But, along with all the similarities, there must be differences. — Ludwig V

Certainly. Evolution is a huge, complex, interconnected web of living things developing the faculties that best served their survival. Many of those faculties are held in common by large numbers of species, in varying degrees, styles and intensities. Rational thinking is one survival tool that many animals use to varying degree, depth, breadth and efficiency. I don't say humans are not the smartest and most linguistic; only that they are not unique in the ability to solve problems, and that setting problems to solve is the only way that I know of to test this ability.

So there is legitimate enquiry to be had here, surely? — Ludwig V

It's been going on for a considerable time - I think we're coming up on a century of scientific inquiry into the subject.
What I object to is starting from a conclusion that should have been put to rest decades ago.

If the reasoning isn't correct, things can go very wrong. — Athena

Indeed. But 'correct' isn't in the definition of reasoning, nor is the soundness of the result. It's a process that can be carried out more or less effectively.

It is your opinion that I hold rational thinking as a human thing based on language that animals do not have because I want to exploit animals, is an opinion, not a fact. — Athena

I like that the definition begins with "correct reasoning". — Athena

'Incorrect', 'ill-informed', 'faulty', 'based on invalid premises and/or unfounded assumptions', 'inappropriate' and even 'fatally flawed' are descriptions that can be applied to:

Webster: 1. The use of reason; especially : the drawing of inferences or conclusions through the use of reason. 2. An instance of the use of reason : argument.

It is your opinion that I hold rational thinking as a human thing based on language that animals do not have because I want to exploit animals, is an opinion, not a fact. — Athena

I never claimed otherwise. And, in fact, the remark was not directed specifically at you - except inasmuch as you have been defending the human exclusivity position - but was an observation regarding a whole system of faulty/disingenuous human reasoning for the purpose of arriving at a desired conclusion.
Propaganda and advertising work in this same way: argument directed at a desired outcome. The purveyors of mis- and disinformation use a rational process to determine what kinds of falsehood their audience is most likely to believe and construct the most persuasive arguments to make their conclusions sound reasonable. Often, this involves altering the meaning of words and twisting familiar concepts, and may include denial of the audience's practical experience.

I like that the definition begins with "correct reasoning". — Athena

Why does 'reasoning' require a modifier? You can arrive at the wrong conclusion through a rational process, if you begin with false or incomplete information, if you start from an assumption that is later proven to be unfounded, if your initial purpose is to justify an act deemed wrong by others.

I get that humans want to be oh-so-special - not enough to be the most; we must be the only. Well, we have a number of claims to that exceptionality already. The reason - rational, but rarely acknowledged - we so desperately want to deny other species the faculty of reason is to justify our exploitation of them.

No, but what I'm saying is that "reasons" are not necessarily the result of conscious rational deliberation either. — ChatteringMonkey

Of course not. The reason why something is necessary precedes any consciousness recognizing the necessity, which precedes any deliberate action taken. Entities striving to survive are not acting at random; they're acting in response to a need: they have specific reasons for doing what they do, long before the development of a brain. Animals with brains recognize their needs, explore their environments and decide on actions intended to attain a specific end: find water, get food, erect shelter, seek safety.

Instincts are the original 'reasons'.. — ChatteringMonkey

Biological impulse is the original response to the environment and survival. Instinct develops much later , in increasingly complex organisms. Instinct and memory form habitual behaviours, then the even more complex brain adds curiosity and imagination to extrapolate situations beyond the present and consider alternative actions to reach the same goal.

And then eventually, socrates put forwards the notion that we should have conscious rational deliberation prior to the act as the golden standard.... rational thinking instead of instinct. — ChatteringMonkey

By which time, thousands of species had been doing it for 50 million years, without pontificating about it.

No animals don't already have a language. Language is next to culture, it has to be learned. — Athena

Yes, all social animals learn their language from their elders.

Now here is where the rest of the animal realm fails. It took us centuries but we now of an amazing comprehension of pi. — Athena

Not to mention all the means of mass extinction. The other animals fail most spectacularly by dying at our hands.

