Google has published a design language with actual rules in it, and I find myself unexpectedly moved.
Material is a real attempt at a philosophy, not just a mood board. There is a physics to it. Surfaces have thickness. Things cast shadows because they sit above other things. Motion has a reason, because an object that moves is telling you where it came from and where it went.
After the great flattening, this feels like a correction I did not know I wanted. Flat told the truth about screens and then forgot that a person needs to know what can be pressed. Material says, all right, we will build a fiction, but it will be an honest one, with laws that hold.
What I admire most is that it is written down. Not a feeling, not a board of pictures, but stated principles that a team of a hundred people can argue with and follow. That is what makes a system rather than a style.
The risk is plain enough. Give the world a beautiful rulebook and a great many people will follow it exactly, and everything will start to look like Google. A rulebook is not a substitute for judgment. It is a floor, not a ceiling.
Still, I will take a stated floor over an unspoken one. Rules you can see are rules you can argue with. It is the invisible conventions, the ones nobody wrote down, that quietly run our work without anyone ever examining them.