Well Nigel, I see it this way. People have often claimed to be able to multi-task, while in reality these people are only using time division multiplexing, and this has been proven by scientist using MRI imaging. Now I did post my comment facetiously, but since you flat stated I am wrong, I feel compelled to reply. Multi-tasking by definition is the ability to perform two or more task at one time, and by this definition, if an interrupt is asserted to the main control function eg. a microprocessor, to halt one operation to perform another, then I claim it is not multi-tasking but rather it is using time division.
I am still sort of being smarty pantsy...