When it comes to human society, two extremes readily present themselves, namely that of a utopia and a dystopia. The former being a human society where its individual members have reached near-complete harmony and levels of cooperation. The latter is the exact opposite, with everyone basically having to fend for themselves, against practically everybody else.
A dystopia also sees oppression, slavery, escaping from reality through drug and other habits, and many other types of unpleasantness. There is no shred of consideration for the well-being of others, let alone room for compassion without this being brutally exploited and punished.
I leave it as an exercise here which of these two scenarios is the more realistic model for human society.
If one has to visualise an individual's mind, it can be done so as a collection of colours, each representing different aspects of the mind and brain. From the effects of the physical structure of sections of the brain, to specific neurotransmitter levels, to memories. Each contributes to this mosaic.
What affects this mosaic are all inputs, with each form of input visualised as a colour as well. Harmonious combinations reinforce the mind's colour, while disharmonious combinations lead to the rejection of the input. In short, this means that a mind will be more susceptible to certain types of inputs than others. It also means that strong stimulation using harmonious inputs can overwhelm the mind.
Such inputs can thereby range from natural sensations, such as a breeze, or the sound of birds, to the involved communications of human society. It is the latter which is the most interesting here. Yet some individuals already show strong differences in their susceptibility to such natural sensations, with some preferring it strongly, while others reject it outright. Here the levels of harmony with the mind mosaic can already be observed.
When it comes to human communication, the biggest difference is that these can carry ideas and concepts. This level of abstraction goes far beyond the consideration of whether a certain sensation is harmonious or not. It is also the foundation on which human society is built, as it fosters and enables cooperation on otherwise inconceivable levels.
Yet consider what happens when one takes a large number of minds, each with their own distinct mosaic and observes their communication. Some communications may be harmonious, while others will not be. Each mosaic is affected differently, with colours growing and shifting. Similar (harmonious) minds will group together, while disharmonious minds will distance themselves.
The realisation hereby is that the starting state for these mosaics are generally fixed at birth, with changes to the brain after this following this existing state, with only traumatic events capable of large-scale, permanent changes. What this basically means is that after the first formative years, the mind's mosaic is practically set in stone. The only thing which will then change are the type of ideas held by the mind.
Ideas are interesting. They are often simple things such as 'it is bad to kill a person', or 'one should not steal from others', while they can also be infinitely more complex. In order for a mind to accept such an idea, it has to be harmonious. This means that its visualised colours have to be correct, or the idea will be fully or partially rejected.
The astute reader may at this point have realised that there has been no mentioning of either intelligence or reasoning in the preceding discussion. The reason for this is that the above operates on a level below what can be considered intelligence, despite it being the primary operating modus for the average individual.
An intelligence can observe ideas, reflect on them and come to a reasonable conclusion based on available evidence. No such process exists for the far more basic mind mosaic, which is only concerned with harmony and disharmony. While a human mind can theoretically operate on the instinctive, mind mosaic (emotional) and intelligence level, the former two are the strongest by far, with the latter generally overwhelmed by the rest.
In such a system made up of individuals unity would thus be accomplished by getting their mind mosaics into a harmonious state, or to have them all basically exclusively use reason. Since neither is realistic with humans, the individuals in any society will seek harmony, cluster together and distance themselves from others. Ideas thereby act more of a poison for unity, with facts being nearly completely irrelevant.
And thus the model of modern human society is fuelled by disharmony, with the only conceivable future a continuing dystopia. Maybe not a full dystopia, as not all individuals in society are this simplistic in their behaviour, yet it will remain the most powerful force within human society for the foreseeable future.