 Wonderful things will happen if I raise both my arms at some given time t. OK things will happen if I raise neither arm at t, and also if I raise my right arm but not my left arm at t. Dreadful things will happen if I raise my left arm but not my right arm at t. If I raise my left arm at t, I will not raise my right arm at t. I am completely free to raise or not to raise either of my arms at t. Let’s suppose that all the foregoing is known for certain by me at the time in question. (2014: 645)