On Mon, Oct 3, 2011 at 10:08 AM, Craig Weinberg <[email protected]> wrote: > On Oct 2, 7:00 pm, meekerdb <[email protected]> wrote:
>> If they are part of the same thing, then it is presumptuous to say one >> causes the other. >> One might at well say the neurons firing caused the thought of gambling - >> and in fact that >> is what Stathis is saying and for the very good reason that a little >> electrical >> stimulation, that has no "thought" or "sensorimotive" correlate, can cause >> both neurons >> firing AND their correlated thoughts. But thoughts cannot cause the >> electrical stimulator >> to fire. So it is *not* bidirectional. >> > > What do you mean? Thoughts *do* cause an electrical detector to fire. > That's what an MRI shows. You could use any kind of electrical probe > or sensor instead as long as it is sufficiently sensitive to detect > the ordinary firing of a neuron. That's how it's possible to have > thought-driven computers. > http://www.pcworld.com/article/129889/scientists_show_thoughtcontrolled_computer_at_cebit.html The device cited picks up electrical impulses from the scalp. The electrical activity comes from the neurons firing in the brain. These neurons may have associated thoughts when they fire but this is not obvious to an external observer: all that is obvious is that a particular neuron fires because of various measurable factors such as its resting membrane potential and the neurotransmitter released by other neurons with which it interfaces. So to an external observer, every neural event has an observable cause, generally other neural events. This means the externally observable behaviour of the brain is computable, even though the external observer may not know that the brain is conscious. On the other hand, if the external observer does not know about neurotransmitters and receptors he will not be able to explain why the neurons fire - it will look to him as if they fire for no reason. The mental is supervenient on the physical, but the mental cannot as a separate entity move the physical. If it could, we would observe neurons breaking physical laws. -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
