Second rules out cause though. If you have A=>B and B=>A as possibilities, and you can rule one of them out with a very simple question, that's a good way to start.
If computers came after electricity, they didn't cause electricity. That says nothing about the possibility of electricity causing computers, but it brings us forward nonetheless.
If computers came after electricity, they didn't cause electricity. That says nothing about the possibility of electricity causing computers, but it brings us forward nonetheless.