In first-party property cases involving multiple perils, courts use the
"but for" test to determine whether a given peril is a cause-in-fact
of the loss. To do that, courts conduct a "thought experiment" and
imagine what would happen if one of the perils did not occur. If the loss would
have happened anyway with or without the occurrence of the removed peril, then
the removed peril fails the "but for" test. What that means is that
the removed peril is not really a cause-in-fact of the loss, so it cannot be
selected as the proximate cause.