I dunno, that is the question right? And that question in turn depends on what you would consider "a reason". — ChatteringMonkey

Survival might be considered high on the list.

Does a chicken have a reason the scratch the ground when looking for food? — ChatteringMonkey

Yes: seeds scattered on the ground sometimes get covered by dirt. Having eaten all the visible seeds, the chicken scratches for any that were overlooked. Floors are artificial, beyond a chicken's repertoire of experience; she doesn't have sufficient information to be sure it won't yield to scratching.

So a lot of that behaviour seems to be instinctual. — ChatteringMonkey

That's where it begins. Drive - habit - instinct - adaptation - thought.
Some big brown slug didn't just hump itself out of the primordial swamp and grow into H. sapiens without reference to any other species. The process was long and gradual; the product exists on a scale and a spectrum.
A dog may not recognize its image in a mirror, but neither can a man pick the smell of his own urine out of a hundred other humans'. We self-identify differently and perceive differently, use similar faculties in different proportions, but the strategies and tactics of survival have to be coherent, directed and purposeful in order to succeed. By the time you're up the brain size of a great ape, most of its behaviour is controlled and directed - purposeful - even though we don't constantly think about what we're thinking and how we're thinking it (which would paralyze action and probably get us killed).

I think a lot of what we humans do is more or less the same, we do seem to do a lot of things without conscious rational deliberation, out of instinct. — ChatteringMonkey

We also have habits and instincts, yes. And many perfectly reasonable decisions that we don't dwell on, simply because they're learned reactions; considered appropriate to a familiar situation. Reason can't have been invented in response to being challenged: that's the wrong way around. Who was there to challenge an action prior to the concept of rational thought?

So, an anthropo-exclusive definition, based on argument, rather than discernment of cause and effect, problem solving and practical decision-making.
OK

The argument about chimpanzees and their ability to communicate is more complex than whether they learn a language or they can not. — Athena

They already have a language. The argument is over whether and how well they learn some version of a human language.

Our cats and dogs may be very good at communicating with us but wolves do not have that kind of relationship with humans. — Athena

Why would they want to? Wolves have very effective communication skills among themselves. Besides familial and social exchange of vocalizations, postures and gestures, they have quite a sophisticated method of organized hunting.

Individually, we are different in our ability to learn. More dramatic is the fact that baboons like to eat termites as much as chimps. They watch the chimps make tools to fish the termites, but they do not imitate the behavior, although they want the termites just as much as the chimps. I think that is equal to me wanting to understand math, and I just don't get it. — Athena

We're not only different in our capacity to learn, the speed at which we do it and in our ability to retain and recall information.
The baboon/chimp divide may be cultural. Just as humans disregard the habits of tribes with different world-views, it my be that apes disregard the habits of another species of ape. I suspect that if they saw a baboon of high social standing fishing for termites, they would be imitating him quite soon. (Experiment: have a trusted human teach a baboon to do it, then let him in among a troop of youngsters.)

Intuition is not rational thinking because there is no language involved. — Athena

What makes language the criterion for rational thought? Are there not math questions and diagrams on an IQ test? Does the crow deciding to use the short stick to retrieve the long stick to push the cheese near enough the bars so that he can reach it with the short stick require him to explain as he goes?

Intuition is rational thinking. You consider the information available, arrange it some configuration that makes sense, recognize what additional pieces of information you need for a solid, logical conclusion. But you don't have those extra pieces, so you look in memory for any items of information that fits with the pattern you have created. The conclusion you draw is not provable, but it's a working theory you can test. You may not be aware of the process, as it usually happens faster in your brain than you can translate into speech, but in retrospect, you should be able to describe how you arrived at the result.

Language of some kind is important for communication and useful labelling for memory organization, but that doesn't mean deaf-mute people can't solve problems rationally.

Post-hoc rationalisation probably was the original form of 'rational thinking', as social group-animals it was pretty important to justify/rationalize our actions. — ChatteringMonkey

Didn't people have a reason for their actions until somebody forced them to explain? We sometimes need to rationalize actions (decisions) that prove counter-productive, or that others disapprove, but how often does anyone justify preparing food, building a shelter or using a hammer to drive a nail into wood? The rationality of those actions is self-evident.

