tag:blogger.com,1999:blog-9192597712746432631.post9137858684505723248..comments2024-03-09T09:06:35.288+00:00Comments on Notes from Two Scientific Psychologists: Assume the Cow is a SphereAndrewhttp://www.blogger.com/profile/16732977871048876430noreply@blogger.comBlogger33125tag:blogger.com,1999:blog-9192597712746432631.post-80431887134022322552014-03-02T03:34:44.947+00:002014-03-02T03:34:44.947+00:00Interesting discussion (though I couldn't get ...Interesting discussion (though I couldn't get through all the comments). It may be true that philosophers should learn more of the empirical work, even though I think they are often underestimated on this. But there is a more general point. Empirical data is necessary for solving these problems, but it alone is not sufficient. That's is pretty much a truism by this point, I'd thought. The trick is seeing where exactly the data must (not just happens to) fall short of settling dispute, and to know what alternative is appropriate in that case. You might be interested in my paper "From cognition's location to the epistemology of its nature". It discusses one of the real cases that Andrew thinks is worthwhile, and shows why this and any data from it could never settle the dispute between extended and embedded cognition. Even the most careful experimentation can at best favor one causal hypothesis over another. To make the further leap to a constitutive claim, much more is needed. A.https://www.blogger.com/profile/16896901828046448265noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-44049701576041042652013-10-19T13:32:54.683+01:002013-10-19T13:32:54.683+01:00Sorry some superfluous "woulds" in there...Sorry some superfluous "woulds" in there, don't get lost!<br /><br />In addition a question, Ken, in what way is the coupling-constitution fallacy different from the "effect = structure" fallacy? That is, affirming the consequent? The latter applies to about all of empirical social science.Anonymoushttps://www.blogger.com/profile/01414244802603249395noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-72886950058118456602013-10-19T13:11:33.523+01:002013-10-19T13:11:33.523+01:00Gentlepeople,
as much as I enjoy these discussio...Gentlepeople,<br /><br /> as much as I enjoy these discussions and exchanges of "what if..." arguments, perhaps a meta-theoretical timeout is necessary.<br /><br />1.Ken, what would would be the empirical evidence that would convince you Andrew is right?<br />2. Andrew, what would would be the empirical evidence that would convince you Ken is right?<br /><br />Let's do that experiment in a context of strong inference!<br /><br />If no experiment empirical evidence exists that can distinguish between the verisimilitude of your claims they are:<br /><br />1. Similar - unification awaits, science advances. Waves, particles, you know the drill.<br /><br />2. Trivial - much more work is needed in order to meet conditions of strong inference and head to head collisions theoretical predictions. Like the cosmic strings and branes are beautiful mathematical metaphors, but not a part of empirical science yet.<br /><br />I believe it is likely the second option best describes the case, except perhaps that snare theory is a bad example: It is a formal, axiomatic deductive theory, it does make predictions, but they are not testable with currently available measurement devices. <br /><br />Ecological psychology has a great advantage here, many explicit postulates (e.g. of direct perception, intentional dynamics, ecological physics) have been formulated... after Gibson, the field progressed. Most of them can be found in these works:<br /><br />Kugler, P. N., Shaw, R. E., Vincente, K. J., & Kinsella-Shaw, J. (1990). Inquiry into intentional systems I: Issues in ecological physics. Psychological Research, 52(2), 98–121. doi:10.1007/BF00877518<br /><br />Shaw, R., Flascher, O., & Mace, W. (1996). Dimensions of Event Perception. In Handbook of perception and action (Vol. 1, pp. 345–295). New York: Academic Press.<br /><br />Turvey, M. T., & Shaw, R. E. (1999). Ecological foundations of cognition: I. Symmetry and specificity of animal-environment systems. Nov-Dec 1999. Journal of Consciousness Studies, 6(11-12), 95–110.<br /><br />Shaw, R. E., & Turvey, M. T. (1999). Ecological foundations of cognition: II. Degrees of freedom and conserved quantities in animal-environment systems. Nov-Dec 1999. Journal of Consciousness Studies, 6(11-12), 111–123.<br /><br />Further development didn't stop there, e.g. see Chemero's 2009 book.