Mental imagery as non-physical perception pt. 2

[AgnosticBoy]

Critics of scientific realism ask how the inner perception of mental images actually occurs. This is sometimes called the "homunculus problem" (see also the mind's eye). The problem is similar to asking how the images you see on a computer screen exist in the memory of the computer. To scientific materialism, mental images and the perception of them must be brain-states. According to critics, scientific realists cannot explain where the images and their perceiver exist in the brain. To use the analogy of the computer screen, these critics argue that cognitive science and psychology have been unsuccessful in identifying either the component in the brain (i.e., "hardware") or the mental processes that store these images (i.e. "software").

Source: https://en.wikipedia.org/wiki/Mental_image

I presented this argument a few months ago on this forum. I will play more of an information-seeking role here because I was left unsatisfied in the last thread. So again, I pose this challenge to materialists to use empirically-verifiable evidence to explain how or why mental images are physical when we DO NOT perceive them with our senses (hallucinations, dreams, etc).

Here's an easier way to put it:
1. Why aren't scientists able to observe our mental images (our hallucinations, dreams, etc) if they are physical?

2. Since perception involves our senses, then how am I able to perceive mental images without my senses?

I want scientifically verifiable peer-reviewed evidence-based answers to my questions. If you don't know, then just admit it. Don't simply tell me that scientists will figure it out - that's FAITH ... not scientific EVIDENCE.

[Monta]

[Replying to benchwarmer]


"Even when you are seeing a 'live image' your brain is simply taking signal data from your optic nerves and generating a mental picture of what's actually there using your brain. When your eyes are closed, it likely uses the exact same mechanism except with stored data. "

That may be in some cases but not others.
Young children with limited life experiences therefore no memory to draw from,
have most realistic dreams such as flying and visions of monsters
which they've never seen etc.

People in deep meditation or in hypnogogic states see clear images.

[DrNoGods]

[Replying to post 9 by AgnosticBoy]

Your question really strengthens my point. You don't even know what physical form this experience has but yet you assume it's "physical".

No ... I'm not assuming the" experience" is physical. My point was that the perception of the mental image is created by the interactions of physical components in the brain (neurons, memory, etc.). An idea is not a physical thing, nor is a thought. These are perceptions created by the brain functioning as it does. So my point was that a mental image seems to be the same kind of thing, as is consciousness, or at least there is no reason to believe that they are not since without a correctly functioning brain all of these things cease to exist. They are all perceptions of various types created by the functioning of the physical components of the brain.

The brain is a complicated system, and like any system the functions can be far greater than the individual physical components by themselves. It is no different than a car in that sense. The metal, glass and rubber components are useless for helping someone get from A to B until they are assembled in a specific way to make an automobile, and in that form they can carry out more complicated functions. The brain obviously is a very complicated system of neurons and their interactions, and that system can produce perceptions like mental images, ideas and thoughts from the physical components of the brain interacting with each other.

So I'm not assuming that a mental image itself is physical, but that the perception of the mental image is created by the physical components of the brain working as a system, just as with thoughts, ideas and even consciousness. When a brain is destroyed, so are all of these things.

[Divine Insight]

[quote="[url=http://debatingchristianity.com/forum
You seem to be shifting your position a bit. You posted a study that presumes that we experience image-like in our minds (which is the whole point of your posted study being about seeing our thoughts and using computer to show the images we're thinking), but now you're against it once I exposed a problem with your conclusion.

I'm not shifting my position at all. You just refuse to pay attention to what I've actually said. I said that it has been down "both ways". In some cases, there is activity in the visual area of the brain when people imagine seeing images. This is especially true when they are shown an image visually and then asked to recall the same image immediately afterward. The brain appears to recreate the original visual pathways in those cases.

Other experiments where they are attempting to record someone's dreams which are not made of recently viewed images, the situation changes.

So there's no shift in my position. Apparently it can be done both ways. In fact, in the case of the retina passing electrical signals to the visual part of the brain in the back of the head the question becomes, "Which is the actual screen?" The retina? Or the visual cortex at the back of the brain? If it's the visual cortex at the back of the brain then that "image" wouldn't appear to us to look anything at all like the image that lands on the retina. None the less, we could 'decode' that information by making a correlation between the retina and the visual cortex. In fact, this is the principle that would be used to make bionic eyes.

