ence, even where appeal can be made to actual eyesight. Eyesight,
in fact, is the least part of the matter. The senses are as often the
tools as the guides of reason. One of the longest chapters in the
history of vulgar error would contain the cases in which the eyes have
only seen what old prepossessions inspired them to see, and were blind
to all that would have been fatal to the prepossessions. 'It is beyond
all question or dispute,' says Voltaire, 'that magic words and
ceremonies are quite capable of most effectually destroying a whole
flock of sheep, if the words be accompanied by a sufficient quantity
of arsenic.' Sorcery has no doubt been exploded--at least we assume
that it has--but the temper that made men attribute all the efficacy
to the magic words, and entirely overlook the arsenic, still prevails
in a great host of moral and political affairs, into which it is not
convenient to enter here. The stability of a government, for instance,
is constantly set down to some ornamental part of it, when in fact the
ornamental part has no more to do with stability than the incantations
of the soothsayer.

You have heard, again, that for many generations the people of the
Isle of St. Kilda believed that the arrival of a ship in the harbour
inflicted on the islanders epidemic colds in the head, and many
ingenious reasons were from time to time devised by clever men why the
ship should cause colds among the population. At last it occurred to
somebody that the ship might not be the cause of the colds, but that
both might be the common effects of some other cause, and it was then
remembered that a ship could only enter the harbour when there was a
strong north-east wind blowing.

However faithful the observation, as soon as ever a man uses words he
may begin at that moment to go wrong. 'A village apothecary,' it has
been said, 'and if possible in a still greater degree, an experienced
nurse, is seldom able to describe the plainest case without employing
a phraseology of which every word is a theory; the simplest narrative
of the most illiterate observer involves more or less of
hypothesis;'--yet both by the observer himself and by most of those
who listen to him, each of these conjectural assumptions is treated as
respectfully as if it were an established axiom. We are supposed to
deny the possibility of a circumstance, when in truth we only deny the
evidence alleged for it. We allow the excellence of reasoning from
certa