We still don't have much of a theoretical understanding of many things in medicine and healthcare, or have since learned that what we thought was a theoretical understanding is grossly wrong. Usually, the only way we can get any closer to such an understanding is by performing what are essentially experiments on people and seeing what happens, particularly people already suffering from horrific diseases and injuries. It may be disturbing and scary in some ways, but that's how things work.

I wish medicine were more like theoretical physics. I understand that it’d be difficult to come up with theories that could fully explain complex brain functions and diseases like Alzheimer’s. It’s also difficult to test those theories safely without crossing ethical boundaries. Being either overly cautious or overly optimistic could lead to bad outcomes. It seems like we need a reasonable balance.