“Why you got a new phone?”

Those words, spoken by my three-year-old immediately upon seeing it for the first time, are all anyone really needs to know about iOS 7. It’s a reimagining that catapults the system into a new era while retaining the most important intuitions built up over the last six years. So much has changed, yet the changes themselves are so basic. As Lessien wisely noted months ago, iOS didn’t need to change that much. The biggest risk was change for the sake of change: losing the efficiency that familiarity breeds.

Apple has kept all the right things, and built a new experience celebrating the values behind them. iOS 7 is truly the sum of its parts. On their own, many of these new elements — parallax, translucency, animations, motion — might seem out of place, even gimmicky. Together, they put forth a clear vision, one that’s reinforced by one of the best marketing videos I think Apple has ever made. Even considering Apple’s famously deliberate style, the choice and use of words in this video (and other WWDC materials) stand out: Clarity. Depth. Vitality. Detail. Deference. Realism.

It’s the realism I want to talk about. John Gruber calls it “A real thing, not pixels rendered on glass.” Rene Ritchie says “iOS 7 is alive.” This is the sort of update I was hoping iOS 5 would be nearly two years ago.

What took so long? I think it was a combination of hardware and momentum. Not so long ago, Steve Jobs was telling users that wallpapers were too slow. The deep animations and real-time blur effects you see between layers in iOS7 are all hardware-intensive operations. The tug of war between “realistic” design and hardware limitations led to an early compromise of false illusions — shadows, bevels, borders. Once these trends are in place, it’s hard to buck them.

Now the hardware has caught up, and the Apple design team has a new leader. We don’t need the deception of “photorealism” anymore. Despite the loss of these tricks, iOS 7 feels more real. The parallax effect conveys an entire living world under that glass, not just abstract pictures and icons. This is reinforced by the launch and quit animations: your eye never loses sight of where you’re going, or where you came from. You are moving through this world. There is almost no change in context, ever.

The emphasis on text is also striking. More than just content, text has replaced iconography in many cases. Look at Camera: the modes — VIDEO, PHOTO, SQUARE, PANO — are represented by text for the first time ever on iOS. This to me is proof that “clarity” has taken top priority. iOS is available in a number of countries and languages, which means every piece of text has to be localized (translated) many times over. This isn’t only time consuming, it’s disruptive to UI design: a short word in English is not necessarily short in German, and suddenly things don’t fit on screen anymore. I attended many meetings at Apple where people cringed at changing a word shortly before release, because it meant a whole new round of localize-then-build-then-test.

Icons avoid this problem — when done right. They speak no language, which is to say every language. Or they can only speak a few. The truth is, images have nearly as much cultural variance as text. They say a picture is worth a thousand words, but sometimes a single word is worth a thousand pictures. That realization, raised above any logistical or procedural consequences, tells me just how serious this new philosophy is.

Clarity. Depth. Vitality. Detail. Deference. Realism. The revelations of iOS 7 are overdue, but still quite welcome.