“For in them the variation of great parcels of matter alters not the identity: An oak growing from a plant to a great tree, and then lopped, is still the same oak; and a colt grown up to a horse, sometimes fat, sometimes lean, is all the while the same horse: Though in both these cases, there may be a manifest change of the parts; so that truly they are not either of them the same masses of matter, though they be truly one of them the same oak, and the other the same horse. The reason whereof is, that in these two cases, a mass of matter, and a living body, identity is not applied to the same thing” (Chapter 27, paragraph 3).
Many authors, especially philosophers, turn to beautiful metaphors to describe their ideas to readers. Here, Locke follows this ancient tradition, furthering his claim that variation does not alter identity through the example of the development of an oak tree and maturation of a horse.
I found these metaphors to be not only eloquent and engaging but also great illustrations of his assertion. In order to further his point that “variation” in “matter alters not the identity,” he describes an oak starting out as a small shoot and then growing into a “great tree,” showing that just because the shape of the tree changes, its element is not transformed: it is still composed of wood and undergoes the process of photosynthesis in order to survive.
Furthermore, he writes of how when a colt matures to a horse, growing either “fat” or “lean,” it is still “the same horse” by nature. Its physical attributes does not change the fact that larger horses and skinnier horses are still the same horse, just with different characteristics, such as either an enlarged or shrunken frame. The horses’ “matter,” or what makes the horses horses never changes.
As “parts” change, the object changes into a different form of that same object; however, its identity does not change in relation to these so-called “great parcels of matter.” According to Locke, its identity remains the same. Here, he writes that, in the sake of using the tree metaphor, as long as the tree has the ability to do its same biological functions through appendages that make it a tree, such as roots, trunk, and branches, in the furthering of its life as an organism, the tree continues to exist as one and the same tree, despite the changes in its constituent matter. He, therefore, concludes that even though living organisms constantly lose and gain portions of their matter through process of growth and aging, we are not inclined to believe that they have changed into different creatures. The identity of organisms is based on their ability to sustain the biological processes that keep them alive. In conclusion, Locke believes that identity is founded upon this principle, and that the only time such identity shifts is when something separates from the original organism and gains a life of its own.