What about a complex codebase with nearly 8 billion subtly different running copies? Your copy has a bug, so you find a copy that doesn't and monkey-patch the a

What about a complex codebase with nearly 8 billion subtly different running copies? Your copy has a bug, so you find a copy that doesn't and monkey-patch the assembly. Have you fixed the bug? Unless it was in some initialization code that won't get run again, your odds are pretty good. A lot of genetic disorders are simply "whoops, your gene for X protein/enzyme/whatever is corrupted". I'd sure be tempted to patch that in myself.