Suffering; everything that feels bad and horrible, fear, pain, depression, is caused entirely by the brain.
Modifying our surroundings won't get rid of it. We could end hunger, achieve perfect equality, and make the world a paradise. But suffering would still be there. The hedonic treadmill ensures that our brains will find new things to be anxious and depressed about.
The only way to truly be rid of suffering is to find the parts of the brain that cause it and do away with them.
A recent guest post on Astral Codex Ten, "Absurd Adventure and Amygdalectomy Advocacy," was written by a man who had his amygdala removed during surgery for cancer. This resulted in the abolition of anxiety and a massive reduction in general suffering.
These results came from accidental damage. Imagine what could achieved with research to work out exactly which parts of the amygdala to remove in order to reduce suffering while minimizing side effects. And brain surgery need not be invasive: endoscopic methods can ablate brain tissue through only a few small incisions. Radiosurgery is less invasive still.
