Socrates begins one
of the most influential dialogues of Western philosophy regarding the
argument for inborn knowledge. By drawing geometric figures in the ground Socratesdemonstrates that the slave is initially unaware of the length of side thatmust be used in order to double the area of a square with two-foot sides. Theslave guesses first that the original side must be doubled in length (fourfeet), and when this proves too much, that it must be three feet. This is stilltoo much, and the slave is at a loss.
Socrates claims that
before he got hold of him the slave (who has been picked at random from Meno's
entourage) might have thought he could speak "well and fluently" on
the subject of a square double the size of a given square. Socrates comments that this "numbing" he caused in the slave
has done him no harm and has even benefited him
Socrates then draws a second square figure using the diagonalof the original square. Each diagonal cuts each two foot square in half,yielding an area of two square feet. The square composed of four of the eightinterior triangular areas is eight square feet, double that of the originalarea. He gets the slave to agree that this is twice the size of the originalsquare and says that he has "spontaneously recovered" knowledge heknew from a past life[14] without having been taught. Socrates is satisfied that newbeliefs were "newly aroused" in the slave.