I sat a monthlong at Forest Refuge recently and the particularly annoying brand of dharma being taught helped me clarify something in the back of my mind about Certainty.
The teacher was disparaging of certain traditions and Theravadan practices in general, although he had been an ordained monk in Mahasi lineage.  Along the way he found some sort of poor man’s rigpa and that is what he teaches as the “most direct, immediate, always available” practice.  He literally said in a dharma talk, “I know that all teachers say their dharma is the best, but mine really is the best.”  It’s cool, he’s 75 years old.  Say whatever you want brah.
Here’s the thing about Certainty.  It’s cool if it’s like, the crypto influencer you follow.  Certainty can give confidence when things seem chaotic.    The downside is large though.Put simply, being Certain precludes any chance for growth and new possibilities.Practically what this looks like is someone coming to this board and declaring something like, “I am a cock, listen to me crow!”You may be nodding and thinking, “right, not-knowing is the most intimate” as is often said in certain pretty zen circles. 

I suggest considering that assertion closely.You may quickly ascertain that not-knowing is absolutely not the most intimate.  The most intimate is touching, fondling, licking, sucking, fucking whatever it is that one is intimate with.  Perhaps it could be more accurately said as “realizing that one does not-know encourages one to try to know.”I suppose what I’m trying to say here is that I am certain that it is unwise to be Certain about anything.

Being certain basically cuts off curiousity about new information. And new information is needed to change with changing situations. 

Certainty usually resides in the realm of thoughts and emotions _about_ the situation. The situation itself is fundamentally unknowable but what we do know comes from our human senses. 

If uncertainty is also in the realm of thoughts and emotions _about_ the situation --- one type of uncertainty ---  then it is just as blinding as certainity. But if uncertainty redirects attention back into the felt experience of the situation --- a different type of uncertainty --- then uncertainty leads to fresh experiencing, new information, and a better ability to respond in the moment. 

People who "know what they are doing" in bed are usually mediocre lovers because it's just a dead formulatic thing.

People who are full of emotional and intellectual uncertainty in bed are usually the worst lovers, because it is all about their doubts and insecurities and struggling to overcome it.

People who are uncertain about making love, but who are into the actual felt experience of touching, fondling, licking, sucking, stroking --- and how it changes and responds to how each other is changing --- and who's minds are not filled with thoughts but rather filled with the unknowable koan-like riddle of jointly-created felt sensations "are these sensation mine, theirs, or ours... or somehow all of these and yet how can that be? Wow."  Folks that are having sex like that are very fun to have in bed.

Disclaimer: the DharmaOverground neither promotes nor dissuades sexual activity. Please choose your celibacy or partners wisely. Please ensure consent. Please use appropriate protection because bodies are gross and icky and full of diseases. Eeeew. And yet sex is yummy. Dang this world is complicated.

Ehm ... are you trying to tell us how good of a lover you are shargrol  

No, now I know what I'm doing.

Uncertain!  

Certainty - tempered by openmindedness - is fine and well, and a natural consequence of high level achievement on the path.  The issue you seem to have run in to is how it's expressed. 

Yeah knowing things like even simple things like 1+1 and being "certain" the answer is two while at the same time realizing we are in the realm of mathematics and we are doing addition. Open to other answers but making "assumptions" that everyone sort of agrees on. That can present as arrogance when one person is at a much higher level of understanding than another, and 1+1 is obviously two, but to someone just learning to add it may seem like the person to whom it is obvious, is an arrogant prick. 

I think certainty is a transient symptom of insight into the nature of mind, and sometimes it feels like we really know something.

What I realized is that we are all bozos trying get through life ala RAW. What recently disturbed me is :https://en.wikipedia.org/wiki/Introspection_illusion#:~:text=The%20introspection%20illusion%20is%20a,treating%20others'%20introspections%20as%20unreliable. .

Like how our introspection can be unreliable etc, which made me think of the meditative practices but there are also studies that show meditators are better at introspection hmmmm.

Another way to put it - there's a Tibetan Buddhist Mahamudra book called "the journey to certainty", and this title in many ways sums up progression on the path.

When we start out in meditation, teachings on deeper states of mind and the fruits of the path (ex: the jhanas, emptiness, the nature of mind, etc) are abstract and our only real connection to them is at an intellectual level.

However as we progress and begin to experience these things first hand, we become more and more certain about the realities of this teachings.  Certainty in this sense implies a personal experience of progress on the path, and thus is developed slowly and gradually over time.

Are we still fallible, can we still sometimes be mistaken about the profundity, finality, or absolute nature of our attainments? Definately - certainty in our personal experience and achievements is still very much subject to being humbled.

But on the whole, the path is not a kind of "treadmill of uncertainty" - it's very possible to both progress on the path and to rationally and appropriately recognize it as such.

I think its a good point. I am in and out of certainty, and its a advice I got from a dharma friend reg insight practice; aim for certainty, nothing else works really. That being said, we are also pretty certian in our egos and that shit goes on forever really, so what do we do then?

It sort of is the friend of honesty, or related or something. Its the real deal     

It took over a thousand pages in Principia Mathematica to prove 1 + 1 = 2

We can try to use a linear explanation; 

There is a river. Down the river and up the river. 

We look at it and see stuff arise-passing ... we see stuff, waves/objects floating away, one after the other. We grow certain about it. All sorts of waves/objects float down , passing away. We are certain about all these different waves through memorising. We do not question memorising as maybe being false. We grow certain. 

But then we look upstream and stuff (waves/objects) keep pouring in so fast and Im uncertain what is what. I'm uncertain what is coming in next. It's a bit like standing at the very well of the stream/river and I just don't know what's coming next out if it. I'm utterly uncertain and I lose control. 

Then I might panic and chose to look down the stream again and feel at home in my certainty about how stuff arises-passes in certain wave form (Jhana, Nana ...) I fall back into Paths. The Familiar ground. I feel better in this Jhana or Nana or calmness and tranquility etc ... 
It can be scary staring at uncertainty. 

​​​​​​​This but my view. Is subject to change. 

Yeah, and its not true, its 9 everyone knows.. gosh what a waste!

Yeah, if you define "9" to be 1 + 1 then you're right. It's mathematics, you can do whatever you want

Indeed l did actually gain a bachelor in philosophy, but didnt feel l deserved it. Reg philosophy of mathematics l certainly lack some IQ points and patience to get properly into it. It is facinating of course even for an outsider how much "how" you can ask, even in mahs, is there ever an end? Or do we need to move from intellectuality to direct experience?