Yes, I have heard the phrase too. My understanding is that you and I are literally not two. Not two is the direct meaning of nonduality.
I am not denying that there are two patterns in the one manifesting as two body/minds. However, it is only within the mind that we separate into two and this illusion is maintained through ignorance. Because there are discernible patterns within nonduality does not mean that there is separation. Like a magnet, there is a north pole and a south pole…this can be discerned…however there is never a north pole without a south pole. You can’t really divide or separate them. The one implies the other…they go together.
Take this picture…
How many aspen trees do you see?
This area is known as the Pando and is located in Utah. You may say you see many, many aspen trees…but there is only one. The Pando is a clonal colony of a single quaking aspen…determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. Due to ignorance, you may have initially believed your eyes and thought there were many aspen trees…but there is only one.
Now if each “tree” had it’s own memories, thoughts, and localized senses, one “tree” might look at a neighboring “tree” and say, “clearly you are other than me…we are two different beings. Your leaves are not my leaves, your senses are not my senses, your thoughts are not my thoughts…so how could we be one?”
In a way, this is like your index finger asking your ring finger the same kind of questions…not realizing both are of one body. The index finger might ask, “why are you so lucky all the time to get to wear the ring?” It is only due to separate memories, thoughts, and localized sensation that we believe we are separate. Different fingers do have different localized sensation…you can prick one finger and it will feel it…but the other fingers do not feel it. All you need is the fingers to have their own thoughts and memories and they might claim to be separate from the others as well.
So if you think you are separate and other from “others” you see, then you too are missing something. We are mistaking what we experience as a localized body/mind to mean we are just a body/mind and separate from everything else. This is an illusion in the mind perpetuated through ignorance.
Again, this is like the north pole and a south pole of a magnet. There is only the magnet, but there are undeniable differences between the north pole and south pole. However, a magnet can not be without a north pole and a south pole. You break off the north pole, you now have two magnets with their own north and south poles. The two poles are never truly separate.
The ignorance perpetuating the illusion could be a very small thing. I sometimes will show a loop made of paper and ask, “is there an inside and an outside?” It is a flat loop and most will say there is an inside and outside to the loop. But what they don’t see is a 180-degree twist in my hand. This makes the loop really a Mobius strip. It is one continuous surface, so there is no inside or outside. The appearance of a loop is an illusion perpetuated through ignorance of the twist.
It is the mind that separates and divides, for even with the knowledge of the twist…it may still look like there is an inside and outside to the loop. You can look at the ocean and see waves…and really think the waves are separate things. There is only the ocean. Only people say these are waves…the ocean doesn’t say such things. We chop things up mentally so we can talk about parts (what they are doing, how big or small, etc.), but then we become deluded into thinking the parts are actually separate things in their own right.
We are deluded into thinking we are separate things in our own right. We are not though. We are all one. We have always been one, it is only our thoughts that say otherwise. When the mind is silent and still, there really isn’t division and separation. There just is what-is…as one (so to speak).
In the same way you might be able to overcome the illusion/delusion and recognize that there are no waves…just ocean; I have realized there is only That. I am That. You are That. There is only That. There has only been That. There will only be That. There is no other. So when this body/mind sees you, there is a knowing that it is only That.