> For instance, people did lament the invention of calculators, saying it would harm kids' ability to do mental arithmetic. And it did.

> Fortunately for us, we replaced those skills with technology that allowed us to do something analogous to them, but faster and more easily.

Don't kids still learn to do arithmetic in their head first? I haven't been in a school in decades but I remember doing it all sans calculator in elementary school. When you move on up to higher level stuff you end up using a calculator, but it's not like we skip that step entirely, do we?