For the duration of this post I want you to forget about your model of reality and return to your raw experience of the world. If you hear a sound, for example, forget the idea that there's some object causing the sound, some subject ("I") receiving it, some sense organs and neurons mediating the experience, etc.
Okay, let's try this.
Silence is the absence of sound. Now, pay attention to any particular sound in your environment, and recognize it as the presence of sound. "A sound" is some particular presence of sound.
Now close your eyes and notice a (relative) absence of light/color. Now look at something, and recognize it as the presence of color.
You can do the same thing with your other senses. Compare the presence of a feeling (like pressing your fingers together) with an absence of feeling (in that location, at least).
The senses are all different modes of presence, but what they have in common is presence itself. Now spend a minute and see if you can intuit what I mean when I say that presence is the very "stuff" out of which all experiences are made. Presence, modulated in various ways, is the sole substance of your perceived world. Really take a moment and notice this.
It is also the sole substance of your thoughts, memories, emotions, etc. Every single thought you've ever thought, like every sound you've ever heard, is "made of presence." For the most part, we do not even notice the existence of our thoughts, let alone carefully inspect their texture. Beginning meditators can spend weeks or months, possibly requiring retreats with constant practice, before noticing just how busy their minds have always been.
This can be hard to believe, since it's so counterintuitive. But if you've ever been reading a book, only to discover "crap, I thought I was reading, but I was really daydreaming," then you have all the evidence you need: you're consciously doing tons of stuff that you just haven't realized yet. What secrets lie in that murky deep?
Slowly you may discover that even your sense of identity is just a cluster of thoughts. There's nobody there, sitting inside your head, looking out at a world. You may already know this from neuroscience, but now you experience it directly.
As this happens, you might start to reevaluate the belief that "I am conscious." Who, pray tell, is conscious, if there's nobody there?
And now, slowly, slowly, it occurs to you that "consciousness" is just another word for what we've here been calling "presence." It's not that there is some object called sound, and a subject called I, and some abstract property called "consciousness" that magically links the two. Or rather, that model of reality may be useful, but it's not your actual experience of the world -- even though it has always seemed like it due to unexamined conceptualization. Instead, this shimmering show you call "life" is all consciousness, all the time. In a sense, it has always only been experiencing itself.
So now what do you do with a belief like "consciousness exists" or "consciousness does not exist?" You discover, directly, that those beliefs are made of the very "stuff" they are questioning. Even the concept of "exists" or "real" are made of it. Any answer you might muster is also it.
The sweater begins to unravel. A remarkable charade is exposed.
In each moment, the luminous fabric of consciousness weaves itself into a dazzling array of sensual delights, as well as a thicket of mutually reinforcing beliefs that together form your conception of reality. Beliefs form, such as "there must be a real world out there, responsible for all of this glory," and "these memories and expectations must prove that time is real." Whether or not any of that stuff is true, it is astonishing to discover how these beliefs really form (and re-form) in each moment.
Remarkably, during this model-building phase, consciousness brilliantly hides itself from itself, taking on fiendishly clever forms such as "the stuff of the world (aka matter) is all that really exists; consciousness is just an illusion." And like a snake eating its own tail... poof!, the sole substance of your reality seemingly vanishes into itself.
But it's always hiding in plain sight. It is what the Tibetans call "self-secret." It's not that some yogis in an ancient cave have been hiding it from you. It is everything. Yet somehow you are continually hiding it from yourself. This game of hide-and-seek is known as Awakening, and it can go on for as many cycles (lifetimes) as you wish.
This isn't a physical or philosophical fact, but an experiential one. Of course it doesn't prove anything about the world, but it's not meant to. Instead, you can consider it as a pointer to a peculiar mental habit we all have -- or in a sense, that we all are.
So close you can't see it
So simple you can't believe it
So deep you can't fathom it
So good you can't accept it
-- Tibetan Buddhist saying
(All that said, I still need a word to describe the fact that the organisms I experience are interacting with the world. I'm perfectly happy to use the word "consciousness" here, and study it scientifically. These things are probably, but not necessarily, related. That is, perhaps I can experience a world without being able to interact with it, or vice versa. The conflation of these two facts has led to no end of philosophical and scientific trouble.)