• bongo fury
    1.7k
    The concept of 'qualia' isn't all that useful for feeding a witting or unwitting dualism. More than twice as many philosophers use the concept of 'representation' to the same tragic end.
  • Harry Hindu
    5.1k
    To those asserting that there are "physical" brains that model, are at least admitting that there are models, but can't seem to explain where their modeling of other "brains"(?) ends and real "brains"(?) begin. Why is modeling your own brain and body states (first-person perspective) different than you modeling other people's brains and bodies (third-person perspective)?

    If the brain models, what you call a brain is a model, but of what exactly? How do you know that the brain you refer to isn't the model rather than what the model is of? If brains model body states then how do you know that the brain you are seeing isn't just the way your mind models other people's minds? What they are essentially saying is the brains of others that they perceive is their own mental model of other people's mental modeling. It must be models all the way down?

    Like I said before, third-person perspectives are simulated first-person perspectives. So if you are going to assert that the first-person perspective is an illusion, then you've just undermined all of your third-person perspectives and knowledge you've acquired by them - which is everything you know.

    Another strange inconsistency that I've noticed on the part of the Modelers is that they make the assertion that the self is only a model, and not also what is modeled, yet a brain isn't just a model, but also what is modeled.
  • Mww
    4.9k
    If perception organizes, what does the brain do?
    — Mww

    It's the brain that's doing it. Perception is a brain function.
    Kenosha Kid

    Oh.

    Ya know.....I’m in agreement pretty much down the line, these last few pages, with minor adjustments maybe. But this.....too far out for me.

    It escapes me completely, how sensory receptor stimuli perception in my skin, can be construed as a brain function in my head. Related, of course; similar, maybe, both respect natural law. Identical? Ehhhh.....beyond my comprehension.

    Causality for perception is very far removed from causality for brain function.

    Maybe I better understand your “collapsing”, insofar as combining perception with brain function, the need for language to make the difference between them intelligible, is eliminated. And while psychologically convenient, it is empirically disasterous.

    With that, I’m out.
  • fdrake
    6.7k
    No, this is a misrepresentation. Kenosha Kid is not suggesting that we're 'looking' at images of flowers, the 'looking' is the name we give to the entire process. What @Kenosha Kid is referring to is our responses. Speech, action, emotional responses, strategies, and more complex mental reactions. These all result from the perception of the flower, not the flower.Isaac

    @Kenosha Kid

    @Andrew M

    I think we all had the "does separating out experience from perception create a perceptual intermediary + invite the Cartesian theatre criticism" discussion before. Somewhere around page 30 here. @Jack Cummins may find the discussion of the article in that thread's OP useful.
  • Jack Cummins
    5.3k

    I am reading and thinking about the many replies on the thread, but a little perplexed as there are many responses and it is such a complex area of philosophy. The whole nature of perception in thinking about 'reality', and human experiences raises so much questioning about how human understanding goes, in understanding of what may be perceived and what may be the basis of underlying aspects of 'reality'.
  • Kenosha Kid
    3.2k
    It escapes me completely, how sensory receptor stimuli perception in my skin, can be construed as a brain function in my head.Mww

    Ah, I understand. I wouldn't call actual excitement of nerves in the skin perception, though. I think we're just using the terms differently. Perception is the brain organising data from our senses as I'm familiar with the word.
  • Kenosha Kid
    3.2k
    Just for clarity, that quote from me was not in response to that quote from Isaac.
  • Isaac
    10.3k
    and @fdrake

    This is where things are currently at

    https://www.biorxiv.org/content/biorxiv/early/2017/12/30/240317.full.pdf

    We need a kind of AI to 'learn' the translation as we go, without this in between step, there's nothing... yet.

    I have aphantasiaDawnstorm

    Ahh, well that is interesting! I don't know enough about the condition to even begin to discuss how the process I'm describing might affect you I'm afraid.

    It feels like I'm aware of what's going on in my head in somewhat the same way that I'm aware there are platypuses in Australia. External stuff experienced in the past; no situationally present trigger or connection. If I apply neuroscientific knowledge to myself then I objectify myself, and it's all theoretic.Dawnstorm

    Yep. Basically (for someone without aphantasia), your images of the rest of your room are constructed that way too, you 'know' where the wardrobe is in the same way (well, similar - I'm simplifying). You're constructing your awareness of the room in part out of stuff you know about the room, not photons from it hitting your retina.