<br /><br /><br />I have yet to see a formal definition of internal representation, or cognition for that matter: Cognitivists should make a head start with *formalising* what is and what is not cognition, in what kind of system we may expect to observe cognitive phenomena and what the relevant levels of observation of that system are. Within this formalism, theories can compete for accuracy and precision of the phenomena it describes as relevant. This will immediately solve your prime number computing example.<br /><br />It may also solve the following: Is this droplet a cognitive agent? Are cognitive processes and computations going on inside its central processor? After all, it can find the shortest route through a maze! http://cen.acs.org/articles/88/i3/Chemotaxis.html<br /> <br /><br />About gestures + cognition: That's not nearly radical enough imo. Dynamics of angular velocity of finger movements predicts emergence of insight in problem solving: See Stephen, Dixon, Isenhower (2009) http://www.ncbi.nlm.nih.gov/pubmed/19968438<br />Anonymoushttps://www.blogger.com/profile/01414244802603249395noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-232208228234436642012-02-09T20:54:47.774+00:002012-02-09T20:54:47.774+00:00A question re your computer performing a task. I a...A question re your computer performing a task. I am interested to understand how this is clarifying your arguments. What part of this process are you respectively describing as cognition? Surely Andrew isn't claiming that the work if the computer is somehow extended cognition? Surely neither is Ken claiming that there cognition ends with decision to press the key. Is that Andrews point? I for one know (subjectively) that on many occasions i have had to continue to consider the impact on my ongoing cognitive process when a computer hasn't responded in get way i expected (resulting in hitting the key repeatedly harder). Unlike Andrew i think great truths can be unearthed through flights of fancy but like him at some point i think they need to be testable. Either through ingenious experimental design or through examination of existing evidence. It seems to me that an interesting discussion would be to fully understand where you respectively think cognition starts and finishes.even in the computer example. that surely should be testable. I suspect it might also make faster headway than (fascinating) argument about whether an illusion is trick on correct perception or computation error in brain cognition (if i got that summary right its a miracle).tevhudsonhttps://www.blogger.com/profile/13495487954762732111noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-27735971731505866652010-09-10T23:26:32.893+01:002010-09-10T23:26:32.893+01:00The cow joke is a classic and a good humor litmus ...The cow joke is a classic and a good humor litmus test.<br /><br />Never though of applying it to philosophers but it works.Slanthttp://slantacademia.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-39135891238382540532010-09-08T13:09:55.589+01:002010-09-08T13:09:55.589+01:00Well, identifying the trick/problem with the infor...Well, identifying the trick/problem with the information is the principled basis for rejecting the case as artificial. But yes.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-46406398191876174452010-09-08T11:25:03.169+01:002010-09-08T11:25:03.169+01:00So, what this seems to come down to is rejected th...So, what this seems to come down to is rejected the cases as they are artificial. The part about there being a "trick" does not seem to help.<br /><br />re b): I see your point. I should have thought of this. Thanks.Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-18384621051899392552010-09-08T08:19:08.740+01:002010-09-08T08:19:08.740+01:00a) Gibson certainly knew it - he made some himself...a) Gibson certainly knew it - he made some himself (mostly by accident as he tried not to - it's hard not to make a stimulus ambiguous, actually, when you try to control for things). His early slant perception work with texture gradients, for example, produced ambiguous information and people responded accordingly (ie with high variability). <br /><br />But a note: it's been 30 years since Gibson '79 and that's a lot of time for the details of lab psychology to have moved on from what Gibson was personally capable of building. <br /><br />b) I don't think there's any ambiguity in your amodal completion task, as I think I commented there. The visual information is perfectly coherent, but you can come to see it's incomplete as you explore the object. Not having access to everything right there and then is not the same as an illusion designed to never even offer the possibility of more complete/less ambiguous knowledge.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-70751822124546164962010-09-08T01:20:09.642+01:002010-09-08T01:20:09.642+01:00Sabethg,
