The English works of Thomas Hobbes of Malmesbury, Volume 07 (of 11)
Thomas Hobbes · en
The row above is 36, the fourth part of the row below is 27. The
quadruple of the number of terms after 0 is 12. Then, by your account,
the proportion of 36 to 108 is greater than subquadruple proportion by
the proportion of 1 to 12. For trial whereof, set in order these three
quantities, 36, 27, 108. The proportion of 36 (the uppermost row) to 108
(the lowermost row) is compounded by addition of the proportions 36 to
27, and 27 to 108. And the proportion of 36 to 108, exceedeth the
proportion of 27 to 108, by the proportion of 36 to 27. But the
proportion of 27 to 108 is subquadruple proportion. Therefore, the
proportion of 36 to 108 exceedeth subquadruple proportion, by the
proportion of 36 to 27. And, by your account, by the proportion of 1 to
12; and, consequently, as 36 to 27, so is 1 to 12. Did you think such
demonstrations as these should always pass?
Then, for your inference from the decrease of the proportions of the
excess, to the vanishing of the excess itself, I have already showed it
to be false; and by consequence that your next proposition, namely, the
fortieth, is also false.
The proposition is this:
“_Si proponatur series infinita quantitatum in triplicata ratione
arithmetice proportionalium (sive juxta seriem numerorum cubicorum),
continue crescentium a puncto sive 0 inchoatarum, erit illa ad seriem
totidem maximæ æqualium, ut 1 ad 4, patet ex præcedente._”
That is, if there be propounded an infinite row of quantities in
triplicate proportion of arithmetically proportionals (or according to
the row of cubic numbers), continually increasing, and beginning at a
point or 0; it shall be to the row of as many equals to the greatest as
1 to 4. Manifest out of the precedent proposition.
Even as manifest as that 36, 27, 1, 12, are proportionals. Seeing,
therefore, your doctrine of the spiral lines and the spaces is given by
yourself for lost, and a vain attempt, your first forty-one propositions
are undemonstrated, and the grounds of your demonstrations all false.
The cause whereof is partly your taking quotient for proportion, and a
point for 0, as you do in the first, sixteenth, and fortieth
propositions, and in other places where you say, _beginning at a point
or 0_, though now you deny you ever said either. There be very many
places in your _Elenchus_, where you say both; and have no excuse for
it, but that, in one of the places, you say the proportion is _penes
quotientem_, which is to the same or no sense.
Your forty-second proposition is grounded on the fortieth; and
therefore, though true, and demonstrated by others, is not demonstrated
by you.
Your forty-third is this: