Because I've been reading some books on alternative history, commonly called counterfactual history, I followed up this post on Crooked Timber to dicover it is in reality about a mind-numbing philosphical point. I persevered nevertheless, starting to read this paper (called Causation and Preemption), and before my head started aching too much I got to the diagram below (Fig 5 on p12).
The shaded circles represent events while the lines represent the path of the triggering action. A line with an arrow represents a positive effect, whcile a line with a circle represnts an inhibitory effect.
Assume A fires with strength 10 which in turn triggers B and then E. E requires an input of 10 to fire. Assume also C fires with strength 10, 5 going to D as trigger and 5 going to B as inhibitor. As a consequence of the presence of C, B therefore fires only with a net strength of 5.
However the combined effect of D and B is still 10, enough to trigger E which fires. Clear so far?
This looks at first blush to be one of those pretty but essentially irrelevant (to the day to day world at least) philosophical problems. In practice though I'm not sure.
Consider the arrows as flows of information in the real world.
In the absence of the flow C>D>E, E still happens - as a consequence of the flow A>B>E. The 'composition of E however is different in the two cases.
If C then E is effectively 50% D>E and 50% B>E. If not C then E is 100% B>E.
Is E therefore the same event in both circumstances?
I appreciate this very issue may be covered in the paper, but if it is I couldn't find it - or perhaps understand it!
