When Socrates Says, "Do You See, Meno, What Advances He

When Socrates says, "Do you see, Meno, what advances he [the boy] has made in his power of recollection? He did not know at first, and he does not know now, what is the side of a figure of eight feet. But then he thought that he knew, and answered confidently as if he knew, and had no difficulty. Now he has a difficulty, and neither knows nor thinks that he knows," Socrates' point is that the boy doesn't understand basic Geometry.