Just now I remember what Thorne's answer was to my question. Something like, "you could reduce space-time to three dimensions, but the mathematics is too complicated."
Forty years later, because of Ilya Prigogine and a kiss from Einstein, I find this answer sufficient: without time no motion is possible. Without motion there is no energy. Without energy there is nothing. Even string theorists agree. We impose time on our experience because we are energy machines, requiring food and elimination due to the second law of thermodynamics. Finally, this is pure speculation, Einstein's theory of gravity may just be just another consequence of the second law. When bodies interact, say finally as in the relatively stable current orbit of the Moon and Earth, isn't that just another equilibrium state on the way down the energy spectrum? I believe this is what Prigogine calls metastability.
After a quick look at Wikipedia on metastability and ground state, my head is starting to hurt again so I need to take a walk. Not a random one because there is no destination, just wandering around in circles until I finally remember where our door is. Such is life, 43 perhaps?