The creators of equilibrium and irreversible thermodynamics developed a conception of processes which bears on metaphysical discussions of change, occurrents, and continuants and merits the attention of contemporary analytic metaphysicians. It concerns the macroscopic domain, from which metaphysicians normally take their examples, and is unjustly ignored on the grounds that it is not ‘fundamental science’. Why this often-voiced view should disqualify just thermodynamics, and not the broad range of considerations normally raised, is a moot point. But even if there were (...) an adequate reductive argument, that wouldn’t eliminate the ontological claims. It is argued that processes cannot be defined as changes in the state of enduring objects, but should be considered autonomous entities. The relational character of processes involving several continuants is developed, alongside their mereological features and their relation to space and time. Some aspects of the historical development of the notions of reversible and irreversible processes in thermodynamics are taken up in the course of the discussion, but the paper is not concerned with the mathematical foundations of equilibrium and irreversible thermodynamics. 1 Introduction2 Change3 Distinguishing Processes from States4 Causings5 The Relational Character and Mereological Structure of Processes6 Concluding Comments. (shrink)

Traditionally, this puzzle has been solved in various ways. Aristotle, for example, distinguished between “accidental” and “essential” changes. Accidental changes are ones that don't result in a change in an objects' identity after the change, such as when a house is painted, or one's hair turns gray, etc. Aristotle thought of these as changes in the accidental properties of a thing. Essential changes, by contrast, are those which don't preserve the identity of the object when it changes, such as when (...) a house burns to the ground and becomes ashes, or when someone dies. Armed with these distinctions, Aristotle would then say that, in the case of accidental changes, (1) and (2) are both false—a changing thing can really change one of its “accidental properties” and yet literally remain one and the same thing before and after the change. (shrink)

Material objects extend through space by having different spatial parts in different places. But how do they persist through time? According to some philosophers, things have temporal parts as well as spatial parts: accepting this is supposed to help us solve a whole bunch of metaphysical problems, and keep our philosophy in line with modern physics. Other philosophers disagree, arguing that neither metaphysics nor physics give us good reason to believe in temporal parts.