[tsimionescu]

Bit late, but I probably should have given virtual particles as a better example. Those are theorized to appear and disappear at random out of the void. Per the theory, there is no cause to this appearance (apart from it being permitted by the laws of physics).

Of course, this is ultimately a model and can be wrong. But my point is that we can definitely conceive of models of the world in which causality is not a strict requirement - and not just fantasy ones, but very concrete models with workable predictions.