I frequently hear people make the claim that progress in theoretically physics is stalled, partly because all the focus is on String theory and String theory doesn't seem to pan out into real advances.
Believing it fits my existing biases, but I notice that I lack the physics understanding to really know whether or not there's progress. What do you think?
This ignores the possibility of advances in the teaching of math (or physics, or any other discipline). If improved teaching methods lower the level of intelligence required to reach a given level of knowledge, then a field can advance considerably.
Not to mention that the human population has been growing, and average intelligence has been increasing.
Finally, there's specialization. It doesn't take much intelligence to know everything that was known about genetics when Darwin was alive, but probably nobody is smart enough to know everything that was known about it in 2000. But there have still been make advances since then thanks to people specialized in subfields like DNA sequencing.