I hope you do disagree with Andrew and co...Sabethg,<br />I hope you do disagree with Andrew and conclude that I have a counterexample to his task analysis line! =)Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-89708471027645173982010-09-08T01:18:57.150+01:002010-09-08T01:18:57.150+01:00"You can make an ambiguous stimulus in a lab ..."You can make an ambiguous stimulus in a lab (a pattern of sound that doesn't specify anything)."<br /><br />A) Does Gibson say this anywhere?<br /><br />B) Ok. So, what about the ambiguity of the simple amodal completion example I posted at my blog? (The occluded thing could be either circular or pac-mannish.) It that a "lab made" ambiguity?Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-12807947759009217792010-09-07T22:15:13.330+01:002010-09-07T22:15:13.330+01:00Hi Ken,
There seems to be some confusion here. I&...Hi Ken,<br /><br />There seems to be some confusion here. I'm weighing in on this particular post based on the computer example you provided and the general comments about the suitability of various examples or thought experiments. <br /><br />I haven't really been following what you and Andrew have been discussing elsewhere and Andrew and I don't necessarily agree about these things anyway. I was interested in thinking about the variety of ways in which these tasks differ to see if that clarified why the one example seemed less informative about embodiment. <br /><br />I'll have a read through the arguments you refer to (re: task analysis) and think about how/if that fits in with what I'm saying. In general, it's probably best to assume that Andrew and I are thinking about this stuff independently :)Sabrina Golonkahttps://www.blogger.com/profile/10484205507927422316noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-37154989493913412562010-09-07T21:52:35.559+01:002010-09-07T21:52:35.559+01:00But, I thought that the Gibsonian line was that th...<i>But, I thought that the Gibsonian line was that the stimulus isn't ambiguous per se. It is only ambiguous *given artificial restrictions on movement* or something like that. </i><br />You can make an ambiguous stimulus in a lab (a pattern of sound that doesn't specify anything). There's clearly an entire cottage industry around making stimuli just like this for research purposes. Gibson's ecological approach does, indeed, have problems dealing with evil psychology labs :) <br /><br />The stimulus can only specify if it is the result of lawful interactions with a regular world. These auditory illusions are sound but they do not specify anything - they contain no structure lawfully related to anything in particular.<br /><br />I'll leave Sabrina to defend her take.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-82342230566492226992010-09-07T21:13:11.143+01:002010-09-07T21:13:11.143+01:00Hi, Sabethg,
Here is what, from Andrew, I am taki...Hi, Sabethg,<br /><br />Here is what, from Andrew, I am taking aim at:<br /><br />"Step 1 is therefore do a task analysis, and identify what is required for an organism to do whatever it is you are trying to explain. Step 2 is to identify what is performing that work. If any of the necessary work is being done by something other than the brain, then it's surely game on as far as embodied cognition is concerned."<br /><br />I'm not sure of the way you guys want to work out the details, but I think the "logic of the case" is relatively straightforward. Maybe you can tell me how to do it.<br /><br />But, part of your reply here seems to be to pile on some additional conditions. You note, for example, that after the initial button pressing, you are irrelevant to the task. Agreed. But, Andrew did not have that as a condition earlier, right? You also seem to want to say something like, no sub-part of the task can be explained in terms of stimulus-response. But, Andrew did not have anything like that in his first pass, right?<br /><br />If you (or Andrew)want to abandon or refine what Andrew wrote initially, that's fine. Just let me know. After all, who dots all the i's and crosses all the t's the first time?Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-58708362644161699572010-09-07T20:50:49.347+01:002010-09-07T20:50:49.347+01:00I also have another example of amodal completion a...I also have another example of amodal completion at my blog. (It has video, which was kind of fun.) For my trick trick ... Claymation ...Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-6031915946544197592010-09-07T20:44:30.969+01:002010-09-07T20:44:30.969+01:00"It's a trick because sounds generally ar..."It's a trick because sounds generally aren't ambiguous like this"<br /><br />But, I thought that the Gibsonian line was that the stimulus isn't ambiguous per se. It is only ambiguous *given artificial restrictions on movement* or something like that. <br /><br />I'm drawing this from Gibson's discussion pp. 166-8 of Gibson, (1979), regarding the trapezoids. There he seems to me to be saying that the reason the various trapezoids seem equivalent, or that there is some ambiguity, is that one is restricted to "peephole" vision. (Cf. especially, the first paragraph of p. 168).<br /><br />It seems to me that once one concedes that there is ambiguity in the stimulus and that there are individual differences, one is opening to door to the kinds of "presuppositions" that Gibson was against admitting.Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-88844441018337419592010-09-07T11:57:06.377+01:002010-09-07T11:57:06.377+01:00I think it's necessary to be specific about wh...I think it's necessary to be specific about what the task is. I could use a computer to solve an equation or I could solve it myself. The outcome is the same in either case, but the task is different. And, the computer is obviously solving the equation differently than I would, so the processes are also divergent. Now, there are some things a computer can solve that I can't (like computing primes). When I press the button to execute the program, I am involved in some kind of stimulus - response relationship. I don't care by what process the computer arrives at the result. I have learned an association between button pressing and getting a desired outcome. To my mind, this is like training pigeons to peck at the blue light to get food. My own cognitive state in this task is pretty irrelevant. I could know a lot about math or nothing at all. I could be pressing the button because someone asked me to or because I wanted to press a different button but made a mistake. I could be drunk, sober, 2 years old or 100. I could get my cat to push the button. The task is accomplished equally well in all these cases. Furthermore, after my initial button pressing, I am irrelevant to this process. If the computer takes 10 minutes to provide a solution that's fine. I can do something else and the program keeps ticking away. This seems very different from using a pencil and paper to work out an algebra problem (something I certainly but under the "embodied cognition" banner). This task cannot be explained in terms of stimulus - response. And, it cannot be localised in either my head or the environment. The task only exists as a system. Furthermore, the success of this venture depends on my particular cognitive state - I must be at least pretty sober, I have to know something about math, I have to be sufficiently awake and free from other distractions. And, success depends on the environment - the pencil has to have lead, the paper needs to be large enough, it must be dry, there must be a surface for me to bear down on. Finally, if I walk away from this system, it ceases to function and if someone takes my pencil and paper away the system ceases to function. A single outcome (getting the answer to an algebra problem) can be arrived at using multiple tasks (a computer, working it out by hand). However, these tasks seem to be fundamentally different. I think it's perfectly reasonable to want an explanation for what's going on in the computer example, but it's not the same type of task. Now, whether this rules embodiment out completely, I don't know. I think that essentially all of our cognition is grounded in embodiment to some extent. I find the notion of something being purely cognitive puzzling.Sabrina Golonkahttps://www.blogger.com/profile/10484205507927422316noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-54458839787711198702010-09-07T11:36:33.384+01:002010-09-07T11:36:33.384+01:00I'm not 100% sure what's going on in the s...I'm not 100% sure what's going on in the signal. There are two channels, each playing the same two-word sequence, at some temporal offset? Is that right? And different people hear different things?<br /><br />Is it ironic that I only hear that mp3 saying "no way" over and over? :)<br /><br />At a first pass, reading that website: the trick is at least partly the fact that the sound is designed to be ambiguous (no unique identity). This ambiguous signal then encounters a trained auditory system and the ambiguity is resolved in various ways, constrained by individual differences in the system's training. <br /><br />It's a trick because sounds generally aren't ambiguous like this; sound, like light, is lawfully structured by it's interactions with the world (say a vocal tract) and this kind of ambiguity is hard to come by in a real system lawfully producing sounds. Handing this signal to an auditory system trained with real sound might reveal a boundary condition or two but, like visual illusions, it's not clear what it tells you about speech perception in general.