You are about to toss a coin. The chances are equal – 50/50 – that it will come down heads or tails.
The toss is now completed.
But this is a thought experiment. The toss was carried out under controlled conditions in a laboratory; you tossed it over a wall which is, say, 2 feet taller than you (so you cannot see over it); made out of sheet metal (so you cannot see through it); extremely thin (so you cannot jump & pull yourself up to peek over the top without slicing right through your hand); an integral part of the moulded structure of the lab so you cannot dismantle it without tools which are not available; you are naked (so you cannot use your clothes to make pads to protect your hand); there is no movable furniture in the room; every conceivable control is in place.
On the other side of the wall the coin is most definitely either heads or tails.
On your side of the wall it is still 50/50, both head & tail at the same time.
