be quite reasonable to connect
eating and death as cause and effect. The fact is that death is surer
to follow starvation. The glow at evening is generally followed by
fair weather the next day; but the fair weather is not an effect of a
clear sunset. Common sense must be used to determine whether the
relation is one of cause and effect; something more than a simple
sequence is necessary.

Another argument from sign associates conditions that frequently occur
together, though one is not the cause of the other. "James is near,
because there is his blind father," means that James always
accompanies his father; where the father is, the son is too. If one
had noticed that potatoes planted at the full of the moon grew well,
and potatoes planted at other times did not thrive, he might say as a
result of years of observation that a certain crop would be a failure
because it was not planted at the right time. This argument might have
weight with ignorant people, but intelligent persons do not consider
it a sure sign. All signs belong to this class of arguments; they are
of value or worthless as they come true more or less frequently. Every
time there is an exception the argument is weakened; another case of
its working strengthens it. Where there is no sure relation like cause
and effect, the strength of the argument depends on the frequency of
the recurrence of the associated conditions.

A third argument from sign associates two effects of the same cause. A
lad on waking exclaims, "The window is covered with frost; I can go
skating to-day." The frost on the window is not the cause of the ice
on the river. Rather, both phenomena are results of the same cause.
This kind of argument is not necessarily conclusive; yet with others
it always strengthens a case.

Testimony is usually called an argument from sign. The assertion by
some one that a thing occurred is not sure proof; it is only a sign
that it occurred. People have said that they have seen witches,
ghosts, and sea serpents, and unquestionably believed it; men
generally do not accept their testimony. In a criminal case, it would
be difficult to accept the testimony of both sides. Though testimony
seems a strong argument, it is or it is not, according to the
conditions under which it is given. One would care little for the
testimony of an ignorant man in a matter that called for wisdom; he
would hesitate to accept the testimony of a man who claimed he saw,
but upon cros