There's a lot of abstraction that takes place even at a preconscious level. For instance, in the visual cortex groups of individual "pixels" (for lack of a better term) are analyzed to see which pattern they exhibit strongest. If it's found that such-and-such 50 pixels are showing, say, a diagonal edge, then what is passed on to the next level is a single piece of more "meaningful" information: there is a diagonal edge at this point. The trick, is to realize what happened here: 50 points of a certain nature became one point of a different nature: lots of useless information was boiled down into a small amount of useful information.
This happens all OVER the place in the brain, all the time: lots and lots and lots of data is sifted through and sifted through and just a little tiny bit is passed on, like an accountant who looks at all the transactions, all the financial data of a company, and then gives a quick "highlights" report to the CEO.
What we think of as reality is really just a very narrow collection of the things that "matter" to us. If the refrigerator is kicks on, we hear it, and then almost immediately stop hearing it because basically our brains/minds (software/hardware/is there a difference?) decide it's not really relevant and that it's more important to spend time processing, for instance, thoughts and opinions about the Obama campaign, or when our bills are due, or something.
Right here in the room, there are literally millions of little "truths" that may seem rather mundane, such as "the rug is 2 inches from the wall", "the cat is licking itself", "the plume of smoke coming off the incense just started creating steady ripples", "the light is making a light buzzing sound", "a dog just barked", "I'm exhaling", "when I inhale, there's a slight difficulty when I'm about 70% of the way through the inhale", "I can smell the soda in the glass on my desk; it's lemon-lime".
They may be "mundane", and they may be "meaningless", in that they don't contribute to the great goals of your life such as building a stock portfolio or determining whether the universe will eventually collapse into an enormous black hole or whether this is the first and only universe or whatever else. But they are true, as true as anything can be, even more true, more undeniably and unarguably true, than "we are in a recession", "global warming is happening", "wal-mart is a bad company", "I should finish my homework". All of these, of the second set, are the sorts of things we present to ourselves as rock-solid truths, when in reality their firmness, even the extent to which they actually have a fixed meaning, pales in comparison to the truth of "my knees hurt".
To come back to the moment is to play in the realm of certainty, in the rock-solid foundation of Reality. All the other stuff is like a big game of pretend when compared to "there are goosebumps on my left arm".
We have two things going on. We are at once immersed in a sea of this Reality at every moment, and we are also swapping and trading language memes about "atoms" and "politics" and "society" and "commerce" and "the news" and "vehicle safety" and "the war in iraq" and "global warming" and "my retirement fund". To spend all our attention and energy on the immediate Reality is basically to become useless to society, to have nothing to say, to be a non-person. And the spend all our attention on the language memes is basically to become useless to our sensual consciousness. Balancing the two starts with recognizing the difference between them.