We are ready for any unforeseen event that may or may not occur. Dan Quayle
A man will be imprisoned in a room with a door that's unlocked and opens inwards; as long as it does not occur to him to pull rather than push. Ludwig Wittgenstein
Quantum phenomena do not occur in a Hilbert space. They occur in a laboratory. Asher Peres
Music, states of happiness, mythology, faces belabored by time, certain twilights and certain places try to tell us something, or have said something we should not have missed, or are about to say something; this imminence of a revelation which does not occur is, perhaps, the aesthetic phenomenon. Jorge Luis Borges
The future is inevitable and precise, but it may not occur. God lurks in the gaps. Jorge Luis Borges
The economic concept of value does not occur in antiquity. Karl Marx