The property of well-behaved objects in space and time, that they do not ‘jump’, or in other words if a body exists at one time and a later time, then it exists throughout the interval, and if it is in one place at a time and a different place at a later time, then it traced a path through space from the one place to another. This behaviour may not belong to objects in the quantum world, and there are questions of whether it is essential or only accidental for ordinary bodies, and especially for persons, where science fiction scenarios often transgress it.