<br /><br /><b>This is very much a first pass, though</b> - I need to think about this some more. I'm not an expert in audition and I'm not clear on the details of how these were created. If anyone else wants to weigh in, please do!! But the analysis must always be rooted in the information: what spatial-temporal information is actually in the signal?<br /><br />I need to think some more, too, about your second post. Sabrina and I were throwing ideas around this morning but I need to firm them up.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-78243561579081882372010-09-07T10:52:03.636+01:002010-09-07T10:52:03.636+01:00In truth, I think I have been too agreeable in cha...In truth, I think I have been too agreeable in changing examples. I could, of course, tone down some of the more extreme features of the computer use example to make the main point. <br /><br />Suppose a person uses a computer to perform a task that she could not solve otherwise. It looks like hitting the button on the computer is necessary and sufficient for solving the task. So, it looks like, by Andrew's analysis, we have extended cognition.<br /><br />Now, you can say you don't care about this kind of case, but there is something going on in this case and a scientist might want to know about it. How should a scientist theorize about this? Should a scientist just ignore this? Just throw up her hands?Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-48628763090022261532010-09-07T10:29:28.266+01:002010-09-07T10:29:28.266+01:00Ok. So, even auditory illusions involve some tric...Ok. So, even auditory illusions involve some trick. So, what is the trick in this illusion?<br /><br />http://philomel.com/mp3/phantom_words/ex/phantom_words_ex1.mp3<br /><br />http://philomel.com/phantom_words/phantom.phpAnonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-76457568913274797322010-09-07T09:56:50.900+01:002010-09-07T09:56:50.900+01:00I don't mind the use of examples, per se, but ...I don't mind the use of examples, per se, but they need to be apt. Imagine that someone is arguing that human beings are remarkably well adapted to life on earth. A counter-example might be that humans can't live (in the ancestral sense) on the majority of the planet (e.g., in the ocean or on the tops of mountains). But this counter-example is not apt. It misses the fact that humans are only well-suited to live on earth within certain parameters (e.g., dry land, fresh water). In other words, our suitability to life on earth has a specific scope. Examples that exceed that scope are not informative about the problem. I think this is the critical issue with some thought experiments. If those examples don't reflect what we know from psychological research, then they risk exceeding the scope of the problem and being irrelevant.Sabrina Golonkahttps://www.blogger.com/profile/10484205507927422316noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-37330957141318825122010-09-07T09:20:15.447+01:002010-09-07T09:20:15.447+01:00But spherical cows are such fun to think about! Th...But spherical cows are such fun to think about! They must roll down the fields and fart their way up the hills - oh and isn't global warming from methane very suggestive that cows are, in fact, spherical on some level? <br /><br />You are right, this does happen, and yet, I'm glad we have Judith Jarvis Thomson's violinist to help us with one of the hardest choices. <br /><br />The joy of imagining in strange and careful detail is one of the things I loved the most about doing philosophy; little wonder I spent time doing it, and can it just be that pleasure that makes me so sure it's sometimes done well? Some people who still do philosophy properly might be keen to think about good vs. bad thought-science. Me, I'd rather consider the insemination of the spherical cows.Susanhttp://susanharper.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-72320433087814272202010-09-06T20:20:44.092+01:002010-09-06T20:20:44.092+01:00I guess I am challenging philosophy in general. I ...I guess I am challenging philosophy in general. I really do think spherical cows are a problem, actually, and I've thought this for a long time. I guess I was just apologising in case I was being a dick :)<br /><br />All illusions do depend on a trick. They depend on the source providing the observer with information that tells you one thing at one point in space and time and something else at another, in a way that non-illusory things don't do. Gibson gets specification from optics because of the natural laws underpinning the creation of information about the world; things we consider illusions are local breakings of those ecological laws.