    When you say decode, do you mean with loss? If so, what would be lost?fdrake

    Great question! I don't know enough about it to answer accurately, but, yes with loss (I've actually been shown some of the images, they just look like fuzzy versions of real pictures). As to what's been lost...my guess is there'd be three elements...

    1. Some raw data - capture isn't going to be perfect.
    2. Some secondary data - I don't know how the team are learning to distinguish data over the time series, which signals are being rejected under backward acting suppression by higher regions. If it simply learnt and re-iterated all the signals the result would be an absolute mess with all the neuronal noise and earlier modelling iterations.
    3. Data we thought was visual but turns out isn't - if we ever got a perfect decoding from the visual cortex, my guess is that it would still look 'slightly off' to us. I'd look at a rose, see the picture of the rose I was looking at and think "yeah...but not quite". I suspect we add a considerable amount of embellishment to even the simplest of images.

    Then I say, but there's a difference between me passively seeing something I cannot help but see on the one hand, and me either actively conjecturing or remembering by association some facts about what I see. And then I think you say that that's all we're doing anyway when constructing these representations.Kenosha Kid

    Oh dear, I'm becoming a bore.

    whatever I'm seeing _seems_ to come to me fully formed. It doesn't seem like it would benefit from deliberation.Kenosha Kid

    You'd be surprised. Priming experiments have got a bad rap (quite justifiably! Shockingly bad methodologies most of them), but the theory is not so wildly outrageous. The impact of deliberate thought on image processing is not unreasonable. Here's a not too awful paper in it https://pubmed.ncbi.nlm.nih.gov/26566137/

    efficiency I would imagine. It's much better for me to make decisions based on integrated, annotated, coloured-in if you will information. Same reason we do feature extraction and dimensionality reduction as part of preprocessing for training and using neural nets. Having to consciously parse raw data would render consciousness too slow to be useful.Kenosha Kid

    Yes, that's my take too, but V2 to hippocampus seems to buck that trend. The idea is that is possibly involved in early stage presentation of expectations from priors stored as memories of early perceptive features. The full paper is here https://www.nature.com/articles/nn.4284/
  • Mww
    4.9k
    I wouldn't call actual excitement of nerves in the skin perception,Kenosha Kid

    Like Michael Corleone, “just when I think I’m out, they pull me back in!!!!”

    Different senses have different kinds of receptors, so what name covers them all, if not perception?
  • Isaac
    10.3k
    Are you familiar?Enrique

    Not something I'm familiar with, I'm afraid. I will look it up.
  • Srap Tasmaner
    5k


    It seems the distinction wanted is not between 'direct' and 'indirect', but between 'inferential' and 'non-inferential' -- only those are terms more appropriate to knowledge than perception. And that suggests we're still circling around the problematic nature of empiricism, as a theory of knowledge.
  • frank
    16k
    Different senses have different kinds of receptors, so what name covers them all, if not perception?Mww

    The sensory side of the nervous system uses electrical discharges to communicate with the central nervous system, which is the brain and spinal cord.

    If we cut those lines, you won't be aware of any sensation.
  • Joshs
    5.8k
    Like I said before, third-person perspectives are simulated first-person perspectives. So if you are going to assert that the first-person perspective is an illusion, then you've just undermined all of your third-person perspectives and knowledge you've acquired by them - which is everything you knowHarry Hindu

    Excellent points. Dan Zahavi has made similar arguments against maintaining the neuro-representationalist idea of a veil separating ‘outer’ third personal from ‘inner’ first personal processes.

    “ Representationalism notoriously courts scepticism: Why should awareness of one thing (an inner object) enable awareness of a quite different thing (an external object), and how can we ever know that what is internally accessible actually corresponds to something external?

    “…it is hard to understand how one can motivate a general skepticism about perceptual experience on the basis of neuroscientific findings, since the latter – to some extent at least – presuppose the validity of the former. The main challenge, in short, is not how we can epistemically get out of the brain, but how we could possibly get into it in the first place. How do we at all know that there really is a brain? In order to enjoy any kind of initial plausibility, the neuro-representationalist account that we have been presented with must necessarily be half-baked. It asks us to abandon our naïve realism, our confidence in the objective existence of ordinary objects of experience, but it only does so half-heartedly.

