Elements of the philosophy of the human mind. By Dugald Stewart. Rev. and abridged, with critical and explanatory notes, for the use of colleges and schools. By Francis Bowen ...

REASONING AND DEDUCTIVE EVIDENCE. 485
th..e the experiments and observations which we make with
respect to one individual, may be safely extended to the whole
class. It is experience alone that teaches us caution in such
inferences, and subjects the natural principle to the discipline
prescribed by the rules of induction.
How this disposition is corrected. - It must not, however, be
imagined, that, in instances of this sort, the instinctive principle
always leads us astray; for the analogical anticipations which
it disposes us to form, although they may not stand the test of
a rigorous examination, may yet be sufficiently just for all the
common purposes of life. It is natural, for example, that a
man who has been educated in Europe should expect, when he
changes his residence to any of the other quarters of the globe,
to see heavy bodies fall downwards, and smoke to ascend, agreeably to the general laws to which he has been accustomed; and
that he should take for granted, in providing the means of his
subsistence, that the animals and vegetables which he has found
to be salutary and nutritious in his native regions, possess the
same qualities wherever they exhibit the same appearances.
Nor are such expectations less useful than natural; for they are
completely realized, as far as they minister to the gratification
of our more urgent wants. It is only when we begin to indulge
our curiosity with respect to those nicer details, which derive
their interest from great refinement in the arts, or from a very
advanced state of physical knowledge, that we discover our first
conclusions, however just in the main, not to be mathematically
exact; and are led by those habits which scientific pursuits
communicate, to investigate the difference of circumstances
to which the variety in the result is owing. After having
found that heavy bodies fall downwards at the equator
as they do in this island, the most obvious, and perhaps, on
a superficial view of the question, the most reasonable, inference would be, that the same pendulum which swings seconds
at London, will vibrate at the same rate under the line. In
this instance, however, the theoretical inference is contradicted
by the fact; — but the contradiction is attended with no
practical inconvenience to the multitude, while, in the mind
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