Is our vision of reality correct? (Introduction)
by David Turell 
, Monday, October 26, 2015, 23:28 (3315 days ago)
Michael Shermer thinks it is, and I agree with him:-http://www.scientificamerican.com/article/did-humans-evolve-to-see-things-as-they-really-are/?WT.mc_id=SA_EVO_20151026-"Over the millennia philosophers have offered many theories, from solipsism (only one's mind is known to exist) to the theory that natural selection shaped our senses to give us an accurate, or verdical, model of the world. Now a new theory by University of California, Irvine, cognitive scientist Donald Hoffman is garnering attention. (Google his scholarly papers and TED talk with more than 1.4 million views.) Grounded in evolutionary psychology, it is called the interface theory of perception (ITP) and argues that percepts act as a species-specific user interface that directs behavior toward survival and reproduction, not truth.-"Hoffman's computer analogy is that physical space is like the desktop and that objects in it are like desktop icons, which are produced by the graphical user interface (GUI). Our senses, he says, form a biological user interface—a gooey GUI—between our brain and the outside world, transducing physical stimuli such as photons of light into neural impulses processed by the visual cortex as things in the environment. GUIs are useful because you don't need to know what is inside computers and brains. You just need to know how to interact with the interface well enough to accomplish your task. Adaptive function, not veridical perception, is what is important.-***-"ITP is well worth serious consideration and testing, but I have my doubts. First, how could a more accurate perception of reality not be adaptive? Hoffman's answer is that evolution gave us an interface to hide the underlying reality because, for example, you don't need to know how neurons create images of snakes; you just need to jump out of the way of the snake icon. But how did the icon come to look like a snake in the first place? Natural selection. And why did some nonpoisonous snakes evolve to mimic poisonous species? Because predators avoid real poisonous snakes. Mimicry works only if there is an objective reality to mimic.-*** "Also, computer simulations are useful for modeling how evolution might have happened, but a real-world test of ITP would be to determine if most biological sensory interfaces create icons that resemble reality or distort it. I'm betting on reality. Data will tell.-"Finally, why present this problem as an either-or choice between fitness and truth? Adaptations depend in large part on a relatively accurate model of reality. The fact that science progresses toward, say, eradicating diseases and landing spacecraft on Mars must mean that our perceptions of reality are growing ever closer to the truth, even if it is with a small “t.”"-Comment: It is not often I agree with Shermer but he is right on. Unless our vision/brain apparatus gives us reality as it IS, we could not make the progress in knowledge we have made.
Is our vision of reality correct?
DAVID: Michael Shermer thinks it is, and I agree with him:-http://www.scientificamerican.com/article/did-humans-evolve-to-see-things-as-they-reall...-David's comment: It is not often I agree with Shermer but he is right on. Unless our vision/brain apparatus gives us reality as it IS, we could not make the progress in knowledge we have made.-I also agree, and we have discussed this many times in a variety of contexts. We can never know the objective truth, and the nearest we can get to it is through general consensus, but scientific testing and technology provide us with plenty of evidence that at least some of our perceptions are accurate.
Is our vision of reality correct?
by David Turell , Tuesday, October 27, 2015, 19:21 (3314 days ago) @ dhw
> dhw: I also agree, and we have discussed this many times in a variety of contexts. We can never know the objective truth, and the nearest we can get to it is through general consensus, but scientific testing and technology provide us with plenty of evidence that at least some of our perceptions are accurate.-I would say most of our perceptions are accurate.
Is our vision of reality correct? color perception
by David Turell , Thursday, January 11, 2018, 18:56 (2507 days ago) @ David Turell
In this article the point is made that color is really not a property of an object so much as it is how the brain perceives it:
http://nautil.us/issue/56/perspective/the-reality-of-color-is-perception-rp?utm_source=...
"My response is to say that colors are not properties of objects (like the U.N. flag) or atmospheres (like the sky) but of perceptual processes—interactions which involve psychological subjects and physical objects. In my view, colors are not properties of things, they are ways that objects appear to us, and at the same time, ways that we perceive certain kinds of objects. This account of color opens up a perspective on the nature of consciousness itself.
