s to assume, that these secondary causes,
under certain conditions, which we never have seen, and never can see,
realized, might produce very extraordinary results, might even fully
account for the wonderful effects in question, we have a right to say,
in reply, that he is dealing in pure speculation and hypothesis; that,
having had no experience under the conditions or postulates of his
theory, he is necessarily _speaking from_ ignorance and _appealing_ to
ignorance; that, even if we could not point out a single difficulty, a
single false assumption, in his whole scheme and argument, it would
still remain a mere hypothesis, alike incapable of proof or disproof;
and that, at the best, the arguments brought against it must be of
nearly the same wiredrawn, speculative, and far-fetched character with
those adduced in its support. On a mere sandbank, unsupplied either with
arms or tools, the only edifice that can be built is one of sand, and
sand affords the only means for its destruction. The fallacy to which
such speculatists constantly have resort is, that the weakness or the
entire absence of all considerations against their theory constitutes a
positive argument in its support. No such thing; it affords only a fair
presumption of the baseless character of the whole fabric.

This may be made more clear by examples. If a child, who has had little
experience of the laws of nature, and has learned nothing from books, is
gravely assured by his instructor, that in a distant region of the ocean
there is an island where stones fly upward instead of downward, and men
walk on their heads instead of their feet, the young philosopher,
however acute and ingenious we may suppose him to be, certainly could
not offer one valid argument against the alleged fact. He could only
stare, and wonder, and say that it might be so _for all that he knew to
the contrary_. Just so, when the atheist tells us, that far off in
infinite space is a region, of which we can see nothing, even with our
best telescopes, except a faint glimmer of light, floating like a
cloudlet in the heavens, where the primitive atoms of matter, directed
by gravity alone, are slowly congregating together, and forming suns,
and planets, and secondary satellites, and giving birth to such
intricate harmonies of mutually dependent and revolving worlds as those
which have prevailed for ages in our own system; or that, thousands of
years ago, the same unassisted laws of matter, wh