<br /><br />What I mean be 'laws' comes from Turvey et al's reply to Fodor & Pylyshyn, which I've discussed and referenced <a href="http://psychsciencenotes.blogspot.com/2010/03/poverty-of-stimulus-and-ecological-laws.html" rel="nofollow">here</a>. If you're interested but can't access the paper let me know.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-39422445075808007402010-09-06T17:55:09.440+01:002010-09-06T17:55:09.440+01:00Hi, Andrew, regarding thought experiments, it seem...Hi, Andrew, regarding thought experiments, it seems to me that you are not merely challenging me, but you are challenging the whole philosophical enterprise. But, philosophers are hugely mixed bag. Some seem to positively abhor scientific evidence, while others try pretty hard to keep themselves informed and make scientifically informed contributions. I happen to be in the camp that throws in with trying to be scientifically informed.Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-23468559056376620492010-09-06T17:49:03.079+01:002010-09-06T17:49:03.079+01:00Ok. I read the post and it helps me articulate my...Ok. I read the post and it helps me articulate my concern. You write<br /><br />"All visual illusions depend on a trick to work. The Ames Room, for example, is a trick of static perspective depth information that only works from one location; moving from there breaks the illusion, although it is compelling when you're in the right place. "<br /><br />Now, do you (or Gibson) want to go even further and claim that all illusions depend on a trick? If so, then what is the trick in the auditory illusions? (It's apparently not a constraint on movement, right?)Anonymoushttps://www.blogger.com/profile/08539727534751588479noreply@blogger.comtag:blogger.com,1999:blog-9192597712746432631.post-37788401435277335712010-09-06T13:36:37.720+01:002010-09-06T13:36:37.720+01:00OK, illusions:
Of the Ames room, Gibson suggests t...OK, illusions:<br /><i>Of the Ames room, Gibson suggests that this is a kind of artificial byproduct of non-natural viewing conditions. And, he in fact, it seems to me, suggests that all visual illusions are like this.<br /><br />Ok. So, what of auditory illusions? These do not seem to be the product of restricted listening conditions.</i><br />First, let me point you to <a href="http://psychsciencenotes.blogspot.com/2010/04/note-on-holt-on-visual-illusions-heft.html" rel="nofollow">this blog post</a> where I think out loud about this in some more detail.<br /><br />The Gibsonian analysis always rests on <b>information</b>. To call something an illusion suggests a failure of correspondence between what is happening in the world and what is happening in perceptual experience. For Gibson, however, correspondence isn't the game. Visual illusions aren't so much errors as specific situations in which the visual information leads to an inconsistent experience. <br /><br />The Ames room is a good example: from one specific location, the static perspective structure leads to the true visual experience of a square room. The fact that the room isn't actually square is besides the point: you never ever get to 'look behind the curtain', you only ever have information. The Ames room is revealed as an "illusion" by moving from that one spot, which provides you with a new, equally correct visual experience based in new information. Gibson treats this more temporally extended experience as reflecting the more fundamental nature of perception.<br /><br />Auditory illusions are then amenable to the same analysis: what information is in the signal and what happens to it as we explore? <br /><br />Gibson was grumpy about illusions because he was rejecting the idea that perception is for gaining access to some 'veridical' knowledge of the world. Perception is about information, and information is about affordances, which means that information is task-specific, organism relative, etc. A simple example: when reaching for my coffee cup I'm not perceiving metric distance per se, I'm perceiving distance with respect to my reaching capabilities. <br /><br />There is the world; there is information that specifies the world; perception occurs on the basis of information, and perceptual experience is the true experience of perceiving that information. If you find an 'error', look to the information.Andrewhttps://www.blogger.com/profile/16732977871048876430noreply@blogger.com