The brain is an information processing machine and when lay-people use the term "thought" they are generally referring to those aspects of the information processing that are accessible to introspection. When you refer to thought that occurs when you’re not actually “doing” anything I assume you mean information processing that doesn’t immediately lead to some sort of motor output. Well, it’s certainly possible to demonstrate that there is neural activity associated with this sort of processing using various techniques (e.g. EEG, EMG, PET, fMRI).
Is there more to thought than “mere” synaptic chemistry? Well of course, how information is processed depends on how the connections are arranged into a network.
[ 18 August 2001: Message edited by: stagger ]