e that it is so, is
the familiar fallacy of arguing '_post hoc ergo propter hoc_.' Every
event has an infinite number of antecedents that have no ascertainable
connection with it: if a picture falls from the wall in this room, there
may have occurred, just previously, an earthquake in New Zealand, an
explosion in a Japanese arsenal, a religious riot in India, a political
assassination in Russia and a vote of censure in the House of Commons,
besides millions of other less noticeable events, between none of which
and the falling of the picture can any direct causation be detected;
though, no doubt, they are all necessary occurrences in the general
world-process, and remotely connected. The cause, however, was that a
door slammed violently in the room above and shook the wall, and that
the picture was heavy and the cord old and rotten. Even if two events
invariably occur one after the other, as day follows night, or as the
report follows the flash of a gun, they may not be cause and effect,
though it is highly probable that they are closely connected by
causation; and in each of these two examples the events are co-effects
of a common cause, and may be regarded as elements of its total effect.
Still, whilst it is not true that every antecedent, or that every
invariable antecedent, of an event is its cause, the cause is conceived
of as some change in certain conditions, or some state and process of
things, such that should it exactly recur the same event would
invariably follow. If we consider the antecedent state and process of
things very widely or very minutely, it never does exactly recur; nor
does the consequent. But the purpose of induction is to get as near the
truth as possible within the limits set by our faculties of observation
and calculation. Complex causal instances that are most unlikely to
recur as a whole, may be analysed into the laws of their constituent
conditions.

(5) The Cause is the Unconditional Antecedent. A cause is never simple,
but may be analysed into several conditions; and 'Condition' means any
necessary factor of a Cause: any thing or agent that exerts, absorbs,
transforms, or deflects energy; or any relation of time or space in
which agents stand to one another. A positive condition is one that
cannot be omitted without frustrating the effect; a negative condition
is one that cannot be introduced without frustrating the effect. In the
falling of the picture, e.g., the positive conditions we