    Since the whole theory is constructed around the workings of the brain, the model must presuppose that one worldly object is exempt from its skeptical concerns and that we can indeed observe and describe the brain as it really is. But if indeed the brain as discovered by science is ‘real' in the transcendent sense of the term, then it is hardly convincing that we stop there, claiming that of all we can see and perceive, only one single object, the brain, is ‘truly real' and not just a representation, perceived as it is in itself.”
  • Banno
    25.3k
    My contention was that there are good reasons to talk of properties of experience as opposed to objects because they're not the same.Kenosha Kid

    Again, nothing in what I have said goes against talk of the experience of flowers. That's a misunderstanding all your own.
  • Mww
    4.9k


    I understand all that, but isn’t what I want to know. Isn’t what I’m asking.
  • frank
    16k
    it is hard to understand how one can motivate a general skepticism about perceptual experience on the basis of neuroscientific findings, since the latter – to some extent at least – presuppose the validity of the formerJoshs

    I don't think anyone moves from scientific findings to global skepticism. Common sense tells you that a representational scheme is vulnerable to skepticism.
  • Enrique
    842
    Not something I'm familiar with, I'm afraid. I will look it up.Isaac

    The idea is that information more or less unconsciously ascends through areas responsible for particular processes such as recognition of lines, shapes, positions, objects etc. in the visual system, then somehow impinges upon a specially adapted neural network's CEMI field where percepts (if you don't want to talk about the quantum underpinnings, I won't get into it) are ultrasychronized on a relatively large scale via phase locking to contribute towards domains of the perceptual field which of course extensively integrate via synesthesia-like mechanisms. But I have trouble discerning where these CEMI fields might be located and thought perhaps you could have some ideas once you're familiar with the theory. That's assuming you even consider it plausible as I do. If not, I'd like to know why.
  • Joshs
    5.8k
    I don't think anyone moves from scientific findings to global skepticism. Common sense tells you that a representational scheme is vulnerable to skepticismfrank

    Yes, but Zahavi’s point is that a phenomenological approach is not vulnerable to skepticism( for the same reason that a Wittgensteinian approach is not).
  • frank
    16k
    Yes, but Zahavi’s point is that a phenomenological approach is not vulnerable to skepticism( for the same reason that a Wittgensteinian approach is not).Joshs

    Right. Phenomenology isn't as ambitious as science, tho.
  • Enrique
    842


    Also, if you want to comment on my active thread Uniting CEMI and Coherence Field Theories of Consciousness I'd be interested to get your opinion.
  • fdrake
    6.7k
    This is where things are currently at

    https://www.biorxiv.org/content/biorxiv/early/2017/12/30/240317.full.pdf

    We need a kind of AI to 'learn' the translation as we go, without this in between step, there's nothing... yet.
    Isaac

    Cheers.

    It seems a bit of a stretch to me to say the brain effectively contains images from the methods in the study. But thanks for presenting it. I think my grumblings would derail the thread. Nevertheless I've put them in this hidden box.

    Grumblings
    A few reasons:

    ( 1 ) since the model linking FMRI signals and the extracted feature from the layers doesn't seem to have a neural mechanism associated with it, the overall algorithm run doesn't have a demonstrated 'port to the wetware', so to speak. It doesn't seem established to run in the brain. I think it's thus evidence for the weaker claim that 'it's possible to reconstruct some images from fmri signals' rather than 'fmri signals encode images in a way similar to what is portrayed in the paper'

    ( 2 ) The subjective appraisal procedure for accuracy had a strange design and metric:

    For the subjective assessment, we conducted a behavioral experiment with another group of 9 raters (4 females and 5 males, aged between 19 and 36 years). On each trial of the experiment, the raters viewed a display presenting a reconstructed image (at the bottom) and two candidate images (at the top; its original image and a randomly selected image), and were asked to select the image similar to the one presented at the bottom from the two candidates. Each trial continued until the raters made a response. For both types of assessments, the proportion of trials, in which the original image was selected as more similar one was calculated as a quality measure.

