Philosophical Works, v. 1 (of 4): Including All the Essays, and Exhibiting the More Important Alterations and Corrections in the Successive Editions Published by the Author — David Hume — John Shaqi
Philosophical Works, v. 1 (of 4): Including All the Essays, and Exhibiting the More Important Alterations and Corrections in the Successive Editions Published by the Author
David Hume · en
standard of a right line is in reality nothing but a certain general
appearance; and 'tis evident right lines may be made to concur with
each other, and yet correspond to this standard, though corrected by
all the means either practicable or imaginable.
To whatever side mathematicians turn, this dilemma still meets them.
If they judge of equality, or any other proportion, by the accurate
and exact standard, viz. the enumeration of the minute indivisible
parts, they both employ a standard, which is useless in practice,
and actually establish the indivisibility of extension, which they
endeavour to explode. Or if they employ, as is usual, the inaccurate
standard, derived from a comparison of objects, upon their general
appearance, corrected by measuring and juxtaposition; their first
principles, though certain and infallible, are too coarse to afford
any such subtile inferences as they commonly draw from them. The first
principles are founded on the imagination and senses; the conclusion
therefore can never go beyond, much less contradict, these faculties.
This may open our eyes a little, and let us see, that no geometrical
demonstration for the infinite divisibility of extension can have so
much force as what we naturally attribute to every argument, which
is supported by such magnificent pretensions. At the same time we
may learn the reason, why geometry fails of evidence in this single
point, while all its other reasonings command our fullest assent and
approbation. And indeed it seems more requisite to give the reason
of this exception, than to show that we really must make such an
exception, and regard all the mathematical arguments for infinite
divisibility as utterly sophistical. For 'tis evident, that as no idea
of quantity is infinitely divisible, there cannot be imagined a more
glaring absurdity, than to endeavour to prove, that quantity itself
admits of such a division; and to prove this by means of ideas, which
are directly opposite in that particular. And as this absurdity is
very glaring in itself, so there is no argument founded on it, which
is not attended with a new absurdity, and involves not an evident
contradiction.