Parts and Wholes
Parthood has puzzled metaphysicians for a long time. How are parts of things related to whole things?
Take an object, say, a table. It has parts: wood, atoms, subatomic particles … Why is it the case that there is a whole thing called a table as well? The mereological nihilist claims that there are only fundamental parts (‘simples’ or ‘atoms’) merely arranged ‘table-wise’.
Yet philosophers of classic mereology offer some arguments we may want to consider before we subscribe to such a view. For example, there is composition, a mereological fusion of many parts (e.g. a cocktail); group membership (e.g. sports team); and constitution, a one-one relation between co-located objects, which takes us to an interesting example …
The statue and the clay
Take JJ Thomson’s example of a statue made from clay. The statue is one object; the clay from which it is built is another. The problem is that two objects seem to occupy the same space at the same time, upsetting the monist :’(
However, according to pluralism, it can be okay to accept this situation because the two have different identities.
But how? Well, we could use the concept of time to say that whereas the lump of clay appeared at t1, the statue came into existence at t2. We could also reference additional features the statue has (like ears), its aesthetic value (beauty), or some defining property.
Reversing intuition
Parthood follows intuition. In language we often tacitly suggest that there are ‘proper’ parts to things (e.g. ‘grains of sand’ and ‘organs’) which make up wholes (e.g. ‘a heap of sand’ and ‘an organism’), not the other way round.
But why let our dodgy common sense rule how we think the world is? We might instead talk of wholes first—wholes which possess emergent properties that parts as mere aggregates do not.
Alternatively, we might believe in ‘gunk’: that all constituents of the Universe are infinitely divisible: that parts have their own parts, which have their own parts, and so on.
But then in what sense is a thing—such as a table—really a thing? Is there anything? If there is, where is the line? Does identity depend on the spatial proximity of its parts? Unscrewing a table leg ever so slightly, does the table’s identity change? Why more so than throwing the leg over the fence and onto my neighbour’s garden? The argument for proximity feels weak.
A final thought
As a metaphysical relation, parthood putatively comes as many modes. There is a part-whole structure to a statue and clay, to a set of prime numbers, to an espresso martini, to a fact and its constituents, to spacetime and its regions, to an immaterial soul … Why? How?
Reality is weird.