***
"Modern science, as inherited from the 17th century, gives us a perspective on material objects that is radically different from our ordinary sensory one. Galileo tells us that the world contains “bodies” which have properties like size, shape, and movement, regardless of anyone perceiving them. By measuring and describing things in terms of those “primary” properties, science promises to give us knowledge of the objective world, the world as it is independently of the distortions of human perception. Science can explain how it is that the molecules released into the air by a sage plant could stimulate my nose, or how its petals could reflect light and appear blue-violet to my eye. But the scent and the color itself—the conscious, sensory experience of them—make no showing in that explanation.
"The problem of color as we know it today is an ontological issue, a question about what there is in the universe. With the scientific worldview it becomes commonplace to say that the only properties of objects that are unquestionably real are the ones described in physical science. For Galileo they were sizes, shapes, quantities, and motions; for physicists today there are more intangible properties like electric charge. This excludes from fundamental ontology any qualitative properties, such as color, that are known to us only through our perceptual faculties. But once colors are excluded, how do we account for their manifest appearance as properties belonging to everyday objects? Either we say that our senses trick us into believing that external objects are colored, when colors do not in fact exist, or we try to find some account of colors that is compatible with a scientific ontology, locating them among material objects.
***
"Hardin’s case was that the most adequate account of color must be a neural one. In other words, colored objects are not part of extra-mental physical reality, but a construction or projection of the brain.
***
"Vision scientists Rainer Mausfeld, Reinhard Niederée, and K. Dieter Heyer write that, “the concept of human color vision involves both a subjective component, as it refers to a perceptual phenomenon and an objective one ... We take this subtle tension to be the essential ingredient of research on color perception.”
***
"In an influential textbook, perceptual psychologist Stephen E. Palmer writes that color is not reducible to visual experience or properties of objects or lights; rather, Palmer writes, “Color is more accurately understood as the result of complex interactions between physical light in the environment and our visual nervous systems.”
***
"It is common for physicists to explain the blue appearance of the sky as due to “Rayleigh scattering,” the fact that short wavelengths of visible light are scattered more by the Earth’s atmosphere than longer ones, so that diffuse blue light comes to us from all regions of the sky when the sun is high and cloudless. But we should not be tempted to say the blue of the sky is simply a property of the scattered light. There is no blueness unless the light interacts with perceivers like us, who have photoreceptors that respond differently to short versus long wavelengths of light.
"So, precisely speaking, the sky is not blue. We see it in a blue way.
***
"We’re used to thinking of conscious experience as something like a series of sounds and images rolling past on an inner movie screen. This is the conception of our mental life that the philosopher Alva Noë wants to break away from. In his 2009 book Out of Our Heads, Noe claims that consciousness is not confined to the brain but is somehow “in between” the mind and our ordinary physical surroundings, and that consciousness must be understood in terms of activities.5 By themselves these ideas are quite perplexing. But taking the example of visual experience, color adverbialism is a way to make sense of consciousness being “out of our heads.” According to adverbialism, color experience comes about because of our interaction with the world, and would not exist without this exposure to our surroundings. Our inner mental lives are dependent on this outer context."
Comment: We cannot get around the point that what we perceive from our brains is secondhand.
Is our vision of reality correct? neuroscience explains
by David Turell , Tuesday, August 27, 2019, 20:09 (1914 days ago) @ David Turell
Yes, but our brain makes up active guesses:
https://www.scientificamerican.com/article/the-neuroscience-of-reality/
"...Implicit in this story, however, is the assumption that a properly functioning perceptual system will render to our consciousness things precisely as they are.
"The deeper truth is that perception is never a direct window onto an objective reality. All our perceptions are active constructions, brain-based best guesses at the nature of a world that is forever obscured behind a sensory veil. Visual illusions are fractures in the Matrix, fleeting glimpses into this deeper truth.
***
"... we have known since Isaac Newton that colors do not exist out there in the world. Instead they are cooked up by the brain from mixtures of different wavelengths of colorless electromagnetic radiation. Colors are a clever trick that evolution has hit on to help the brain keep track of surfaces under changing lighting conditions.
***
"...these ideas have gained a new momentum through an influential collection of theories that turn on the idea that the brain is a kind of prediction machine and that perception of the world—and of the self within it—is a process of brain-based prediction about the causes of sensory signals.
