I think it's pretty clear that the future of books is digital. I'm sure we'll always have deckle-edge hardcovers and mass market paperbacks, but I imagine the physical version of books will soon assume a cultural place analogous to that of FM radio. Although the radio is always there (and isn't that nice?), I really only use it when I'm stuck in a rental car and forgot my auxilliary input cord. The rest of the time I'm relying on shuffle and podcasts.

I love books deeply. I won't bore you with descriptions of my love other than to say that, when I moved back from England, I packed 9 pounds of clothes and 45 pounds of books in one of my checked bags. (I have a weakness for British covers.) And when my luggage was over the fifty pound airline limit, I started chucking T-shirts.

So I'm nervous about the rise of the Kindle and the Nook and the iBookstore. The book, after all, is a time-tested technology. We know that it can endure, and that the information we encode in volutes of ink on pulped trees can last for centuries. That's why we still have Shakespeare Folios and why I can buy a 150 year old book on Alibris for 99 cents. There are so many old books!

And yet, I also recognize the astonishing potential of digital texts and e-readers. For me, the most salient fact is this: It's never been easier to buy books, read books, or read about books you might want to buy. How can that not be good?

That said, I do have a nagging problem with the merger of screens and sentences. My problem is that consumer technology moves in a single direction: It's constantly making it easier for us to perceive the content. This is why your TV is so high-def, and your computer monitor is so bright and clear. For the most part, this technological progress is all to the good. (I still can't believe that people watched golf before there were HD screens. Was the ball even visible? For me, the pleasure of televised golf is all about the lush clarity of grass.) Nevertheless, I worry that this same impulse - making content easier and easier to see - could actually backfire with books. We will trade away understanding for perception. The words will shimmer on the screen, but the sentences will be quickly forgotten.

Let me explain. Stanislas Dehaene, a neuroscientist at the College de France in Paris, has helped illuminate the neural anatomy of reading. It turns out that the literate brain contains two distinct pathways for making sense of words, which are activated in different contexts. One pathway is known as the ventral route, and it’s direct and efficient, accounting for the vast majority of our reading. The process goes like this: We see a group of letters, convert those letters into a word, and then directly grasp the word’s semantic meaning. According to Dehaene, this ventral pathway is turned on by “routinized, familiar passages” of prose, and relies on a bit of cortex known as visual word form area (VWFA). When you are a reading a straightforward sentence, or a paragraph full of tropes and cliches, you’re almost certainly relying on this ventral neural highway. As a result, the act of reading seems effortless and easy. We don’t have to think about the words on the page.

But the ventral route is not the only way to read. The second reading pathway - it’s known as the dorsal stream - is turned on whenever we’re forced to pay conscious attention to a sentence, perhaps because of an obscure word, or an awkward subclause, or bad handwriting. (In his experiments, Dehaene activates this pathway in a variety of ways, such as rotating the letters or filling the prose with errant punctuation.) Although scientists had previously assumed that the dorsal route ceased to be active once we became literate, Deheane’s research demonstrates that even fluent adults are still forced to occasionally make sense of texts. We’re suddenly conscious of the words on the page; the automatic act has lost its automaticity.

This suggests that the act of reading observes a gradient of awareness. Familiar sentences printed in Helvetica and rendered on lucid e-ink screens are read quickly and effortlessly. Meanwhile, unusual sentences with complex clauses and smudged ink tend to require more conscious effort, which leads to more activation in the dorsal pathway. All the extra work - the slight cognitive frisson of having to decipher the words - wakes us up.

So here’s my wish for e-readers. I’d love them to include a feature that allows us to undo their ease, to make the act of reading just a little bit more difficult. Perhaps we need to alter the fonts, or reduce the contrast, or invert the monochrome color scheme. Our eyes will need to struggle, and we’ll certainly read slower, but that’s the point: Only then will we process the text a little less unconsciously, with less reliance on the ventral pathway. We won’t just scan the words – we will contemplate their meaning.

My larger anxiety has to do with the sprawling influence of technology. Sooner or later, every medium starts to influence the message. I worry that, before long, we'll become so used to the mindless clarity of e-ink - to these screens that keep on getting better - that the technology will feedback onto the content, making us less willing to endure harder texts. We'll forget what it's like to flex those dorsal muscles, to consciously decipher a literate clause. And that would be a shame, because not every sentence should be easy to read.

Bonus point: I sometimes wonder why I’m only able to edit my own writing after it has been printed out, in 3-D form. My prose will always look so flawless on the screen, but then I read the same words on the physical page and I suddenly see all my clichés and banalities and excesses. Why is this the case? Why do I only notice my mistakes after they’re printed on dead trees? I think the same ventral/dorsal explanation applies. I’m so used to seeing my words on the screen – after all, I wrote them on the screen – that seeing them in a slightly different form provides enough tension to awake my dorsal stream, restoring a touch of awareness to the process of reading. And that’s when I get out my red pen.

Bonus bonus point: Perhaps the pleasure of reading on my Kindle - it's so light in the hand, with such nicely rendered fonts - explains why it has quickly become an essential part of my sleep routine. The fact that it's easier to read might explain why it's also easier for me to fall asleep.