Stimulating points on the cerebral cortex with the tip of an electrode can make a subject experience various sensations. A patient may move an arm and experience this movement as external, i.e., not originating from the subject, experienced as a reflex. Some have taken this to show there is part of the mind (higher order cognition, perhaps) immune to physical manipulation because such stimulation does not manipulate the intentions of the subject. Neuroskeptic explains why it isn’t surprising that stimulating points on the cerebral cortex doesn’t affect the intentions of the subject:
[T]o take this as evidence for some kind of a dualism between a form of conciousness which can be manipulated via the brain and another, non-material level of conciousness which can’t (the “soul” in other words), is like saying that because hammering away at one key of a piano produces nothing but an annoying noise, there must be something magical going on when a pianist plays a Mozart concerto. Stimulating a single small part of the brain is about the crudest manipulation imaginable; all we can conclude from the results of point-stimulation experiments is that some kinds of mental processes are not controlled by single points on the cortex. This should not be surprising, since the brain is a network of 100 billion cells; what’s interesting, in fact, is that stimulating a few million of these cells with the tip of an electrode can do anything.