity statement in light of verification conditions that not only differ- as in the case of "cloud" and "mass of tiny particles"- but differ without continuity of observation. Am I wrong to think that this would appear to be an insoluble problem by behaviorists, and would be a motivation for them to focus entirely on behavior? And am I wrong to think that Place's solution (by ingenious analogy to lightning)- establish identity by showing that "introspective observations reported by the subject can be accounted for in terms of processes which are known to have occured in his brain"- lays a crucial foundation stone for post-behaviorist cognitive science?
If so, I conclude that Place's article is both messier (in terms of argument structure) and more important than I originally thought.
Place's initial worry is that accepting inner processes entails dualism. Historically, is this because at the time inner processes were seen as mysterious, especially perhaps in the heyday of behaviorism?
Logic, ontology, and meaning:
Place points out two ways in which people have mistakenly dismissed the identity theory on logical grounds alone. I think I understand Place's argument for the mistake in the first way: (I don't think I'm setting this up any differently than Mike did, but I'll set it up again in case I made a mistake here that contributes to why I don't understand Place's argument for the mistake in the second way)
The mistake is in failing to distinguish between the 'is' of definition and the 'is' of composition. If we fail to make that distinction, then we have 2 (rather than 3) cases involving 'is':
1) 'x is y and nothing else' makes sense.
2) 'x is y and nothing else' is nonsense.
The mistake occurs in thinking that if x and y are logically independent, it can't be the case that 'x is y and nothing else' makes sense. Furthermore (here's where ontology kicks in), if 'x is y and nothing else' is nonsense, then x and y are ontologically distinct.
Once we make the distinction, we see that there are two ways for 'x is y and nothing else' to make sense. So even if we show that "consciousness" and "brain process" are logically independent, it can still be the case that "consciousness is a brain process and nothing else" makes sense.
But I am puzzled by the second way in which Place claims that people have mistakenly dismissed the identity theory on logical grounds alone. The second way involves the argument from the logical independence of two expressions to the ontological independence of the entities to which they refer. Place maintains that the argument works when Rule A (as Mike calls it) works, yet Rule A doesn't always work.
But I don't understand the role of Rule A in Place's argument. Place begins his article by stressing that "consciousness is a brain process" is definitely not a thesis about meaning. If so, we shouldn't be worried about cases where the expression used to refer to x doesn't entail the expression used to refer to y, right?
Mabye he's trying here to demonstrate why he is adamant about his article not being a thesis about meaning, but if so, what does this have to do with operations of verification? That is, I thought he already explained that "a cloud is a mass of tiny particles" contains an "is" of composition rather than definition, and this (rather than non-simultaneous verification) is why "there is nothing self-contradictory in talking about a cloud which is not composed of tiny particles in suspension." So, when it comes to clouds, lightning, and consciousness, it seems to me that these cases involving identity aren't breaking Rule A. Rather, these are simply cases involving the "is" of composition rather than definition.
So: What Place really seems to be worried about is how to maintain an identity statement in light of verification conditions that not only differ- as in the case of "cloud" and "mass of tiny particles"- but differ without continuity of observation. Am I wrong to think that this would appear to be an insoluble problem by behaviorists, and would be a motivation for them to focus entirely on behavior? And am I wrong to think that Place's solution (by ingenious analogy to lightning)- establish identity by showing that "introspective observations reported by the subject can be accounted for in terms of processes which are known to have occured in his brain"- lays a crucial foundation stone for post-behaviorist cognitive science?
If so, I conclude that Place's article is both messier (in terms of argument structure) and more important than I originally thought.
Tuesday, April 3, 2007
The Phenomenological Fallacy
According to Place , if consciousness is a brain process, then the introspective observations reported by a subject must be accountable for in terms of brain processes. Place notes that, typically, the neuroscientists concern is not self-contradiction in asserting that consciousness is a brain process, but rather the apparent irreducibility of conscious states into the language used to describe well-known properties of the nervous system. As has been pointed out time and time again, there seems to be a fundamental disconnect there. This is a well-known concern of philosophers as well, cf. Jackson’s knowledge argument and other appeals to qualitative mental states as irreducible.
