Institutio Oratoria

Again oratory sometimes detects falsehoods closely resembling the truth by the use of geometrical methods. An example of this may be found in connexion with numbers in the so-called pseudographs, a favourite amusement in our boyhood. [*](It is not known to what Quintilian refers.) But there are more important points to be considered. Who is there who would not accept the following proposition?

When the lines bounding two figures are equal in length, the areas contained within those lines are equal.

But this is false, for everything depends on the shape of the figure formed by these lines,