The title is from a blog post by Brian Leiter. Leiter links to an article in the LA Review of books: Imitation and Extinction: The Case Against Reality. The article is written by Donald Hoffman.
We have discussed the general topic before, in several threads. So maybe this is a good time to revisit the topic.
Hoffman asks: “I see a green pear. Does the shape and color that I experience match the true shape and color of the real pear?”
My take is that there is no such thing as the “true shape and color of the pear.”
It is a common presumption, that there is an external standard of truth. Here, I mean “external to humans”. Truth is presumed to come from somewhere else. And our perceptual systems evolved to present us with what is true.
As I see it, this is backwards. Yes, our perceptions are mostly true. But this is not because perception is based on truth. Rather, it is because our human ideas of truth are based on what we perceive.
Open for discussion.
I said I wasn’t sure about that. Especially the phrase “causes us”.
Why would we invoke the concept of ‘triangle’ if not for the fact that we were (mis)perceiving one?
keiths,
Where is that happening and how is it happening?
In the visual system, and the illusory contours are being inferred from the partial contours presented in the figure.
But again, why would we invoke the concept of ‘triangle’ if not for the fact that we were (mis)perceiving one?
That’s no answer. 😉
Joining up the dots has evolutionary advantage.
Alan,
Sure, which is precisely why we misperceive the triangle. The contours aren’t really there, but they are “filled in” by our visual systems. We don’t invoke the concept of triangle until we misperceive one by this mechanism.
Well, that’s certainly what it feels like to me. How does it happen, though? What’s going on in our brain?
There’s a ton of literature on the topic. Google “illusory contours”.
Haha, “you are uttering arrant nonsense, but you are in good company doing so”.
No worries, walto. I am not easily offended, and quite enjoying this conversation.
keiths,
Lots of examples, yes. My question is where and how does our brain create the illusion.
ETA
It’s clear the dot joining happens in brain tissue and activity It’s reasonable to surmise the modelling of shapes from the incomplete visual information has an evolutionary advantage (spotting predators etc). How does the brain do this and how w is it inherited?
Well, you were using animal behaviour to argue that ants and birds don’t think of chairs the way we do. I simply tried to use the very same example to demonstrate that certain perceptions about that chair are shared. At the very least, it should be clear they perceive [something] that must be circumnavigated; birds nor ants bump into stuff. I am pretty surprised that you resist such a basic argument.
As an aside: It is clear that, in true Charlie-style, you underestimate what animals are capable of. Ants have a superior sense of smell, so I am pretty certain they can tell the difference when they cross over from the floor to the chair (though I agree they may not perceive the entire chair as a whole). Perhaps you should study them for a while?
Corneel,
Regarding watching ants, you don’t need to build a farm. Where I live they are ubiquitous. And their activity is fascinating to watch. When there is a scent trail and two-way traffic, there seem to be many instances of bumping into each other.
I am willing to bet that’s on purpose: ants communicate by exchanging pheromones.
Corneel,
Absolutely. After bumbling into another ant there is feeler contact almost like a passport check and both ants move on satisfied.
I am not sure what you are referring to by “this”.
If it was the salmon example, we can conclude that fMRIs would not be a good tool to determine whether a fish was fresh.
Also that fMRI statistical modelling and its applications need work and that, as usual, unduplicated studies should be taken with a grain of teriyaki sauce.
Alan:
Far more than just examples.
Then Google “illusory contours” and explore the results. Don’t give up so easily.
An illusory surface:
Dots and joining them up are just figments of your imagination, so we are told.
Well, on the basis that there are a thousand different philosophical viewpoints, doesn’t that mean that all but one of them is uttering nonsense?
Stereogram version of Kanisza figure. Note a) that the illusory contours only appear in stereo, and b) how the illusory contours “overpower” the continuity of the vertical lines.
ETA: If I work at it, I can get the illusory contours to appear even when not in stereo, but the effect is weak.