Place has a straightforward criticism of arguments from qualia that is interesting insofar as it doesn’t appeal to the functional role of any particular qualitative state, though it seems to hint in that direction. The Argument from Irreducibility, as I’ll call it, rests crucially on the following error in reasoning:
The Phenomenological Fallacy (PF)
When a subject s describes his ‘introspective’ observations of so-called qualitative states (i.e. his experience of looks, smells, sounds, feels, and other seemings), s describes literal properties of objects and events experienced in the ‘phenomenal field’.
The idea is that s reports on experiences that he is having in a kind of phenomenological theatre; reminiscent of the very Cartesian idea that the mind is necessarily better known than anything ‘external’ to the mind. What is the problem with this line of reasoning?
To use Place’s example, allow that s experiences a green after-image. s reports something like, ‘When I close my eyes I see a green object in front of me.’ The phenomenological fallacy is to claim that s literally experiences or actually sees a green object. Of course, such an object clearly does not correspond to any object in s’s environment, nor is likely to be manifest in any particular brain process where we to open up s’s head and look inside. Echoing the original argument from the conceptual independence of CONSCIOUSNESS and BRAIN PROCESS, the conclusion is just that COLOR, for instance, is not the sort of concept applicable to brain processes at all.
According to Place, here is the error: PF depends on the assumptions, more or less equivalent, that:
(1) Our ability to describe things in our environment depends on our consciousness of them.
(2) Our descriptions of things are primarily descriptions of our conscious experience and only inferentially descriptions of objects in the environment.
In effect, we infer real properties from phenomenal ones, but Place claims that the opposite is just the case. It is true that “We begin by learning to recognize the real properties of things in our environment.” But the fact that we learn to recognize real properties by the way they look, smell, etc. does not entail that we have to learn how to describe those looks, smells, tastes, etc. before we can describe the real objects themselves. It is simply a myth to assume that we describe experience with reference to phenomenal properties; rather we have from the beginning access to actual physical properties/objects. It is these real properties and objects that in turn ‘give rise’ to conscious experience we then try to describe.
So, to return to the subject s, when he says, ‘When I close my eyes I see a green object in front of me’, we should analyze this claim into, ‘When I close my eyes I have the sort of experience I normally have when I look at a green patch of light.’ The distinction is that the second claim makes it clear that there isn’t anything there, really: no green ‘object’. It is interesting to think about how this line of reasoning might apply to other phenomenal ‘objects’ and states. Place might be read as implying, for example, that pain would be somehow likewise ‘unreal’, or at least provide an interesting argument to the effect that pain is not an intentional object, as other have argued.
Now, Place’s argument seems to rest on some pretty substantial metaphysical/epistemological assumptions about the nature of objects and our access to those objects. But I’m sure there are some strategies to draw on there. What’s interesting to consider is the possibility that if we lose phenomenal objects (as they’re construed by the folks Place is concerned with), we may be free to posit the kind of identity Place wants. At least, there is nothing inconsistent or contradictory in saying for instance, that a particular experience of pain, or a green- after image is anything over and above a brain process. Again, if we can have contingent identity of the kind Place argues for early on, then the ‘irreducibility’ of the conscious states to physical states becomes a matter of a subject’s just not being able to verify the former introspectively. But we can’t learn the general identity of LIGHTNING and ELECTRIC CHARGES IN MOTION by introspection either.
Place has a straightforward criticism of arguments from qualia that is interesting insofar as it doesn’t appeal to the functional role of any particular qualitative state, though it seems to hint in that direction. The Argument from Irreducibility, as I’ll call it, rests crucially on the following error in reasoning:
The Phenomenological Fallacy (PF)
When a subject s describes his ‘introspective’ observations of so-called qualitative states (i.e. his experience of looks, smells, sounds, feels, and other seemings), s describes literal properties of objects and events experienced in the ‘phenomenal field’.
The idea is that s reports on experiences that he is having in a kind of phenomenological theatre; reminiscent of the very Cartesian idea that the mind is necessarily better known than anything ‘external’ to the mind. What is the problem with this line of reasoning?
To use Place’s example, allow that s experiences a green after-image. s reports something like, ‘When I close my eyes I see a green object in front of me.’ The phenomenological fallacy is to claim that s literally experiences or actually sees a green object. Of course, such an object clearly does not correspond to any object in s’s environment, nor is likely to be manifest in any particular brain process where we to open up s’s head and look inside. Echoing the original argument from the conceptual independence of CONSCIOUSNESS and BRAIN PROCESS, the conclusion is just that COLOR, for instance, is not the sort of concept applicable to brain processes at all.
