"Suppose you are to be executed by a firing squad of 100 trained marksmen, all of them aiming rifles at your heart. You are blindfolded; the command is given; you hear the deafening roar of the rifles. And you observe that you are still alive. The 100 marksmen missed!"
Taking off the blindfold, you do not observe that you are dead. No surprise there: you could not observe that you are dead. Nonetheless, you should be astonished to observe that you are alive. The entire firing squad missed you altogether! Surprise at that extremely improbable fact is wholly justified - and that calls for an explanation. You would immediately suspect that they missed you on purpose, by design."
suppose you are dragged before a firing squad of 100 trained marksmen, all of them with rifles aimed at your heart, to be executed. The command is given; you hear the deafening sound of the guns. And you observe that you are still alive, that all of the 100 marksmen missed! Now while it is true that:
You should not be surprised that you do not observe that you are dead, nonetheless it is equally true that;
Given the fact that 100 marksmen were aiming for you, you should be surprised that you do observe that you are alive.
Since the firing squad's missing you altogether is extremely improbable, the surprise expressed is wholly appropriate, though you are not surprised that you do not observe that you are dead, since if you were dead you could not observe it. Similarly, while we should not be surprised that we do not observe features of the universe which are incompatible with our existence, it is nevertheless true that we should be surprised that we do observe features of the universe which are compatible with our existence, in view of the enormous improbabilities thereof.