Item talk:Q161222

Amounts of matter refer to volumes of substances such as some gold, wood, iron, water, air, etc. As per Lowe (1998), an amount of matter is either a chunk (unified "part") or heap (separated and not unified "piece"). A unified chunk of matter is an integral whole (with a unifying condition), is mereologically invariant (can gain or lose parts without loss of identity), is discretely countable (the number of gold ore bodies or sandstone layers can be enumerated), has a single self-connected boundary upon which it is mutually ontologically dependent (the chunk cannot exist essentially without the boundary, and the boundary cannot exist essentially without the chunk), and is a single entity (self-connected, unfragmented). Being an integral whole, a chunk of matter must then have some amount of matter as an essential part (Brodaric et al. 2019). In contrast, a nonunified heap is mereologically variant, uncountable, and not dependent on a boundary, e.g. a heap of gold grains in an ore body or sand particles on a beach. Moreover, each unified chunk of matter is constituted by an ununified heap of matter, as well as possibly by particles of lower granularity, and can constitute larger amounts of matter or objects: e.g. an amount of mineral is a disaggregated heap of individual unit mineral cells made up by a certain configuration of atoms, and this heap of minerals makes up a single chunk of mineral locked together under binding conditions; the chunk in turn makes up a rock material, which makes up a formation. Note that both chunks and heaps can thus constitute objects: a gold ring is constituted by the chunk and its heap of gold, and a formation is constituted by both the sandstone and its heap of sand and other particles. Even things that seem to be intrinsically heaps, such as a dune, are constituted by both heaps and chunks of matter: e.g. by both a heap of sand particles and a chunk of sand (with a discrete shape and boundary). The chunk (of sand) differs from the object (the dune), in the sense that the dune has additional essential characteristics not held by the chunk, such as being a landform (i.e. located on the land surface), having a specific shape (hilly - even though the chunk has the shape, the shape is not essential to it, but is essential to the dune), and is formed by certain geomorphological processes such as wind or water flow (the sand chunk is formed by erosion and weathering). Distinguishing chunks from heaps is important to geology, as it enables chunks to have characteristics of unified matter, which otherwise would be restricted to objects, e.g. one could not then say, for example, some sandstone hosts a fault, but rather that the rock object part constituted by the sandstone hosts the fault. This then enables detailed representation of micro-scale geology, at the granularity of matter, in addition to representation of macro-scale entities such as units or basins.