If a man stands before a mirror and sees in it his reflection, what he sees is not a true reproduction of himself but a picture of himself when he was a younger man. De Selby's explanation of this phenomenon is quite simple. Light, as he points out truly enough, has an ascertained and finite rate of travel. Hence before the reflection of any object in a mirror can be said to be accomplished, it is necessary that rays of light should first strike the object and subsequently impinge on the glass, to be thrown back again to the object to the eyes of a man, for instance. There is therefore an appreciable and calculable interval of time between the throwing by a man of a glance at his own face in a mirror and the registration of the of the reflected image in his eye
What a strange argument, I always feel the opposite: I look older than I think I am. Someone says you should never look at yourself in the elevator mirror, not even when you are 20 years old, and I guess he is right
As for O´Brien´s text, it´s an excessive version of the famous twin paradox of Einstein, in which a second brother is not even necessary. As they say, an exaggeration is sometimes the most accurate lie
