The English works of Thomas Hobbes of Malmesbury, Volume 07 (of 11) — Thomas Hobbes — John Shaqi
The English works of Thomas Hobbes of Malmesbury, Volume 07 (of 11)
Thomas Hobbes · en
The eighth is of a plane angle, Ἑπὶπεδος γωνία ἑϛὶν ἡ ἐν ἐπιπέδω, &c.
“_Angulus planus est duarum linearum in plano se mutuo tangentium, et
non in directum jacentium, alterius ad alteram inclinatio._” _A plane
angle is the inclination one towards another of two lines that touch one
another in the same plane, and lie not in the same straight line._
Besides the faults here observed by Sir Henry Savile, as the clause of
not lying in the same straight line, and the obscurity or equivocation
of the word _inclination_, there is yet another, which is, that by this
definition two right angles together taken, are no angle; which is a
fault which you somewhere (asking leave to use the word _angle_,
καταχριϛικώς acknowledge, but avoid not. For in geometry, where you
confess there is required all possible accurateness, every καταχρῆσις is
a fault. Besides you see by this definition, that Euclid is not of your,
but of Clavius’s opinion. For it is manifest that the two lines which
contain an angle of contact incline one towards another, and come
together in a point, and lie not in the same straight line, and
consequently make an angle.
The thirteenth definition is exact, but makes against your doctrine,
that a point is nothing. Examine it. Ὅρος ἐϛὴν ὅ τινός ἐϛῖ πέρας.
“_Terminus est quod alicujus extremum est._” _A term or bound is that
which is the extreme of anything._ We had before, _the extremes of a
line are points_. But what is in a line the extreme, but the first or
last _part_, though you may make that part as small as you will? A point
is therefore a part, and nothing is no extreme.
The fourteenth, Σχῆμα ἐϛὶ τὸ ὑπὸ τινος ἤ τινῶν ὅρων περιεχόμενον.
“_Figura est (subaudi quantitas) quæ ab aliquo, vel aliquibus terminis
undique continetur sive clauditur._” _A figure is quantity contained
within some bound or bounds._ Or shortly thus, _a figure is quantity
every way determined_, is in my opinion as exact a definition of a
figure as can possibly be given, though it must not be so in yours. For
this _determination_ is the same thing with _circumscription_; and
whatsoever is anywhere _(ubicunque) definitivè_ is there also
_circumscriptivè_; and by this means the distinction is lost, by which
theologers, when they deny God to be in any place, save themselves from
being accused of saying he is nowhere; for that which is nowhere is
nothing. This definition of Euclid cannot therefore possibly be embraced
by you that carry double, namely, mathematics and theology. For if you
reject it, you will be cast out of all mathematic schools; and if you
maintain it, from the society of all school-divines, and lose the thanks
of the favour you have shown (you the astronomer) to Bishop Bramhall.