If having axes make a model flawed, then all models are flawed. It sounds like you're describing 3 disconnected points rather than a triangle with an area. — Brendan Golledge

It's very possible that all models are flawed; I haven't seen a large enough sample to judge. I'm saying there are not enough axes. Thus, the areas of overlap will still represent only primary coulours, rather than a spectrum. Actual social systems are far more complex and nuanced than that, and they change over time.

But my dim-witted friend did not take time to think through the problem. He put his hand through the gate and opened it from the outside. — Athena

He was thinking rationally: looking at a problem and finding a solution. He did it quickly, because it was very simple problem. (One might question the rational thought-process of the genius who designed the gate.) Reason is nothing more complicated than finding the connection between cause and effect, then projecting the if-then dimension. A causes B; therefore, if I affect the function of A, then B alters accordingly.
Reason and one's relative facility in reasoning has very little to do with verbal proficiency or fluency. Individuals with too deep a regard for what is said by those who speak authoritatively are some times fooled into believing what they're told rather than what they themselves are able to discern.

The 3 axes of the model are communism/equality, individualism/freedom, and authoritarianism/stability. — Brendan Golledge

Then the model is fatally flawed. Consider any real-life human being. Does he or she really only need or want one singular function from their society? Or in their life?
Those pairs of desiderata are not exclusive to the designated ideologies; in social relations, there is a great deal of overlap and concurrently existing conditions, and only one of the ideologies has a strong economic component in its name, whereas all systems are influenced, if not ruled, by their economic arrangement.
The model is invalid, as are the assumptions that proceed from defining factions according to that model.

Here is a crow using a stick to get food. Do you think this is rational? — Philosophim

How can you assess rational thought, except through problem-solving? Problems arise in nature all the time and animals need to solve them in order to survive and reproduce successfully. Whoever's ancestors were able to solve most of their problems inherited the most sophisticated brains. These are the cognitive front runners, AFAWK. However, living things also have mental attributes other than rational intelligence that vary greatly in range and style and function, which are far more difficult to quantify and compare.

There is no big fat black line between one species and its nearest kin - evolution is an n-dimensional continuum. We inherited our intelligence, communication skills, mimicking ability, empathy, instincts and emotional repertoire from previous iterations of great ape.

Do animals have rational thinking? — Athena

Of course.

Do animals have communication skills? — Athena

Of course.

Is intuitive thinking rational or maybe something better? — Athena

Intuition is a shortcut to an answer in the absence of sufficient evidence to draw a logical conclusion. It is based on recalled experience and knowledge.

The problem lies in the application and logistics. — I like sushi

Is there enough air for everyone to breathe? Is there enough clean water for everyone to drink and wash in? Is there enough food for everyone to be nourished? Is there enough shelter for everyone to be warm and dry? I don't see the problem -- except that a few people take a hundred or thousand or million times as much as they need, piss in the pool, and leave the other people to fight over whatever's left.

You are for "smashing eggs" then? — I like sushi

I'm not for or against it. I haven't been and will not be instrumental in the events; I have not been and will not be consulted in the matter. I see people stacking eggs on top of eggs on top of eggs and I predict that the stacks will topple over and the eggs will break.

The question is still left open about how you know what everyone needs? — I like sushi

What would you die without? So would everyone else. What would you die from? So would everyone else. Supply the first group of elements and eliminate the second. Maslow proposed a good starting point.

You oppose 'social engineering,' as do I to a degree, yet seem to hold some form of it in your head as you have a theory (a vision to work toward) — I like sushi

A hoped-for destination, yes. So you have a criterion for judging each proposed step - is this getting us closer to the desired outcome or veering off in some other direction? Each legislation, each reform, each legal decision, each commercial transaction, each building construction, each technological innovation moves us toward or away from peace, health and comfort.

I think it is safe to say we are both opposed to "smashing eggs to make an omelet." — I like sushi

It's not that. I haven't called for revolution or a philosopher-king with unlimited power. The way things stand, I'd rather see a supercomputer in charge than the motley collection of humans who run things now. But my main contention is that the way things are can't keep standing very much longer. Tipping points loom hither and yon.
Fifty years ago, we were on the right track to social improvement, but largely wrong on the technology and infrastructure. The mechanics have continued headlong in the wrong direction, while the social improvement has been halted or reversed.
More people are miserable and going crazier than ever, and more people are under greater threat. i don't see a mechanism whereby this trend can correct itself. I see it heading for self-destruction.

Afterward, there likely to be survivors. The ones that don't eat one another will have to figure out how to survive in the ruins, in a hostile climate. Utopia will have a long, long wait, but at least it has a tiny glimmer of hope.

How can you say how your vision works for everyone? — I like sushi

By the fact that it's not my vision alone: it's a distillation of historical information about social arrangements that were stable and equitable, of 2000 years of European folk tales and songs and of the yearning of utopian literature through the centuries.

Is that not like stating you know what everyone want. — I like sushi

There you again, confusing needs and wants. We all need the same things, adjusted for size and level of activity, and we don't have to know in advance what everyone wants. People are capable of expressing their desires and aspirations; they're capable of reciprocity and of co-operating on community projects. All they require from their society is freedom to pursue those aspirations - so long as they don't harm the environment or restrict other people's freedom.

I am guessing not, but you can probably see how easily this can be misconstrued. — I like sushi

Some people make a strenuous and sustained effort to misconstrue and contend, I suppose because that's what they want. Some people seek clarity and consensus, because that's what they want. The world is big enough for both kinds of personality and many more besides.

It is just a fantasy, yes? — I like sushi

It's a theory. You can't get there from here without climbing over a whole lot of rubble.

t seems you are more or less Piecemeal then rather than having any explicit idea of what utopia would look like let alone laying out any particular roadmap for it. — I like sushi

Knowing what a place looks like and having a roadmap to it are separate ideas. I know what it looks like to me; i know how it works for everyone. I know you can't get there from here by pieces or meals or revolutions or engineering.

I believe you are advocating for Piecemeal rather than Utopian Engineering? — I like sushi

I don't advocate any kind of social engineering. I hope for social evolution.
You can read Utopia as 'No Place' and assume that means either that it can never be, or that it is not yet. Or you can read it as 'Good Place' and imagine what a good place would look like.
I see nothing fatalistic about either.
There is no inevitability about making a good society. It's not even probable. It's a long-shot at best. I just don't believe it's impossible.

I am closer to Auden than Eliot as a life partner. — Paine

Can't say I feel 'close' to Eliot. It's admiration, rather than kinship. At heart, I'm with the Romantics - Shelly, Coleridge, Wordsworth, Tennyson, then Dickinson, Auden, Housman and I'd have to add Frost and LePan as later editions. I appreciate many modern poets, but that's more cerebral than emotional.

I mean, who's going to match

Break, break, break,
On thy cold gray stones, O Sea!
And I would that my tongue could utter
The thoughts that arise in me.

O, well for the fisherman’s boy,
That he shouts with his sister at play!
O, well for the sailor lad,
That he sings in his boat on the bay!

And the stately ships go on
To their haven under the hill;
But O for the touch of a vanish’d hand,
And the sound of a voice that is still!

Break, break, break
At the foot of thy crags, O Sea!
But the tender grace of a day that is dead
Will never come back to me.

I've heard that Richard Burton learned to project by standing on a cliff and reciting it to the ocean.

My Gr 13 English teacher arranged for some of us to attend a small theater performance in Toronto. Low stage, no orchestra pit, actors making their entrances and exits down the aisles - intimate. Damn thing blew me away, especially the chorus! I've read it several times since, plus all things Eliot. The film version was okay, but nothing like being there.

Do you try to memorise poems? — Amity

Not anymore. If I'm introduced to a new person now, another name falls through a lacuna in my brain - I just hope it's a dead pop singer's, not my next-door neighbour's. But I still know If and Invictus pretty well, most of the Walrus and the Carpenter and scraps of The Highwayman (because my brother would strut about declaiming it endlessly when he was in Grade 6) tatters of Shakespeare's soliloquies and for no reason i can understand, fragments of Murder in the Cathedral.

I don't know if this is the song you mean but I'll play it anyway. Lean back and listen or sing along... :cool: — Amity

That's the one. I like old songs - you know, from when they had discernible melodies and intelligible lyrics. I caught from my mother the habit of singing while I do mundane chores, and so from years of repetition, I have a much bigger store of song lyrics than poems.

The two poems on bulletin board, lest I forget, are:

Nothing Gold Can Stay by Robert Frost

Nature’s first green is gold,
Her hardest hue to hold.
Her early leaf’s a flower;
But only so an hour.
Then leaf subsides to leaf.
So Eden sank to grief,
So dawn goes down to day.
Nothing gold can stay.

and Yeats' Second Coming, which I wouldn't even try to memorize.

Those obviously resonate with me. At the rate the rental on this body is increasing, I won't be able to stay very much longer. It's a time to appreciate what I've had* and come to term with all that's left undone.
*Not a poem; a song. The iconic Louis and Ella.

I have no problem with it being in a corner I visit regularly, rather than being buries in Philosophy of Art, which can get ponderous and pretentious at times.

Here's one I like:

"The Full Heart" by Robert Nichols (1893-1944)

Alone on the shore in the pause of the night-time
I stand and I hear the long wind blow light;
I view the constellations quietly, quietly burning;
I hear the wave fall in the hush of the night.

Long after I am dead, ended this bitter journey,
Many another whose heart holds no light
Shall your solemn sweetness hush, awe and comfort,
O my companions, Wind, Waters, Stars, and Night.

I don't think its possible to call someone an asshole from their public output, unless its criminal/socially criminal. — AmadeusD

It's possible. I've proved this on several occasions. Their public output is how they want to be known by other people. His public output is toxic assholity. I'm just fulfilling his express desire by expressing the reaction he's worked so hard to elicit.

Far from it. Just one eg... He's an incredibly effective therapist and his general self-help stuff is honestly really, really really good for our times, and for hte crisis he's trying to address in mostly men. — AmadeusD

I'm not privy to any of that. I hope his god takes it into account.

Wondered if you wanted the humanizing aspect. — AmadeusD

Background; struggle with and recovery from substance abuse; helping other addicts - that sort of thing? I know nothing of his private life, hobbies or charities. It would take a great deal of benevolence to make up for the bilge he gets paid for spewing out into the public discourse.

Why people care about 'agreeing' like it is something to be valued I have no idea. — I like sushi

It tends to keep the homicide stats down. Opposing 'views' can be hard on a society. Eg. "There is no such thing as witchcraft" vs "Thou shalt not suffer a witch to live."

Seen some of his videos, gods help me!

Or is this just sort of yelling into the ether — AmadeusD

Aren't we all? Isn't that the purpose of this present endeavour?

Off-topic aside: Jordan Peterson is a bigger AH than Elon Musk.

And I'm tired of repeating my own thoughts. I did look at your philosopher, and much prefer John Rawls.
We are not likely ever to agree on this subject, so why waste any more time?

https://equalitytrust.org.uk/the-spirit-level/
http://www.ajic.mb.ca/volumel/chapter2.html
https://jerichowriters.com/utopian-fiction/
https://www.ic.org/?srsltid=AfmBOopnTJ7l767Y98HDi5oF_NonWVLBuSCE0VPqxOn6zbplLCB0-kTY
Just some other people's thoughts on what a good society is.

You brought it up on that particular point and I have no idea why. — I like sushi

Show me. In context, if at all possible.

I mentioned that to achieve utopia could involve something along those lines or some other means of levelling the playing field. — I like sushi

Could - not must. OK

Instances of these kinds of actions were obvious enough in the 20th century. — I like sushi

Instances of ideological conflict were obvious. To what extent they were utopian, or even sincere, is questionable.

I am stating that aiming for a utopian ideal is wrong and you are saying it is right. — I like sushi

Yup. Fundamental difference of opinion.

Aiming for a utopian ideal would involve having a target to aim for, not merely the incremental pursuit of some better world. — I like sushi

Yup. "some better world" is too vague for my taste. Better than what? Better for whom? Better in what ways?

arguing about the present situation helps your position how? — I like sushi

It wouldn't, had I done so.

We can see currently that rich and poor and differences in status or cultures does cause confliction. — I like sushi

Yup. That has to be one of the first problems needs solving - assuming there is time to solve problems before the whole house of cards collapses. Is it a conflict between two individuals, or between two equal sized groups of persons? Or between a very few people and an enormous number? I wonder how that would play out, hand-to-hand, without a mercenary army on one side.

What I am saying is that as population grow and conflicts of interest appear then there is growing social strain - this should be apparent enough from what I have previously written surely? — I like sushi

What's causing the growing strain in your scenario? Differences among persons, disparity of resource distribution, ideologies or goading by demagogues with their own agenda?

our reference to me bringing up genocide and such, or some other means of leveling the playing field, was in regards to feasible pathways to a utopian ideal. — I like sushi

There is nothing feasible about means that would destroy the ends they aim for.

We can see currently that rich and poor and differences in status or cultures does cause confliction. you can se this literally anywhere on the planet. When there is a problem with resources or large cultural disparities - basically conflicts of interest - then things can turn nasty fairly quickly. This is not new news to anyone. Understand? — I like sushi

Yes, and that's pretty much the point. Up front, I said that a utopian vision depends on eliminating wealth disparity, uneven distribution of resources and ideological indoctrination. You seem to assume these things are inevitable and unavoidable. I believe they will crumble with the current world order.

there would still be matters of religion, pride in the group, politics, traditions and of course individual abilities. — I like sushi

As I've said several times already: You can't get there from here, except with many, many baby steps (some of them backward). Nationalism and religion have to go. Politics has to change dramatically. Tradition is okay, in the form of parades and festivals, as long as it doesn't try dictate decisions for the future.

The reason is the utopian ideal springs from equality and true equality can only be achieved if everyone is basically the same - which we are not. — I like sushi

We are basically the same. Two arms, two legs, one head, opposable thumbs, warm blood, insufficient body-hair, big brain, needs air, water, food, shelter, mating opportunities, companionship, something to think about, something to do, respect of peers...
How basic is your basic? How short do you think we have to mow human potential to make people capable of tolerating one another?

If the head of state in your country decided to reveal an incremental roadmap towards some vision of utopia would you back them over someone looking to make some improvements to the existing scheme without any idealistic goal? — I like sushi

In general, I would prefer a leader with vision. In particular, I would want to know what improvements they proposed to make.

I am not interested in some combative debate where one of us pumps the air with our fists at the end taking delight is 'winning an argument' rather than exploring ideas. — I like sushi

All right. I won't do that.
I believe - or try very hard to believe - that you (and Nozick) are wrong about human nature.

I find a difference between saying 'personal identity exists' and saying 'we experience the life of being a person.' — Paine

That's because "exist" is such a difficult word to agree on. I consider something that exists to be tangible, measurable; real. Concepts do not exist - that is, they have no material reality. They are products of the imagination and of language - which means, open to a great range of interpretations.

Killing? Conflict does not mean 'killing'. — I like sushi

I didn't drag genocide into this discussion.

There would be disharmony of a sort.

There would be all kinds of local disharmonies. So what? Any functioning society can institute a mechanism whereby people can resolve their arguments and restore harmony to the community. It's certainly not an existential problem.

Diversity does necessarily involve conflictions. — I like sushi

Then why is every society on Earth not tearing itself apart over the existence of all those fat and thin, dark and fair, tall and short, clever and dull, brisk and relaxed men, women and others, some of whom like jazz while some prefer rock, some of whom eat rice while some like potatoes?

Believe it or not I am optimistic for humanity — I like sushi

And yet consider us so short-sighted and intolerant that we can't live in a society with people who are unlike us, or share resources among occupations.

