An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

OR SCIENTIFIC METHOD. 307
must not contradict itself. If, on the other hand,
"conceivable" means "easy to imagine" in the sense
of picturing the meaning to one s mind, then it is not
true to say that a legitimate hypothesis must be "con
ceivable." It is not easy to imagine the antipodes,
where
"
to go
"
up means to go in a direction diamet
rically opposite to that which we so describe ; it is not
easy to imagine that \ve are moving through space with
great velocity in two different directions at once. It is
not easy to imagine that if an organ were played by
machinery in a hall, and there were no living creatures
in or near it, it would make no sound. It is harder still
to imagine that we live and move in a perfectly solid
and elastic medium, possessing no weight, and capable
of nine hundred millions of millions of vibrations in a
second of time. For similar reasons it is a mistake to
make the rule say that a legitimate hypothesis must not
conflict with any of the "received" or "accepted" laws
of Nature. The rule means that, though an hypothesis
may be new or strange i.e., may conflict with the
apparent implications of previous knowledge it may
still be legitimate. And it is legitimate if, when we
consider both what the hypothesis implies and what
is implied in our previously accepted knowledge, the
discrepancy can be shown to be only apparent. This
may require a modification of the received knowledge,
by which it is set in a new light ; and it may require a
modification of the hypothesis also. Thus, the sup
position of the "antipodes" was once believed to be in
conflict with ordinary experience, for it seemed to mean
that on the other side of the earth were people living
with their heads "downwards." The difficulty was
removed when it was understood that
"
"
down
means
only the direction in which the mass of the earth attracts