At p. 19 of the 2nd Edition, the new Axiom, on which my Theory rests,
(which re-appears, in a modified form, at p. 14 of the 3rd Edition),
stood thus:—"In every Circle, the inscribed equilateral Hexagon
is greater than any one of the Segments which lie outside it." My
controversy with the Athenæum, on this Axiom, shall also be
given in the form of a dialogue.
Athenæum. (Oct. 27, 1888.) "... a stronger objection, in our
opinion, is the implied assumption of the possibility of the
inscribed equilateral Hexagon, a possibility which is not demonstrated
till we reach the fifteenth Proposition of Euclid's fourth book."
Author. (In the Preface to the 2nd Edition, at p. xi). "But does
it need demonstrating? May we not assume (1) that the
Magnitude 'four right angles' contains 6-6ths of itself; (2) that it
is theoretically possible to draw radii dividing it into these
6-6ths? Once grant me this, and I ask no more. I have then the logical
right to join the ends of these radii, and to prove (by Euc. I.
4) that the chords are equal."
[Pg xiii]
Athenæum. (Oct. 5, 1889.) "We objected that it was not
consistent with the spirit or practice of Euclid's reasoning to assume
the 'theoretical possibility' of a regular Hexagon inscribed in a
Circle, without first proving that such a figure could be actually
constructed from his three postulates. Euclid's restrictions may be
arbitrary, unnecessary, cramping, vexatious, absurd—indeed, we think
they deserve these and many other epithets—but there they are, and, if
Mr. Dodgson accepts them, he is bound to keep his assumptions within
the boundaries which they prescribe."
Author. "You're particular to a shade (as Scrooge said to
Marley's ghost): however, I'll do what I can to oblige you. I presume
you will be satisfied if I can, without using more of Euclid than his
first 28 Propositions, construct an angle which shall be 1-6th of 4
right angles? Very good. First, then, with the help of his arbitrary
Prop. I, I construct an equilateral Triangle. Next, by his unnecessary
Prop. IX, I draw the bisectors of 2 of its angles. Next, by his
cramping Post. 1, I join their point of intersection to the third
vertex. Next, by his vexatious Prop. IV, I prove the 3 angles, whose
common vertex is this point, to be equal. From which I draw the absurd
conclusion that each of them is 1-3rd (and that therefore its half is
1-6th) of 4 right angles. How does that strike you?"
Public-domain text, read in full here on John Shaqi.
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