Much like Boris Karloff in the classic Frankenstein movie, I’ve attached electrodes to myself. One is on my left eyebrow, the other high on my right forehead. When I ﬂip the switch, I see a ﬂash of light, and a thousandth of an ampere of current surges through my head. The electrodes burn slightly. Some other practitioners of transcranial Direct Current Stimulation report increased focus, greater creativity, or relief from severe depression. I just feel weird. It reminds me of my ﬁrst earthquake. An earthquake is not quite like having your body shake, or your chair shake, or your house shake. The world shakes. The world, a ﬁxed frame of reference you’d always taken for granted, becomes unﬁxed. A milliamp through the brain is nowhere near as earth-shaking, but it’s just as weird. You know that feeling you have when an electric shock isn’t being applied to your brain? That feeling goes away, and with it one more assumption about the way life works.