Reconstructing images from dreams would be far more complex, yet even that appears to be doable.

So there's no inconsistency in my position. There are simply many different things the brain can do. That's all.

I make no claims on how we perceive mental images other than the fact that we don't use our senses. We are perceiving (experiencing) something. This is the materialists time to offer some sensible scientifically verifiable answers.

If mental images are physical, as you claim, then I want to know why scientists can not directly observe them?

But you have just shot yourself in your own foot here. Scientists are learning how to directly observe how human brains create the perception of 'images'.

Keep in mind that it's YOU who is demanding that some visual images must exist in the brain. The scientists are way ahead of you. They are looking into what a brain actually does to cause the perception of an image. And that's really all that needs to be explained.

So you aren't even remotely grasping the ideas here when you continually demand that someone show where some actual images are within the brain. There is no need for any actual images when the eyeballs aren't being used.

The rest of your post continues to harp on a 'need' for a physical image in the brain. So at this point all I can say is that you are in denial of all previous conversations on this topic. There simply is no need for an actual physical image to exist in the brain when the brain is constructing the perception of seeing an image.

[AgnosticBoy]

That may be in some cases but not others.
Young children with limited life experiences therefore no memory to draw from,
have most realistic dreams such as flying and visions of monsters
which they've never seen etc.

People in deep meditation or in hypnogogic states see clear images.

Some are better than others at forming mental images. I'm sure it can be improved with practices like meditation.

[AgnosticBoy]

Your question really strengthens my point. You don't even know what physical form this experience has but yet you assume it's "physical".

No ... I'm not assuming the" experience" is physical. My point was that the perception of the mental image is created by the interactions of physical components in the brain (neurons, memory, etc.). An idea is not a physical thing, nor is a thought. These are perceptions created by the brain functioning as it does. So my point was that a mental image seems to be the same kind of thing, as is consciousness, or at least there is no reason to believe that they are not since without a correctly functioning brain all of these things cease to exist. They are all perceptions of various types created by the functioning of the physical components of the brain.

I think there are two main points to be addressed here, one about the perception and why you call it physical.

You say that the brain creates a "perception". But lets go into a little more detail about what the perception involves. I gather that perception is always of SOMETHING or there is content to it, whether it be of seeing a face, hearing a sound, touching something, etc. You don't want to say that we're perceiving "images" (although I only say that they're not physical images, but are image-like), but you do agree that there's SOMETHING that we're perceiving, correct? If not an image, what is that something? Why can't scientists observe it?

You also said that that perceptions are interactions of the brain. By that, I take it that you mean they're physical just as the interactions are. But this is where emergence comes in. Properties of a system need not remain in place throughout all levels. As you added later on your post, more features or functions can be added, but I'd also say that more structures (or lack thereof e.g. certain features of mind) can be added, as well. If you expect the properties at the lower level to carry on into every level of the system (reductionism), then you'll never explain consciousness due to some of the reasons I just explained.

[AgnosticBoy]

[quote="[url=http://debatingchristianity.com/forum
You seem to be shifting your position a bit. You posted a study that presumes that we experience image-like in our minds (which is the whole point of your posted study being about seeing our thoughts and using computer to show the images we're thinking), but now you're against it once I exposed a problem with your conclusion.

I'm not shifting my position at all. You just refuse to pay attention to what I've actually said. I said that it has been down "both ways". In some cases, there is activity in the visual area of the brain when people imagine seeing images. This is especially true when they are shown an image visually and then asked to recall the same image immediately afterward. The brain appears to recreate the original visual pathways in those cases.

Other experiments where they are attempting to record someone's dreams which are not made of recently viewed images, the situation changes.

