if perception is a brain function, then it has lost its established meaning,
— Mww
(...) Can you cite the established meaning? — Kenosha Kid
None of this is to say I am dubious about the existence of any object that purportedly causes my perception of it. — Kenosha Kid
Nonetheless, I am proceeding only in extremely high confidence in the hypothesis that my experience of the red flower is caused by an external object with certain properties that cause that experience. — Kenosha Kid
nothing of the external world is, for instance, in my brain. — Kenosha Kid
We're probably going far too deep into what is essentially a complaint that the term 'sense-datum' has already been taken and can't, for weird reasons, be transported between theories, or between a theory and a more descriptive discussion, leading to a proliferation of terminology and an inability to define clearly where one ends and another begins. — Kenosha Kid
leading to a proliferation of terminology and an inability to define clearly where one ends and another begins. — Kenosha Kid
An example would be a more complete theory that can account for the existence or illusion of sense data and qualia. This would be as opposed to one that shows that such ideas are purely artefacts of bad stroky bearding. — Kenosha Kid
If you take MP to be suggesting that either qualia or sense data are illusions — frank
Good point but the nonphysicalist has to admit s/he can't explain qualia in nonphysical terms and now we're in neti neti territory, Where do we go from here, sir/madam? — Agent Smith
What use are the senses without cogitation? What use is cogitation without senses? Brains evolved later from nerve nets. Feelings existed before integrating them into the whole of the brain.Well the senses themselves don't cogitate. So there's no puzzle by itself here. — Manuel
Not sure how reading what other people write can shed light on your own mind. Seems to me that the mind is fundamental and anyone that has one can reflect on its properties themselves without being influenced by what other people write. I come here to discuss with fellow free-thinkers that can think for themselves and come to their own conclusions, and not only about what other people write.I said "reading", not "watching videos". I come here to discuss with fellow well-read members, Harry, not to teach anyone what they can learn themselves. There's just too much 'idle (uninformed) speculation driven by intellectual laziness' going on lately. — 180 Proof
When I perceive a thing such as a fireplace, it is not the concordance of its various
appearances that leads me to believe in the existence of the fireplace as the geometrical plan
and common signification of all of these perspectives. On the contrary, I perceive the thing
in its own clarity (PP 191).
The constancy of colour is merely an abstract moment of the constancy of things, and the
constancy of things is established upon the primordial consciousness of the world as the
horizon of all our experiences (PP 326)
At the outset of the study of perception, we find in language the notion of sensation, which seems immediate and obvious: I have a sensation of redness, of blueness, of hot or cold. It will, however, be seen that nothing could in fact be more confused, and that because they accepted it readily, traditional analyses missed the phenomenon of perception (PP50)
Pure sensation will be the experience of an undifferentiated, instantaneous, dotlike impact. It is unnecessary to show, since authors are agreed on it, that this notion corresponds to nothing in our experience, and that the most rudimentary factual perceptions that we are acquainted with, in creatures such as the ape or the hen, have a bearing on relationships and not on any absolute terms. (PP51)
The pure quale would be given to us only if the world were a spectacle and one’s own body a mechanism with which some impartial mind made itself acquainted.3 Sense experience, on the other hand, invests the quality with vital value, grasping it first in its meaning for us, for that heavy mass which is our body, whence it comes about that it always involves a reference to the body (PP176).
I ain't. AFAIK he has a pretty realist take towards phenomena, but doesn't take a realist stance toward qualia and their 'experiential chunk' substrates. He has an issue with colour as a property of an experience, not with phenomena and colour. — fdrake
You're loading the term "qualia" with some sort of absolute independence. MP would say that nothing that's phenomenally accessible to us has that status.
If you insist that qualia must be this odd metaphysically independent entity, you're making the word useless for yourself and those who use it that way.
