The greatest pitcher must be a contemporary pitcher (I really don't care what anyone says--I'm incurious that way). Clemens it is. It's probably not even close.
Twenty years from now, someone will blow Clemens out of the water. As long as they keep pumping up milk and meat with 'roids and other insane additives
and smoking diminishes to non-existence and exercise becomes more targetted and efficacious, the human animal will continue to outpace its predecessor.