So there's no shift in my position. Apparently it can be done both ways. In fact, in the case of the retina passing electrical signals to the visual part of the brain in the back of the head the question becomes, "Which is the actual screen?" The retina? Or the visual cortex at the back of the brain? If it's the visual cortex at the back of the brain then that "image" wouldn't appear to us to look anything at all like the image that lands on the retina. None the less, we could 'decode' that information by making a correlation between the retina and the visual cortex. In fact, this is the principle that would be used to make bionic eyes.

You can't blame me for seeing a little shift because your response to my OP questions involved posting a study that presumes we see images in our mind. The researchers had a program that would recreate the IMAGES that was thought to be in our minds. At least, the scientists and one of the studies your videos talk about are willing to accept that there's "visual content" to our thoughts. The rest of your comments regarding how mental imagery works are theoretical.

Here are some excerpts from some of the studies mentioned in your videos from post #2:

Neuroscientists generally assume that all mental processes have a concrete neurobiological basis. Under this assumption, as long as we have good measurements of brain activity and good computational models of the brain, it should be possible in principle to decode the visual content of mental processes like dreams, memory, and imagery.

Source: http://gallantlab.org/index.php/publica ... t-al-2011/

Here's more about the same study:

"However, the breakthrough paves the way for reproducing the movies inside our heads that no one else sees, such as dreams and memories, according to researchers."

Source: http://news.berkeley.edu/2011/09/22/brain-movies/

And in the dream studies, the scientists do presume that participants have "visual" dreams:

Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports.

Source: https://www.nature.com/news/scientists- ... ms-1.11625

Is there a world of difference between saying "visual content" and "images"? Why can't scientists directly observe the visual content that we're perceiving?

I make no claims on how we perceive mental images other than the fact that we don't use our senses. We are perceiving (experiencing) something. This is the materialists time to offer some sensible scientifically verifiable answers.

If mental images are physical, as you claim, then I want to know why scientists can not directly observe them?

But you have just shot yourself in your own foot here. Scientists are learning how to directly observe how human brains create the perception of 'images'.

When I learn something in class, the teacher already has the full curriculum, and all of the objectives are laid out and guaranteed to be reached. That is not the case for this topic because we don't know HOW we'll get to know about the brain and mental imagery. These scientists have no straightforward checklist, nothing to guarantee that we'll even get an answer, especially one that supports only materialism.

Keep in mind that it's YOU who is demanding that some visual images must exist in the brain. The scientists are way ahead of you. They are looking into what a brain actually does to cause the perception of an image. And that's really all that needs to be explained.

Perception of WHAT? I just quoted where the scientists presume that we experience or PERCEIVE "visual content". What else would you call an experience that involves seeing faces, colors, and at times being projected onto 3d environments like what happens with hallucinations?

If mental imagery is entirely physical, then scientists should absolutely be able to explain how physical processes in the brain lead to mental imagery. They absolutely should be able to directly observe what we're experiencing just like we can know about all of the visual content in a computer!!!

[Divine Insight]

If mental imagery is entirely physical, then scientists should absolutely be able to explain how physical processes in the brain lead to mental imagery. They absolutely should be able to directly observe what we're experiencing just like we can know about all of the visual content in a computer!!!

And your problem with this is what exactly? That science isn't moving along at the speed that you would like for it to move?

Science is in the process of explaining these various things. Your impatience for the precise explanations does not equate to a failure of science.

Moreover, you claims that no explanation can be had are extremely premature. Why should anyone waste their time arguing with you when you have absolutely nothing to offer but complaints that science isn't moving as fast as you would like?

Clearly science is making progress and they haven't even remotely suggested that they are up against any brick walls preventing them from moving forward.

So where do you get off acting like as if they are up against a brick wall when there is absolutely no indication that this is the case?

Your arguments are no different from the "God of Gaps" types of arguments. You are simply arguing that just because science hasn't ironed out all the details yet that this suggests there must be some other non-scientific and non-physical answer.

It's way too premature to be trying to make that argument.

Your objections to science are unwarranted. It's that simple. Especially when you don't even have an alternative answer to offer. Claiming that there must be some non-physical images somewhere in an unseen invisible world that the brain is accessing when we visualize an image in our minds is, quite frankly, absurd.

