I don't know how one would build anything without knowing. If it was true, I would be building a competitor to Anthropic right now.
I mean only people with billions of dollars can make competitors to anthropic because of necessary compute costs
that's the barrier to entry
You build without knowing by delegating to a system that extrapolates what it knows about you and what you want, and is able to execute on that to deliver faster, better, and more completely than you ever could. You'll live as a ball of intent and values, observing in wonder as everything you desire springs up around you before you know you want it. You could choose not to live like this of course, but it would be like driving a DIY go-kart on the highway - you'll fall behind and get in others' way, and the rest of society will treat you accordingly.
That's the optimistic case, anyway.