"Nondualism" is essentially the resolution (by transcendence) of traditional dichotomies....idealism vs materialism....observer vs observed...self vs non-self...etc. It is the recognition that all boundaries are transient, and hence the concept of static class membership on which "logic" is based is always of limited application.
If we speak of dualism as the dichotomy body/soul, physical world/spiritual world, then I am not a dualist.
If the starting point of any philosophical idea about us is in our presence in experience, as I believe it is, that doesn't mean an experience subject/object in the cartesian tradition. Here I agree with you.
I see our experience between things - whatever "things" are - in two levels. First, our experience is intentional, external stimulations are already suposed in the ways we are present. If I need an hammer to do some work, and the hammer is in the other side of the room, the hammer is "near at hand", I mean, even if I have a saw in front of me, the hammer is closer because it belongs to my "circumvision" and the saw does not.
In fact, what I experience is not the hammer in itself. It is that thing that is used to do this or that, and that I learned is called hammer.
What I mean by this is that my experience of things occurs within conditions that are in me, not in things. Or better, things as I experience them, are in me. The hammer can be used to hurt somebody. But "that hamer used to hurt" is not in my experience in this moment; only the hamer "to do the work I planned".
We have a presence - we are that presence - and the conditions of the presence give the meaning to things. Intentionality being the field of a previous "meaningful" experience.
This said, traditional dualism has no place in this kind of perspective. Language, itself, is part of the conditions of my intentional experience.
Let me give you another example: there is a sign in the road that says: "Lisboa, 60 km".
- I live in Lisbon and I am driving in that road, anxious to get home and take a shower. The meaning of the sign is: "another 40' to get home!".
- I am a worker of the road and built that sign. It's meaning is: "I should have put it more to the left".
- My son died in an hospital in London 3 months ago. The sign means: Last time we were together it was in Lisbon and he was so happy to see a football match of Benfica!
It is not a problem of definitions. It is how things appear to me, within the reality of my experience conditions.
Here, I repeat, there is no dualism.
But see this other situation.
We both are in the car in that road. You don't speak portuguese. You see the sign and ask: what does it say?
And I answer: It says that we are at 60 km from Lisbon.
Here we have a definition as translation. It is as if the sign disappeared as thing, and we are dealing only with language. Because that is not what the sign says. The sign doesn't say anything in english. I am saying it. We are talking about words.
In this case, it is as if our presence in the world becomes abstract. We are reduced to propositions that are self predicated, echanging meanings in our languages.
Dualism reappears when we "cover" our presence and go to an imaginary place "behind" experience.
That is the case of science. I insist as I did before, that science veils our presence, and becomes by that a system of coherent languages, whose propositions have only meaning within those languages. Science does not refer to things of experience (whatever things are). But when it does, when an experiment is being made, the object of the experiment becomes the hammer of my example. The scientist tests a theory within his "circumvision".
To give you an example: 2+2 = 4? Yes, within a system were 2+2 = 4.