Cambridge change
A Cambridge change is a philosophical concept of change according to which an entity x has changed if, and only if there is some predicate F that is true (not true) of x at a time t1 but not true (true) of x at some later time t2.
History
The term Cambridge change was coined by Peter Geach in the late 1960s,[1][2] in reference to Russell and McTaggart, philosophers active at Cambridge University.
Example
Suppose that at t1, person A is 180 cm tall and person B is 175 cm tall, while at time t2 A is still 180 cm tall but B has grown to be 185 cm tall. Since the predicate `is taller than B' is true of A at t1 but not true of A at t2, A has changed according to the Cambridge change definition of "change"---he has gone from being taller than B to not being taller than B.
Intuitively, however, it is only person B, and not person A, who has changed: B has grown by 10 cm, but A has stayed the same. This problem with Cambridge changes is usually thought to call for a distinction between intrinsic and extrinsic, or natural and non-natural, properties. Given such a distinction, it is possible to define "real" change by requiring that the predicate involved express an intrinsic property, like being 175 cm tall, rather than an extrinsic property, like being taller than B.