Actions And Activity is a key paper by Hornsby. I will make some comments on it here. What is an action?
Is the raising of someone’s arm one event or two? Is the event `I raised my arm’ identical to the event `my arm rose’? Resolving this question should throw light on what an action is. We also need to know whether an event which goes on for a period is going on during all instants of that period, for the same reason.
There is a distinction between `A stroll was going on at t’ and `strolling was going on at t’. The former at least seems to require an agent – but Hornsby’s point is that the latter does not seem to rely on any particular event (a ‘stroll’) taking place. Strolling is an activity – it must have a duration, as must `raising one’s arm’.
Actions and Activity and Stuff
Actions and activity are like stuffs. Saying `there is beer in the fridge’ does not refer to any particular can of beer or any particular beer atoms. There just has to be some in there, if the claim is to be true. Likewise, a stroll can be taking place without any particular event of strolling being necessary – distinguish this carefully from the very similar appearing but completely different claim that a stroll can be taking place without any event of strolling being necessary.
Q: Hornsby also seems to want to remain open to the possibility of the latter claim. Does she need this? Is it plausible?
This brings in the agent. There can be no strolling by Sebastian unless there is an action of strolling being done by Sebastian. Note again that there need be no event of strolling by Sebastian going on, on Hornsby’s line.
Beer Pervasion: Actions and Activity
Hornsby claims that “just as beer pervades any volume of space occupied by beer, so strolling pervades any interval of time occupied by strolling.” Actions and activity are pervasive in a technical sense.
Q: these claims do indeed appear to stand or fall together, but both are highly questionable from a physics/chemistry perspective. There are no beer atoms, but even if there were, what would we say about the space between the atoms? – should such a space be a coherent idea. Similarly, time quantisation at micro-intervals may make it difficult to talk about anything pervading them. Does anyone stroll during an interval in which light would travel a billionth of the diameter of a proton? Does that make any sense?
Accomplishments and Achievements
There is a useful distinction between accomplishments and achievements, due to Mourelatos.
The latter are punctate: Mary’s finding the book ceases when she finds it. It would not become the case that she was finding the book until she finds it, when there is something a little like backwards causation – it becomes the case now that what she was doing then was finding the book – if she finds it. Accomplishments do not have this character: strolling can have its character as strolling from the point it begins and it continues until it ceases. Achievements are not composed of activity but accomplishments are. It does not take any time for John to win the sprint.
Q: really? Not even a 100 billionth of a second?