Well the triangle I see is not there in external reality even though I see it quite clearly. Therefore, either the “reality” or the idea of the reality exists in my brain. I’m curious as to how that happens. I’m already convinced why the phenomenon exists and has to do with niche/organism relationship, adaptation and selection. But that is not an answer to what is going on at the level of brain function and brain cells.
The paper you referred to.
Indeed
🙂
🙂
But first can you say whether you have already come across an explanation of the phenomenon that indicates how such illusions are created at the level of neurones?
That would save time, perhaps.
The ant’s personal purpose? How can ants represent purposes and thereby act to achieve them?
Fitness’s purpose as captured in genetically-fixed behavior would make better sense.
But then someone would accuse me of reifying something or some not-thing, I suppose.
I agree with that much. But it does not follow that they see it as separate from the environment.
Perhaps they see it as separate from what you take to be the environment. But is it separate from what they take to be the environment?
Who would do that? But I agree that purpose in ants is adaptive and innate.
What kind of drawing would not be an illusion?
Why would they need to represent purposes?
Does a newborn child need to represent something in order to breath?
Breathing is another one for nature via fitness.
If the entity is not representing its purposes, then you are in your description of its behavior. That would be a Dentettian intentional stance or design stance, I’d say, although I would not have expected you to take that sort of position.
ETA: I think it is important that the context I was quoting used the phrase “on purpose”. I think the “on” implies the ant’s purpose.
I actually attempted to characterize purpose in an old series of posts on my blog.
A system can be said to have a purpose or goal if it is measuring how well it has achieved that goal and is adjusting its behavior in accordance with that measurement.
So a homeostatic system does have a purpose of remaining in stasis. But water does not have a purpose of flowing downhill.
And, no, I don’t see this as equivalent to Dennett’s intentional stance.
Since I neglected formal training in philosophy, I lack the vocabulary to express what I’m thinking.
But it seems to me that there are at least two unrelated phenomena being conflated.
Certain black and white objects, such as a Benham top, induce the perception of color. Color is a perception without form or dimension. It is not an object and does not need to be associated with an object.
Triangles, spheres, etc, necessarily have form, but are not objects. When we see an image and label it a triangle, we are not seeing a triangle, but are perceiving a form we have learned to associate with a word.
The stimulus need not be complete, or whole, or particularly representational. Brains and eyes leap to completion. We see objects in clouds and ink blots.
These are not illusions. They are examples of something very useful being done by brains. The rapid association of incomplete stimuli with the need to react. Mistakes happen. Evolution and learning tweak probabilities.
Forms such as triangles are not magical. Their distinction is in the simplicity of their definition. Lizards have a definable form, but one cannot define that form in a few words.
In both cases, however, we can have abstract representations. Picasso might be able to represent a lizard in as few lines as we use to represent a triangle. Neither case is an illusion.
How can you measure that way without a standard being represented against which success is judged/adjusted?
See the ETA to my post that you replied to.
I see the issue as about what it means to say an entity has its own purposes. I think that has to involve flexible representation of its purposes as some future state of the entity and its environment. The entity also has to be capable of acting to achieve the represented state (representing without acting would not be evolutionarily viable).
That represent/act mechanism is supported by evolution since it would enhance ability to maintain homeostasis (ie life) as well as to propagate the organism’s genes. That’s where I see homeostasis entering the picture.
ETA: I’ve been assuming that purposes must be represented neurally, at least for biological organisms here on earth. But maybe you could make an argument that purposes can be represented by hormonal concentrations, eg hunger by the system described here:
https://www.dummies.com/health/nutrition/how-your-brain-signals-your-bodys-need-for-food/
Why do you say it exists? This thread is all about things not existing, and yet you are convinced it exists?
Good point. I’m tempted to agree that “illusion” is not the right word in this context.
phoodoo,
See my reply to petrushka.
KN’s guy, Anil Seth, says conscious perception is an hallucination, not an illusion.
(He’s a PP supporter so I think he is right too.)
Can hallucinations capture some aspect of causal structure of reality? I argue that the IBE of successful action in novel environments is that perception is accurate because it latches onto reality. Most of the time, at least. Sometimes we hallucinate illusions, but those can be argued to be unavoidable faults of the overall success of the perception that evolution has produced.