Not only is there no need to make such a wild speculation, but until you have actually explained how that could work it's nothing but empty hot air.

Face it, you have nothing to offer but a disgruntled attitude toward science.

[AgnosticBoy]

If mental imagery is entirely physical, then scientists should absolutely be able to explain how physical processes in the brain lead to mental imagery. They absolutely should be able to directly observe what we're experiencing just like we can know about all of the visual content in a computer!!!

And your problem with this is what exactly? That science isn't moving along at the speed that you would like for it to move?

Science is in the process of explaining these various things. Your impatience for the precise explanations does not equate to a failure of science.

Moreover, you claims that no explanation can be had are extremely premature. Why should anyone waste their time arguing with you when you have absolutely nothing to offer but complaints that science isn't moving as fast as you would like?

Clearly science is making progress and they haven't even remotely suggested that they are up against any brick walls preventing them from moving forward.

So where do you get off acting like as if they are up against a brick wall when there is absolutely no indication that this is the case?

Your arguments are no different from the "God of Gaps" types of arguments. You are simply arguing that just because science hasn't ironed out all the details yet that this suggests there must be some other non-scientific and non-physical answer.

It's way too premature to be trying to make that argument.

Your objections to science are unwarranted. It's that simple. Especially when you don't even have an alternative answer to offer. Claiming that there must be some non-physical images somewhere in an unseen invisible world that the brain is accessing when we visualize an image in our minds is, quite frankly, absurd.

Not only is there no need to make such a wild speculation, but until you have actually explained how that could work it's nothing but empty hot air.

Face it, you have nothing to offer but a disgruntled attitude toward science.

My approach on this thread is being a skeptic. I've asked materialist to justify their claim that all mental phenomena is physical, like 'mental imagery'. That does not require that I present any evidence but rather that materialists present evidence and so far they've failed. There is no scientific verifiable evidence that points to causation nor to the actual form or structure of mental images. The same big gap exists for consciousness. So what I'm left with here is agnosticism.

You go on to presume scientists will eventually discover the answer. You also accuse me of being impatient. I assume you know that potential future evidence does not justify CURRENT claims. I go by available evidence and not evidence that is hoped for. I'm just as unsatisfied as an atheist that goes to a Christian website and leaves with little to no solid answers - just the typical apologetic points. There are other reasons that I view materialism as being inadequate for this issue. I believe that there are good reasons to support other positions like emergent dualism. Besides the lack of evidence from materialism, other reasons are:

- We don't perceive mental images the same way we perceive real-world objects, which shows the two are not the same
- Mental images/consciousness lack physical characteristics, which of course goes with why they're objectively unobserved.
- Computers have shown that consciousness is not needed to perform many of our cognitive tasks. Hek, some of the behaviors performed while sleepwalking shows that, as well. So WHY does it exist?
- The trend in science is also moving away from explaining consciousness in a reductionistic way. Reductionism gives materialism explanatory power. Without it you have consciousness as emergent phenomena or as a fundamental property.

I'll let leading neuroscientist Dr. Christof Koch elaborate on the last point.
Consciousness: Confessions of a Romantic Reductionist (MIT Press) by Dr. Christof Koch:

Pg. 113

What became increasingly clear to me was that no matter what the critical neuronal circuits are, their identification will raise a fundamental problem that I first encountered in 1992

Pg. 114

After one such seminar, the late neurologist Volker Henn in Zürich asked a simple question: Suppose that all of Crick’s and your ideas pan out and that layer 5 cortical neurons in the visual cortex that fire rhythmically and that send their output to the front of the brain are the critical neural correlates of consciousness. What is it about these cells that gives rise to awareness? How, in principle, is your hypothesis different from Descartes’ proposal that the pineal gland is the seat of the soul? Stating that neurons firing in a rhythmic manner generate the sensation of seeing red is no less mysterious than assuming that agitations of animal spirits in the pineal gland give rise to the passions of the soul. Your language is more mechanistic than Descartes’—after all, three and a half centuries have passed—but the basic dilemma remains as acute as ever.In both cases, we have to accept as an article of faith that some type of physical activity is capable of generating phenomenal feeling.

