Changing objects (of any nature) pose a difficulty for the metaphysically-minded logician known as the Paradox of Change. Suppose a green apple becomes red. If A denotes the apple when green, and B when it is red then A = B (it is the same thing) but the properties of A and B are different: they have a different color. This is at odds with the Indiscernibility of Identicals thesis according to which identical things have identical properties.