|Source: Wikimedia Commons|
As Marc in Empire Records says, "who knows where thoughts come from, they just appear."
Unless you get in an fMRI scanner at McGill, of course. Then, well, your thoughts will still appear from nowhere, but you'll really really believe that they implanted them in your brain.
It's a fun study: they had participants getting an fMRI machine and told them that they were either in a "mind reading" or "mind influencing" group. Using some basic stage magic, they tricked the participants into thinking that a number that they thought of had been written on a piece of paper beforehand.
People in the "mind influencing" group reported after the fact that they felt like they had less control over their own thoughts and even said that they felt the number being inserted into their brains.
Obviously, we aren't really incepting peoples' thoughts yet, but the placebo effect is pretty powerful. Maybe convincing people that they have been incepted is as impactful as actually incepting them.
Source: BPS Research Digest