It remains an innocuous way to talk about the phenomenal character of consciousness for everyone else. — frank
What use are the senses without cogitation? What use is cogitation without senses? Brains evolved later from nerve nets. Feelings existed before integrating them into the whole of the brain. — Harry Hindu
“The light of a candle changes its appearance for a child when, after a burn, it stops attracting the child’s hand and becomes literally repulsive.2 Vision is already inhabited by a meaning (sens) which gives it a function in the spectacle of the world and in our existence. The pure quale would be given to us only if the world were a spectacle and one’s own body a mechanism with which some impartial mind made itself acquainted.3 Sense experience, on the other hand, invests the quality with vital value, grasping it first in its meaning for us, for that heavy mass which is our body, whence it comes about that it always involves a reference to the body. (P176 quote extended)
(P53/P54, bold and italics are mine)“The perceptual ‘something’ is always in the middle of something else, it always forms part of a ‘field’. A really homogeneous area offering nothing to be cannot be given to any perception. The structure of actual perception alone can teach us what perception is. The pure impression is, therefore, not only undiscoverable, but also imperceptible and so inconceivable as an instant of perception. If it is introduced, it is because instead of attending to the experience of perception, we overlook it in favour of the object perceived. A visual field is not made up of limited views. But an object seen is made up of bits of matter, and spatial points are external to each other. An isolated datum of perception is inconceivable, at least if we do the mental experiment of attempting to perceive such a thing. But in the world there are either isolated objects or a physical void.”
“I shall therefore give up any attempt to define sensation as pure impression. Rather, to see is to have colours or lights, to hear is to have sounds, to sense (sentir) is to have qualities. To know what sense-experience is, then, is it not enough to have seen a red or to have heard an A? But red and green are not sensations, they are the sensed (sensibles), and quality is not an element of consciousness, but a property of the object. Instead of providing a simple means of delimiting sensations, if we consider it in the experience itself which evinces it, the quality is as rich and mysterious as the object, or indeed the whole spectacle, perceived. This red patch which I see on the carpet is red only in virtue of a shadow which lies across it, its quality is apparent only in relation to the play of light upon it, and hence as an element in a spatial configuration. ”
Analysis, then, discovers in each quality meanings which reside in it. It may be objected that this is true only of the qualities which form part of our actual experience, which are overlaid with a body of knowledge, and that we are still justified in conceiving a ‘pure quality’ which would set limits to a pure sensation. But as we have just seen, this pure sensation would amount to no sensation, and thus to not feeling at all. The alleged self-evidence of sensation is not based on any testimony of consciousness, but on widely held prejudice. We think we know perfectly well what ‘seeing’, ‘hearing’, ‘sensing’ are, because perception has long provided us with objects which are coloured or which emit sounds. When we try to analyse it, we transpose these objects into consciousness. We commit what psychologists call ‘the experience error’, which means that what we know to be in things themselves we immediately take as being in our consciousness of them. We make perception out of things perceived.
How on earth do you not see that he's saying that perception is infused with ideas? — frank
Take it as a given that we see colors, hear sounds, feel pains and see how to fit that with the rest of our understanding of the world. — Marchesk
It's a unit of pure sensation. Which is a category he undermines repeatedly. Pure sensation I take as meaning intrinsic, nonrelational properties of (hypothetical/criticised) sensory units. — fdrake
What's a holistic conception of qualia? — frank
MP is saying that a black dot, for instance, can't be perceived in isolation. There has to be something non-black around it.
This is an insight much older than MP. It at least goes back to Hegel. MP is just taking the time to apply the principle to perception. So if he's identifying an illusion, it's that a bit of perception could be independent. — frank
"Qualia as phenomenal character. Consider your visual experience as you stare at a bright turquoise color patch in a paint store. There is something it is like for you subjectively to undergo that experience. What it is like to undergo the experience is very different from what it is like for you to experience a dull brown color patch. This difference is a difference in what is often called ‘phenomenal character’. The phenomenal character of an experience is what it is like subjectively to undergo the experience. If you are told to focus your attention upon the phenomenal character of your experience, you will find that in doing so you are aware of certain qualities. These qualities — ones that are accessible to you when you introspect and that together make up the phenomenal character of the experience are sometimes called ‘qualia’. C.S. Peirce seems to have had something like this in mind when he introduced the term ‘quale’ into philosophy in 1866 (1866/1982, para 223)." — frank
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 — Enrique
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. — Enrique
I have trouble discerning where these CEMI fields might be located and thought perhaps you could have some ideas... — Enrique
...once you're familiar with the theory. — Enrique
It seems a bit of a stretch to me to say the brain effectively contains images from the methods in the study. — fdrake
I think my grumblings would derail the thread. Nevertheless I've put them in this hidden box. — fdrake
( 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' — fdrake
( 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). — fdrake
( 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. — fdrake
( 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? — fdrake
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