    It measures which of two presented images was 'more similar' (subjectively) to the subjects (an ordinal value) and then the number of agreements was presented as a % accuracy. From the set up they described:

    In both objective and subjective assessments, each reconstructed image was tested with
    all pairs of the images among the same types of images (natural-images,
    geometric-shapes, and alphabetical-letters for images from the image presentation
    sessions, and natural-images and geometric-shapes for images from the imagery
    session ; e.g., for the test natural-images, one of the 50 reconstructions was tested with
    49 pairs consisted of one original image and another image from the rest of 49, resulting
    in 50 × 49 = 2,450 comparisons).

    Chance is 50% accuracy. Effectively this is a simulation of whether a human could relabel the image generated into the training data corresponding to the type of the original image -eg, inferred lion features with lions when given a single alternative. Considering the pixel crosscorrelation of test features and images was reported as 66%, even mildly increasing the number of comparison images (at the expense of 'complete cases' of comparisons) could very well undermine the claim to 95% accuracy.

    If you look at the images, you can do a fair guess of which image is in which labelled category from just the background and colour space (lions are kinda yellow). Willing to bet the similarity is a priming effect of seeing the images on the same screen rather than labelling the DNN's feature as a perceptual type. Eg which of the reconstructed images of subject 2 is a lion and which is a mouse without knowing which is which beforehand?

    I'm sure there's an argument there that perceptual feature visual content is not the same thing as an inferred label of the perceptual feature visual content - but that's an argument which should not have to happen. Should've been taken away in the controls of the subjective experiment - or run another to see if people labelling images with categories (is this brown smudge a lion or a mouse?) produces analogous accuracy measurements (and we all know it wouldn't based on the sample reconstructed images).

    ( 3 ) The experimental design is there to generate test and training data for the neural network, insert bucket of ecological validity concerns here. A person's brain processing is as much devoted to a single image at a time as is possible and they are stationary.

    ( 4 )
    For test datasets, fMRI samples corresponding to the same stimulus or imagery were
    averaged across trials to increase the signal-to-noise ratio of the fMRI signals. To
    compensate for a possible difference of the signal-to-noise ratio between training and
    test samples, the decoded features of individual DNN layers were normalized by
    multiplying a single scalar so that the norm of the decoded vectors of individual DNN
    layers matched with the mean norm of the true DNN feature vectors computed from
    independent 10,000 natural images. Then, this norm-corrected vector was subsequently
    provided to the reconstruction algorithm. See Supplementary Methods for details of the
    norm-correction procedure.

    Gives me the willies - is it normal to manipulate the test data in a manner you didn't do to the training data? Effectively what's been inferred on is the average FMRI space-time series, but the model was fit on non-averaged ones. At what point would that decision be made? Is it standard? Did I misread it?
  • Banno
    25.3k
    Here's a curious, invalid deduction that no one here would be silly enough to make:

    • One can take information from a visual cortex and reconstruct the image being viewed.

    Therefore,

    • the rest of the brain is looking at an image constructed by the visual cortex.

    This is of course a misuse of "looking at". What the rest of the brain is doing is using what is provided by the visual cortex. "Looking at" involves objects, light, eyes, visual cortex and the rest fo the brain working together.
  • bongo fury
    1.7k
    at an image constructed by the visual cortex.Banno

    Well said. But would you allow "at an image in the retina"?

    Isn't that the thin end of the wedge?
  • Jack Cummins
    5.3k

    I wonder so much about the retina and the brain in the whole process of perception. Personally, I have been to eye clinics, with a variety of eye problems and some unusual aspects showing up in eye scans. This was one of the underlying factors which lead me to consider the nature of perception and its physical basis. The eyes and the brain may say so much about the process of perception, including aspects of psychology and philosophy.
  • bongo fury
    1.7k
    Yes. I suppose for most optometrists the concept of a retinal image must be an everyday one.
  • Jack Cummins
    5.3k
    I am sure that my question is the most stupid and basic philosophy question ever asked but it, can be asked.What is a brain, as an aspect of processing reality and perception?
  • Jack Cummins
    5.3k

    Yes, the idea of the retina may be extremely important in the understanding of brain processes. I had never thought about it all until I was told that I had some underlying retinal abnormalities and read about how the retina is part of the brain. This lead me to wonder to what extent is the whole process of thinking and interpretation of experiences linked to the process of perception. It may be asked to what extent do the aspects of sensory awareness are influenced by cognitive aspects of understanding, or vice versa?
  • Tom Storm
    9.2k
    Hellen Keller managed to be a pretty interesting thinker despite being blind and deaf from birth.
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