I responded to Henn with a promissory note: that in the fullness of time science would answer this question, but for now, neuroscience should just press on, looking for the correlates of consciousness. Otherwise, the exploration of the root causes of consciousness would be needlessly delayed.[/color]

Yet Henn’s challenge must be answered. The endpoint of my quest must be a theory that explains how and why the physical world is capable of generating phenomenal experience. Such a theory can’t just be vague, airy-fairy, but must be concrete, quantifiable, and testable.

Pg. 119

There is a clear alternative to emergence and reductionism, compelling to a covert Platonist such as myself. Leibniz spelled it out in the early eighteenth century in the opening statements of his Monadology:

1. The MONAD, which we shall discuss here, is nothing but a simple substance that enters into composites—simple, that is, without parts.

2. And there must be simple substances, since there are composites; for the composite is nothing more than a collection, or aggregate, of simples.

This point of view does come with a metaphysical cost many are unwilling to pay—the admission that experience, the interior perspective of a functioning brain, is something fundamentally different from the material thing causing it and that it can never be fully reduced to physical properties of the brain.

I believe that consciousness is a fundamental, an elementary, property of living matter. It can’t be derived from anything else; it is a simple substance, in Leibniz’s words.

Pg. 120

And so it is with consciousness. Consciousness comes with organized chunks of matter. It is immanent in the organization of the system. It is a property of complex entities and cannot be further reduced to the action of more elementary properties. We’ve arrived at the ground floor of reductionism (that is why the reductionist of the subtitle of this book is tempered by the romantic).

Dr. David Chalmers believes consciousness is fundamental property of the universe and not just of a system like Dr. Koch believes.

[DrNoGods]

[Replying to post 15 by AgnosticBoy]

You don't want to say that we're perceiving "images" (although I only say that they're not physical images, but are image-like), but you do agree that there's SOMETHING that we're perceiving, correct? If not an image, what is that something? Why can't scientists observe it?

I wouldn't argue that we're not perceiving images ... just as in dreams. I'm a pretty good dreamer and have vivid, colorful dreams just about every night that I can remember details of the next day. But why do these, or other instances of mental image perception such as simply imagining something, need any special explanation beyond that they are perceptions created by the brain via its ability to assemble inputs from its components to create the experience?

If you consider experiences like happiness, surprise, or fear, etc., these are not physical "things" in the brain that can be measured by science as some sort of physical entity that exists somewhere in the brain. They are emotions or "feelings" that result from the physical components of the brain interacting in specific ways to produce the relevant perception. I don't see why the perception of mental images, or consciousness, would be any different. These are all emergent properties of the brain functioning as it does as a system.

There is no need to bring in some extra dimension or nonphysical explanation just because we can't yet explain the mechanisms at a molecular level.

[Divine Insight]

That does not require that I present any evidence but rather that materialists present evidence and so far they've failed.

But they haven't failed.

Just because you, or someone else, doesn't like their answers doesn't mean that they have failed.

In fact, if they are using brain activity to reproduce the images people are thinking about then I would say that they have totally succeeded. The resolution may be quite blurry right now, but technology always takes time to refine.

So to say that they have 'failed' is nonsense.

Not only this, but you speak of this as though you are engaging in some sort of war between "materialists" versus "spiritualists' or whatever.

Materialists are under absolutely no obligation to respond to any arguments or complaints made be spiritualists, because spiritualists haven't been able to demonstrate anything at all. Period.

I mean if you want to talk about failure, it's the position of spiritualism that has utterly failed.

If you can't explain how the mind or vision works from a non-physical spiritual position, then you aren't in any position to be suggesting that materialist have failed.

They can at least demonstrate that material exists. They are far ahead of you or any spiritualists to be certain.

So you aren't in a position to claim that materialists have 'failed' at anything.

What you are arguing for is absolute nonsense. Where's your evidence for the existence of something that doesn't exist? (i.e. non-material).

By definition, you are requiring that it can't exist. How could it exist if it's non-material?

You quite literally have "nothing" to offer.

Talk about failure.