The one-day announcement is a blindspot.But the first premise is indisputable and I have also explained why I think the second must be granted. In my opinion, there is nothing for it but to conclude that this is just an instance of the paradox of the heap!If the n-day announcement is a blindspot, then so is the (n+1)-day announcement.
it follows that any number of grains is not a heap of sand, i.e., there is no such thing as a heap of sand. Naturally, this is absurd, but the first claim is obviously true, while the second, though occasionally contested, is equally hard to dispute. (How can one grain of sand separate a non-heap from a heap?)One grain of sand is not a heap of sand.If n grains of sand is not a heap of sand, then neither is n+1 grains.