Popper about theories and uncertainty

Is empirical science what we call science?

This is key in Popper's approach. On one hand, this Russian dolls kind of evidence is about theories. Theories are depending on the present knowledge, on present possible observations or present power of conceptualization. With time and improvement of techniques, they are wrong on some conditions. On the other hand, Popper approach deals with uncertainty. His major contribution in my opinion. From the present uncertainty level to a less uncertainty level the path is the falsification of links either causal ones or other links and relationships.

The two are very intertwined. A theory could be considered as a level of uncertainty. In a sense from one theory to a more appropriate we are just going to a less uncertain description of the world.

Q&A
"But were a theory refuted like a brick atop another, we just might end up building a wall in a row upon row of falsifiable?"

No, we will use bigger bricks or new bricks to replace all the falsifiable ones.

"Not sure how you refute any theory which goes beyond three-dimensional time-space. The string theory, multiverse etc."

First, these theories are very uncertain according to Bayes theorem. Second, it could take time but we will be able to do it.