Hi dude,
A very interesting line of inquiry! It's fun thinking about this  :  )

First of all, you've got the same problem I had; Roger's terms are apparently “congruous” (adj.) and  “congruity” (vb). There is no 'congruent' or 'congruence'. This seems quite counter-intuitive to me, and obviously not just to me  :  )

Anyways, we are looking at congruity between unconscious and conscious concepts within each individual; not between people.

We could make the same argument by speculating that enabling congruity could enable large groups of people to develop intelligence and end up behaving 'all the same', ...but we already know that different environments, experiences, behaviors, thoughts, genes and inputs shape us all into different individuals. Consequently when those individuals get congruous (ie, get into sync) they are putting their varied skills together, not all modeling the same set of skills.

The argument works in the sense that there WILL be much that they have in common with regard to basics; most intelligent individuals will be as eating sensibly and sleeping well and not driving across narrow bridges pissed out of their minds, but each individual will be doing “what is best for me personally”, being fully aware that we all have different interests and different needs, not to mention different genes. Consequently all intelligent people would agree on most basics, such as “there is proof that music seems to have benefits to mental health”, but not on details (ie, no  intelligent person would claim only the sort of music THEY like could have those benefits.)

In short, congruity includes the concept of diversity because it makes sense; “we are all different”. Congruity is an attribute required for strong intelligence. The same is true for computers; if a program were accidentally told to let the input '2+2' mean 'print the number 5'  even though another function in worked out correctly that 2+2 = '4', we'd have incongruity (and a stupid programmer)  :  ) The program itself would have no way of knowing which is true, and a database of mathematical facts resting on both these assumptions couldn't be constructed.

It seems unconscious minds (machine or human) can't know about these sorts of mistakes until they are pointed out in conscious awareness and rectified.
Best,
AR

PS Re: association is literally cells firing and even wiring together.
...It IS surprising how often in NH we can get this sense of “Wow, that's bleedin' obvious, why didn't I notice it before”. I've had it about anxiety; grasping the simple concept that it simply cuts off the blood supply to frontal lobes; that's all it needs to do to make us unable to think clearly (which effectively prevents us from even detecting it's happening). It really is that simple  :  )

Hi dude,

This is good fun, and I'm getting it ever clearer in my own mind by trying to explain it  :  )

I may have accidentally misled by using the term, 'synchrony' rather than 'synergy'; the former referring more to physical sync while the latter means 'working together to the same end'. And yes! it is a noun -My bad!

I'll go through T11 at some point and assess this, so:
Re: congruity refers to "synchrony" between networks in one individual's brain.

...Only in the sense that they are working together and not in opposition; not like 'all firing at once'. Congruity doesn't create 'sync'(so 'synergy' is a better term).

Congruity is much more about mind than brain. It's about concepts; beliefs agreeing with reality are congruous beliefs. If you believe you have red hair and you actually HAVE red hair, that's congruity. If you consciously believe you have red hair but unconsciously know you have brown hair, that's incongruity. It sounds so obvious when we put it like this, we may think nobody would ever do that... oddly, most of us do have some incongruous beliefs, usually due to not being able to access our own unconscious knowledge (or due to having been told a load of crap).

There is a great quote from musician Frank Zappa: "If you end up with a boring miserable life because you listened to your mom, your dad, your teacher, your priest, or some guy on television … then you deserve it."    ...I don't quite agree with Frank here but we can see what he means, applied to what we consciously believe.

A great example of incongruity is lots of folks daily tucking into their modified corn breakfasts, consciously believing “cereals are good for you”. Meanwhile in reality the unconscious is getting the chemical messages “Poor nutrition only,” concluding, “There must be a famine; -better start storing loads of fat!” and signaling the genome accordingly. Here the result of incongruity can clearly be a killer.

Re: And the unconscious concepts within an individual are the same for everyone else?

...Unconscious concepts are mainly universal, as the basics are the same for all of us. For example anyone on earth will have shared  unconscious knowledge; things such as: “gravity exists. I am a mammal. Upwards is that way. Behind me is over there. Falling off cliffs is bad. When I feel hunger, then I should try to eat.  When I feel sexy, then I should try to have sex. When I feel tired, then I should try to sleep. I live on a planet.”  These facts are the same for all humans and pretty much the same for all living mammals. The laws of physics and motion, of mechanics and mathematics, are also universal for all of us.

There will be differences according to location (for me, it goes dark every night; for a dude in the arctic, it may not. In my location, the weather is usually shite; some other dude somewhere is lying in the sunshine.) There will also be differences of taste (when hungry, we may eat meat; some other dude may really dislike meat) and genome-related differences (some dude is allergic to meat). We all have different genomes and more importantly we express genes differently due to input & experience, so everyone's unconscious knowledge will be tailored to them personally but each system will have congruity within itself.

What will be very different are the details, for example you may like some foods I don't like, we may both be sexually attracted to totally different people, we may not get tired at the same time as each other. Our tastes in art and music may be different...and so on.
Knowing what the unconscious knows and consciously agreeing with it allows congruous mentality to emerge.

Re: IF all unconscious concepts are universal then for their to be variety then there are many different types of input that would synchronize with the unconscious concepts.

...I'm not absolutely clear what you mean here; variety comes in due to genome/ location/ experience/ input and other factors. Even identical twins express their genes differently according to epigenetic factors, as we know -the older they get the more the genomes diverge. So sure, there are millions of types of input combinations & transcription factors that can fine-tune genetic expression.
Network 5 is pretty essential for self-knowledge, because it can detect our individual differences as adeptly as N4 can detect our similarities. But if I go diving into N5 abilities before we finish N4 (with Tutorial 12) it could get confusing. 
Best,
AR