There can be no arguments to prove or disprove personal identity. — Thales

You don't need to argue about it. You only need to experience it. And if you doubt other people's ability to identify you, try committing a crime and claiming that, since it happened last month, some other guy did it. It's not just a rule; its our modus operandi.

Is anything I have been saying made any sense whether you agree or not? — I like sushi

It all makes sense from a certain perspective, based on a certain set of assumptions. You may be right; humanity may be altogether irredeemable. I was speculating based on a different POV.

Did you look at the book by Nozick btw? It is an interesting read. — I like sushi

I will try.

No? This is not about me. Kill? That is a bizarre interpretation of what I outlined. — I like sushi

Well, if you're not inclined to kill people for being different, why assume everyone else is? Why assume diversity equals conflict? I have lived peaceably among enough people who are different from me and different from one another not to believe that.

Utopia cannot be brought about under any state of affairs without causing mass harm, genocide, homicide or some means of 'levelling the playing field'. — I like sushi

It cannot be brought about in one fell swoop. I have several times stipulated as much: the good society is an ideal to aspire to and work toward, not a state that can be created wholesale.
We have too much deeply entrenched, deeply invested disparity of power and means for any reasonable distribution of the necessities. We have too many ideologies and creeds that deliberately promote strife. And we have too large a population for the planet to sustain in comfort.

The field will level itself as the result of our previous bad decisions, harmful intentions, wrong directions.
Afterward, the survivors will have to do something. They can make all the same mistakes and commit all the same atrocities again, or they can set off in a new direction. In my theory, it can be a better direction.

So you define a utopian society as being one that keeps people alive rather than one that also satisfies people's wants? — I like sushi

No. I defined it as a society that satisfies peoples needs and provides opportunity for people to satisfy their own and one another's wants. This should not be such a difficult concept, since all functional societies have a mandate to do this. They just don't do it very well.

If we all envisage different things they also contradict each other. — I like sushi

I say that if we don't have to fight over the necessities, we are better able to choose and create the luxuries. You say the luxuries must come with the package. You demand more than is possible and then argue that it's not possible.
A place where there is nothing left to try and nothing left to desire is not Utopia - it's death.
If you prefer fish and I prefer pasta, we don't need to fight over either. All we need are some very basic laws regarding personal liberty and responsibility. (Not the million contentious laws we have been trying to uphold and knock down in civilized countries.)

Height, sex, weight, intelligence, personal preferences, tastes, fortitude, vulnerability, sociability, etc.,. — I like sushi

And all these differences grate on you? You want to kill all those 'other' people? Me, I find uniformity rather a bore.

Because they would not be able to communicate and negotiate well enough leaving many on the fringes of society. — I like sushi

And yet they did. And we do, with people around the whole globe. (We're even trying to communicate with other planets.) Even now, with all the strife over territory and resources and population movement. So why would we suddenly stop being able to communicate if the strife ended and there was nothing major to negotiate? I don't see the logic of people being on the fringes (whatever fringes are when the needs of all are satisfied) because they're less able to communicate with people they don't choose for company than the ones they do choose.
In fact, I don't see the logic of variety as an obstacle to social cohesion.

I do not feel that you appreciate the danger of opting for some utopian scheme rather than just trying to improve the current state. — I like sushi

I'm not opting for it. The option was never open to me. I'm saying it's theoretically possible. And also that having a destination in mind is useful in choosing one's path; that a clear vision of how society should work is helpful in making incremental improvements. ....

.... in theory. In actuality, we're just hanging on the precipice of extinction by our fingernails. Survival is still possible, but it's not going to be any picnic.

Satisfying people's wants and needs is part of the utopian ideal. — I like sushi

Needs, yes. Wants are individual; all the society can or should do is provide the opportunity for people to satisfy their own wants.

Separate communities in a utopian society cannot stably coexist because of this limitation. — I like sushi

Why the hell not? Native tribes on various continents managed quite well to remain separate, and yet trade and party and look for marriage partners.

