Change

Change in general may be defined as the variation of properties (whether of things or of regions of space) over time. But this definition is incomplete in a number of respects. The reference to properties and time raises two important questions. The first concerns whether we need to specify further the kinds of properties which are involved in change. If we define change in an object as temporal variation of its properties we are faced with the problem that some properties of an object may alter without there being a consequent change in the object itself. The second question concerns the passage of time: does temporal variation constitute change only in virtue of some feature of time itself, namely the fact (or putative fact) that time passes? Some philosophers have wished to reject the notion of time’s passage. Are they thereby committed to a picture of the world as unchanging?