But of course you can deny that that IBE is correct. Although how you can type accurately into the edit box of WordPress when you express that denial, well that is a bit of a mystery. Which would be fine for Alan, of course.
Thought some here might enjoy this:
https://getpocket.com/explore/item/open-minded-people-have-a-different-visual-perception-of-reality?utm_source=pocket-newtab
Yes, I think the positivists would hold that it’s all been pretty much nonsense and that the propositions that are actually true or false in the vicinity aren’t terribly interesting from a philosophical point of view.
BruceS,
Could I suggest that initial use of an acronym is anotated with the expanded phrase. TIA (thanks in advance). ,😜
Just want to reiterate that few people agree with the Tractarian/positivist view of this matter these days. For my own part, I don’t think metaphysical claims are meaningless, and am actually partial to claims that may be considered in some sense “mystical.” It seems to me that they may convey important information whether or not they are empirically confirmable.
(Unsurprisingly) I’d follow Hall in calling the dispute between you and Neil “categorial.” That suggests that only philosophical means can be used to adjudge the matter and that there can’t be any dispositive “proofs.” One has to consider the whole foreign conceptual scheme from one’s own vantage to the extent that’s possible and consider its usefulness, coherence, fecundity, etc. But we can’t just ditch our own categories and take up the matter from “God’s point of view.” That’s the “categorio-centric predicament.”
(Pick up my book for more on this.)
Alan Fox,
I don’t see how that answers the question at all. You are saying that a phenomenon “exists” in your brain, and the brain of others, that was formed through evolution. So are you suggesting that what your experience actually exists?
Does the phenomenon of love really exist? What about the phenomenon of faith? And they exist simply because they confer a fitness advantage to their recipient?
And the same can be said about the belief in science right? In math? If you believe in math, it gives you a reproductive advantage. That is all we can really say about its validity.
It doesn’t.
Thanks for the link!
…Though the research suggests that personality affects the way we filter conscious experience, it’s not clear exactly how this process works.
…The mechanics behind how personality is formed—and the effects it has—are still unknown.
In trying to make sense of the image it is I myself and my expectations who has to takes responsibility for having the illusion of an opaque white triangle in my field of vision. The person who created the image is responsible for it to be available to view. You are responsible for copying it so as to make it available for me to observe.
In The French Revolution by Thomas Carlyle, he writes:
The well known video of the person in the gorilla suit walking through the middle of a basketball game is worth a thought. All the spectators will be getting images of the same scene arriving at their retinas. And so their optic nerves will be likewise transferring very similar signals to their brains. So where does the difference lie between those who are aware of the gorilla and those who are oblivious to it?
Neither the physical eye nor the physical brain can be said to have illusions. This is an illusion on the individual as a sentient being. Neither the eyes nor the nervous system can be isolated from this being with regard to who or what is having the illusion.
We need not have the full compliments of a triangle before our senses in order to assign the concept ‘triangle’ to the entity perceived. Just three points of light (Deneb, Altair, and Vega) are enough to be designated the summer triangle.
You have provided a two dimensional image. We try to make sense of the image according to the three dimensional reality of our everyday world. The image gives the impression of a white triangular object partially obscuring a black edged triangular object placed behind it. It is not my eyes nor my brain that are trying to make sense of the image, it is myself trying to make sense of it using my eyes and brain.
I’m addressing the phenomenon of dot-joining keiths has posted on above. There’s no doubt we (at least nobody has said they don’t) see a triangle that isn’t there. Our brain creates it.
I see the triangle. My experience is real. The process, whatever that is, by which the brain produces the triangle seems to be widely if not universally shared by all humans. That suggests it’s adaptive and heritable. The process is a mystery, however.
I think I could make a case for that, yes.
The main thing about science is it works. And math works as a tool of science.
Exactly! Any sentient being is limited in understanding. It cannot understand anything as complex as itself.
That’s all an eye can give to the brain. There is additional information from binocular vision for those lucky enough still to have it.
Here’s my problem.