>in general, you can't know what the program will do until you run it

It needs to be added that in Common Lisp, once the program is running you can do everything with it while it's running: Inspect the stack frames, change variable values, rewrite/recomiple/update functions, update class definitions, update objects to said new class definitions, save the current program state to disk,etc.

So it's programming that is geared to RUNNING the program and modifying it while its running.