According to Place, here is the error: PF depends on the assumptions, more or less equivalent, that:
(1) Our ability to describe things in our environment depends on our consciousness of them.
(2) Our descriptions of things are primarily descriptions of our conscious experience and only inferentially descriptions of objects in the environment.
In effect, we infer real properties from phenomenal ones, but Place claims that the opposite is just the case. It is true that “We begin by learning to recognize the real properties of things in our environment.” But the fact that we learn to recognize real properties by the way they look, smell, etc. does not entail that we have to learn how to describe those looks, smells, tastes, etc. before we can describe the real objects themselves. It is simply a myth to assume that we describe experience with reference to phenomenal properties; rather we have from the beginning access to actual physical properties/objects. It is these real properties and objects that in turn ‘give rise’ to conscious experience we then try to describe.
So, to return to the subject s, when he says, ‘When I close my eyes I see a green object in front of me’, we should analyze this claim into, ‘When I close my eyes I have the sort of experience I normally have when I look at a green patch of light.’ The distinction is that the second claim makes it clear that there isn’t anything there, really: no green ‘object’. It is interesting to think about how this line of reasoning might apply to other phenomenal ‘objects’ and states. Place might be read as implying, for example, that pain would be somehow likewise ‘unreal’, or at least provide an interesting argument to the effect that pain is not an intentional object, as other have argued.
Now, Place’s argument seems to rest on some pretty substantial metaphysical/epistemological assumptions about the nature of objects and our access to those objects. But I’m sure there are some strategies to draw on there. What’s interesting to consider is the possibility that if we lose phenomenal objects (as they’re construed by the folks Place is concerned with), we may be free to posit the kind of identity Place wants. At least, there is nothing inconsistent or contradictory in saying for instance, that a particular experience of pain, or a green- after image is anything over and above a brain process. Again, if we can have contingent identity of the kind Place argues for early on, then the ‘irreducibility’ of the conscious states to physical states becomes a matter of a subject’s just not being able to verify the former introspectively. But we can’t learn the general identity of LIGHTNING and ELECTRIC CHARGES IN MOTION by introspection either.
Sunday, April 1, 2007
Place's Analogy
I thought it was interesting for Place to make the following SAT style analogy: lightning is to motion of electric charges, as consciousness is to a certain brain process, in that the first term (lightning, consciousness) is the word used by the "man in the street" to describe a certain phenomenon, and the second term (motion of electric charges, certain brain process perhaps) is the more technical description of the causal connection between two non-independent events.
By adding this technical description, in light of certain discoveries, we presumably gain predictive powers. We now know the conditions under which flashes of lightning will be seen by people on the street, and this in turn provides a better explanation of why those flashes of lightning took place. I'm assuming that something like this is what we're looking for in the case of consciousness: We want to be able to know the conditions under which, I guess, people will report feelings of consciousness (or something else)? And we want a better explanation than people on the street can provide for why those feelings of consciousness take place. But is there a more concrete description of what it is we're trying to explain?
A final comment on the lightning analogy. Back in the day, before they knew with certainty that lightning is just the motion of electric charges, what were the possibilities involved in the scientific explanation of lightning actually is? And, to push the analogy, what have people thought are the possibilities involved in what consciousness actually is? Assuming that the word consciousness actually has a reference (sorry, I'm probably butchering the real philsophy of language involved here), could its reference be anything other than some sort of brain process?
By adding this technical description, in light of certain discoveries, we presumably gain predictive powers. We now know the conditions under which flashes of lightning will be seen by people on the street, and this in turn provides a better explanation of why those flashes of lightning took place. I'm assuming that something like this is what we're looking for in the case of consciousness: We want to be able to know the conditions under which, I guess, people will report feelings of consciousness (or something else)? And we want a better explanation than people on the street can provide for why those feelings of consciousness take place. But is there a more concrete description of what it is we're trying to explain?
A final comment on the lightning analogy. Back in the day, before they knew with certainty that lightning is just the motion of electric charges, what were the possibilities involved in the scientific explanation of lightning actually is? And, to push the analogy, what have people thought are the possibilities involved in what consciousness actually is? Assuming that the word consciousness actually has a reference (sorry, I'm probably butchering the real philsophy of language involved here), could its reference be anything other than some sort of brain process?
Subscribe to:
Posts (Atom)
