> There's clinical evidence that such a location in/on the human body represents the true effective residence of human sentience, since snipers target precisely that location to take out their targets, before they have a chance to (even reflexively) react to their wounds.

It tells you no such thing. In a distributed system if you take out the main ethernet switch (interconnect) you can bring the whole system to a halt, but that doesn't mean the computation happens there.

Now, no kidding: there's a massively parallel (80 G neurons x 10^ fanout) machine with a ~ 100 Hz clock inside your skull, but there's a lot of computation going on elsewhere. Look at what I said about all the neurotransmitters in your gut, not to mention the rest of your reticulated nervous system. And people do plenty of things all the time (e.g. hit a baseball) that require a response and feedback faster than the nervous system can transmit from the big bag o' neurons to the wrist.

I'm not saying you're wrong; I'm saying there's far, far from enough evidence in contemporary neuroscience to support the level of confidence you exhibit in your theory of mind.