Databases Reference
In-Depth Information
•
Connection dependence:
If the connection between cause and effect were
broken, only the effect would be affected
β
) have a place; although they
may result in less certainty in reasoning. For example:
Counterfactuals or negation (
¬
α
→¬
If a person drinks
wine
, they may become inebriated.
cannot be simply negated to
If a person
does not
drink
wine
, they will
not
become inebriated.
One reason is that effects can be
overdetermined
; that is: more than one item
can cause an effect. Eliminating one cause does not necessarily eliminate the
effect. In this case:
A person may also drink
beer
or
whiskey
to excess and become inebri-
ated.
Events that do
not
happen can similarly be overdetermined. From a common-
sense reasoning view, it is more likely that things do not happen than they
do. For example, [19] states that it is not true that
His closing the barn door caused the horse not to escape.
because the horse might not have attempted to escape even if the door was
open. Therefore, a false counterfactual is:
If he had not closed the barn door, the horse would have escaped.
Similarly, for example, the rule
If a person smokes, they will get cancer.
cannot be simply negated to
If a person
does not
smoke, they will
not
get cancer.
Again, effects can be overdetermined. In this case,
People who do not smoke may also get cancer.
So far, this discussion has been on possible overdetermination; that is, the
potential causes do not co-occur (the occur independently of each other). The
other case is when potential causes happen at the same time. For example,
when two rocks shatter a window at the same time, what causes the win-
dow to shatter [23]? Is the throwing of each individual rock a cause of the
window shattering, or is it a collective cause (all the “throwings” combined).
Lewis [12] calls this
redundant causation
; that is, whenever there are multiple
actual distinct events,
c
1
,c
2
,...c
n
,
event such that each
c
j
without the other
c
s
would cause an
event
.
Preemption
(asymmetric redundancy) occurs whenever