Yes, but people still differ. the larger the population the prominent differences become as they grate harder on each other. — I like sushi

Why should they? What - aside from cultural indoctrination - are these prominent differences? Even with cultural diversity, people can get along just fine. Toronto used to enjoy a thriving Chinatown, a Jewish district and market, the Italian strip, the Ukrainian and Hungarian, Greek and Caribbean, Irish and Portuguese neighbourhoods. Yonge Street got pretty raucous during FIFA playoffs. St. Patrick's day was a lot of fun, and so was Caribana. If there is no scarcity of resources or ethnic dominance to compete for, and nobody inciting one group of people against another, what have they to grate about? Anyone is free to associate with those they find pleasant company and avoid people they don't like.

With Dunbar's Number we know that societal ties breakdown over a certain population threshold. — I like sushi

And yet, cities and nations consist of many million citizens, and don't break out in civil war. Why does everyone need a direct tie to everyone else? How long has the place where you currentIy reside existed? If you can tolerate the presence of strangers there, in spite of whatever inequalities, injustices and annoyances exist there right now, why could you not accept them in a fair and benevolent society?

Of course a utopian or optimal society cannot be brought about in our present state of affairs. And maybe too many of us are too crazy to want it. Nevertheless, I believe it to be a theoretical possibility.

That was an example of how everyone would be happy. the simple truth is people are different and as long as they are different utopia is impossible - hence clones or forcing conformity. — I like sushi

Why would people drag 'happiness' into social organization? Whether a person is happy or sad, grumpy or cheerful, bluff or dour, sociable or reclusive is entire personal. You can have personalities, proclivities, preferences and moods under any political system. What a good, or optimal or utopian society does is prevent people damaging, oppressing and exploiting one another; provide a means of settling disagreements, make sure every child is cared-for, nourished and educated, take care of the sick, injured and feeble, then allow its members to pursue their own path to happiness.
(Incidentally, the snapshot of happiness my mind invariably throws up is of three men fixing a tractor. There are other pictures, like a 10-year-old bringing home an A on a complicated science project and a young mother showing off her baby. Assuming physical and mental health, I don't see why the things and situations that make us happy need to be incompatible.)

The push and pull between individualism and state authority is the biggest hurdle for utopian ideals. — I like sushi

Yes. It's an obstacle, just as long as egalitarian, democratic means of participation in "the state authority" is not available to all citizens.

In no way shape or form are humans alike enough to inhabit - en masse - a singular society. — I like sushi

What is a singular society? We currently have a number of countries where large numbers of individual have been able work out a system that accommodates most, and that could include all but the most aggressive and greediest - since they're the ones hogging the resources.
This is one basic assumption about humans on which you and I disagree. All living things have needs in common; all members of a phylum have even more in common; all members of a family have even more in common; all members of a species are more like one another than they are like any other species. The natural (not culturally induced) differences in taste, ambition and temperament are so superficial that any well managed social group (such as a labour union, sports team, men's benevolent association, congregation, knitting circle or community garden) can accommodate them.

If they choose to leave then it is clearly not a utopian society. — I like sushi

Why can a good society not consist of many communities? All the bad ones and okay ones do.

Okay. You have a certain set of assumptions about humans. Mine are slightly different, and my idea of a good society - one that aspires to incremental improvement in the life of every individual - certainly doesn't include brainwashing. Nor is there any reason for a good society to operate on a single model. If you're not happy and you're free to leave, I suppose there would have to be an alternative community to join that's closer to your ideal. There is no reason a number of communities with different organization and living arrangements should not co-exist.
Of course, as previously noted, this presupposes a considerable reduction in population. That's not something I advocate - that's something I predict.

It is the idea that someone believes they know what the best is that irks me. — I like sushi

Yes, I get that. It's like someone believing they know what's 'optimal', but they don't specify any metrics or benchmarks. The ideal, like the optimal, is just a big picture that we try to colour in, one tile at a time, coherently, instead of throwing random pigments at the bits we don't like at a given moment.
I think we have a similar vision, couched in different terms.