***
"The central idea of predictive perception is that the brain is attempting to figure out what is out there in the world (or in here, in the body) by continually making and updating best guesses about the causes of its sensory inputs. It forms these best guesses by combining prior expectations or “beliefs” about the world, together with incoming sensory data, in a way that takes into account how reliable the sensory signals are. Scientists usually conceive of this process as a form of Bayesian inference, a framework that specifies how to update beliefs or best guesses with new data when both are laden with uncertainty.
"In theories of predictive perception, the brain approximates this kind of Bayesian inference by continually generating predictions about sensory signals and comparing these predictions with the sensory signals that arrive at the eyes and the ears (and the nose and the fingertips, and all the other sensory surfaces on the outside and inside of the body).
***
"To understand how dramatically this perspective shifts our intuitions about the neurological basis of perception, it is helpful to think in terms of bottom-up and top-down directions of signal flow in the brain. If we assume that perception is a direct window onto an external reality, then it is natural to think that the content of perception is carried by bottom-up signals—those that flow from the sensory surfaces inward. Top-down signals might contextualize or finesse what is perceived, but nothing more. Call this the “how things seem” view because it seems as if the world is revealing itself to us directly through our senses.
"The prediction machine scenario is very different. Here the heavy lifting of perception is performed by the top-down signals that convey perceptual predictions, with the bottom-up sensory flow serving only to calibrate these predictions, keeping them yoked, in some appropriate way, to their causes in the world. In this view, our perceptions come from the inside out just as much as, if not more than, from the outside in. Rather than being a passive registration of an external objective reality, perception emerges as a process of active construction—a controlled hallucination, as it has come to be known.
***
"A growing body of evidence supports the idea that perception is controlled hallucination, at least in its broad outlines.
***
"The central idea here is that perception is a process of active interpretation geared toward adaptive interaction with the world through the body rather than a recreation of the world within the mind. The contents of our perceptual worlds are controlled hallucinations, brain-based best guesses about the ultimately unknowable causes of sensory signals. And for most of us, most of the time, these controlled hallucinations are experienced as real."
Comment: The usual picture. Our brain accurately presents its predictions as to what reality really is. It works; we avoid the oncoming bus, and easily pick up our coffee cup.
Is our vision of reality correct? neuroscience explains
QUOTE: The contents of our perceptual worlds are controlled hallucinations, brain-based best guesses about the ultimately unknowable causes of sensory signals. And for most of us, most of the time, these controlled hallucinations are experienced as real."
DAVID: The usual picture. Our brain accurately presents its predictions as to what reality really is. It works; we avoid the oncoming bus, and easily pick up our coffee cup.
And the fact that it works makes nonsense of the claim that these are “hallucinations”. It’s the usual business of extending the subjectivity of perception to the sensational assumption that there is no such thing as objective reality. I just don’t buy it. If a million people step in front of the bus and feel the impact, that’s good enough proof for me that the bus exists. We may all see/hear/feel it differently, but that most emphatically does NOT mean it isn’t there – and that is the definition of an “hallucination”. Until these clever folk can prove the bus isn’t there, they should moderate their language!
Is our vision of reality correct? neuroscience explains
by David Turell , Wednesday, August 28, 2019, 14:12 (1913 days ago) @ dhw
QUOTE: The contents of our perceptual worlds are controlled hallucinations, brain-based best guesses about the ultimately unknowable causes of sensory signals. And for most of us, most of the time, these controlled hallucinations are experienced as real."
DAVID: The usual picture. Our brain accurately presents its predictions as to what reality really is. It works; we avoid the oncoming bus, and easily pick up our coffee cup.
dhw: And the fact that it works makes nonsense of the claim that these are “hallucinations”. It’s the usual business of extending the subjectivity of perception to the sensational assumption that there is no such thing as objective reality. I just don’t buy it. If a million people step in front of the bus and feel the impact, that’s good enough proof for me that the bus exists. We may all see/hear/feel it differently, but that most emphatically does NOT mean it isn’t there – and that is the definition of an “hallucination”. Until these clever folk can prove the bus isn’t there, they should moderate their language!
How else can wet brain show us true reality using travelling ions along living axons?